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Sample records for viologen paraquat bishexafluorophosphate

  1. Complexation between Methyl Viologen (Paraquat) Bis(Hexafluorophosphate) and Dibenzo[24]Crown-8 Revisited

    DEFF Research Database (Denmark)

    Gasa, Travis B.; Spruell, Jason M.; Dichtel, William R.

    2009-01-01

    Paraquat bis(hexafluorophosphate) undergoes stepwise dissociation in acetone. All three species - the neutral molecule, and the mono- and dications - are represented significantly under the experimental conditions typically used in host-guest binding studies. Paraquat forms at least four host...... toward dibenzo[24]crown-8. Thus, the relative abundance of neutral, singly, and doubly charged pseudorotaxanes is identical to the relative abundance of neutral, singly, and doubly charged paraquat unbound with respect to the crown ether in acetone. In the specific case of paraquat/dibenzo[24]crown-8...

  2. Paraquat-induced radiosensitization of mammalian cells

    International Nuclear Information System (INIS)

    Miller, R.C.; Fujikura, Toshio; Hiraoka, Toshio; Tenou, Hiromi.

    1983-06-01

    The herbicide, paraquat (methyl viologen, 1-1' dimethy1-4, 4'-bipyridinium dichloride), stimulates the production of superoxide anion (O 2 sup(-.)) in aerobic cells and therefore mimics some effects of ionizing radiation. In addition, concentrations of cellular glutathione are reduced by reaction with O 2 sup(-.). It is reported here that paraquat, toxic in its own right to aerobic cells, acts as a radiosensitizer when cells are exposed to nontoxic concentrations of the drug prior to and during irradiation. The radiomimetic effect of paraquat, alone and in combination with X-rays, was examined. Paraquat affects aerated cells (hamster lung V79 cells) in a dose-dependent manner. Doses in excess of 1 mM for two hours cause significant cell killing. In combination with radiation, sublethal doses of paraquat, given for two hours prior to irradiation, enhance the lethal effects of radiation. However, if cells are exposed to the same concentration of paraquat following irradiation, no additional lethal effect is observed. Paraquat is a useful tool to study the effects of O 2 sup(-.) and may lead to better understanding of the mechanisms of radiation-induced energy deposition in cells. (author)

  3. Endonuclease IV of Escherichia coli is induced by paraquat

    International Nuclear Information System (INIS)

    Chan, E.; Weiss, B.

    1987-01-01

    The addition of paraquat (methyl viologen) to a growing culture of Escherichia coli K-12 led within 1 hr to a 10- to 20-fold increase in the level of endonuclease IV, a DNase for apurinic/apyrimidinic sites. The induction was blocked by chloramphenicol. Increases of 3-fold or more were also seen with plumbagin, menadione, and phenazine methosulfate. H 2 O 2 produced no more than a 2-fold increase in endonuclease IV activity. The following agents had no significant effect: streptonigrin, nitrofurantoin, tert-butyl hydroperoxide, γ rays, 260-nm UV radiation, methyl methanesulfonate, mitomycin C, and ascorbate. Paraquat, plumbagin, menadione, and phenazine methosulfate are known to generate superoxide radical anions via redox cycling in vivo. A mutant lacking superoxide dismutase was unusually sensitive to induction by paraquat. In addition, endonuclease IV could be induced by merely growing the mutant in pure O 2 . The levels of endonuclease IV in uninduced or paraquat-treated cells were unaffected by mutations of oxyR, a H 2 O 2 -inducible gene that governs an oxidative-stress regulon. The results indicate that endonuclease IV is an inducible DNA-repair enzyme and that its induction can be mediated via the production of superoxide radicals

  4. Endonuclease IV of Escherichia coli is induced by paraquat

    Energy Technology Data Exchange (ETDEWEB)

    Chan, E.; Weiss, B.

    1987-05-01

    The addition of paraquat (methyl viologen) to a growing culture of Escherichia coli K-12 led within 1 hr to a 10- to 20-fold increase in the level of endonuclease IV, a DNase for apurinic/apyrimidinic sites. The induction was blocked by chloramphenicol. Increases of 3-fold or more were also seen with plumbagin, menadione, and phenazine methosulfate. H/sub 2/O/sub 2/ produced no more than a 2-fold increase in endonuclease IV activity. The following agents had no significant effect: streptonigrin, nitrofurantoin, tert-butyl hydroperoxide, ..gamma.. rays, 260-nm UV radiation, methyl methanesulfonate, mitomycin C, and ascorbate. Paraquat, plumbagin, menadione, and phenazine methosulfate are known to generate superoxide radical anions via redox cycling in vivo. A mutant lacking superoxide dismutase was unusually sensitive to induction by paraquat. In addition, endonuclease IV could be induced by merely growing the mutant in pure O/sub 2/. The levels of endonuclease IV in uninduced or paraquat-treated cells were unaffected by mutations of oxyR, a H/sub 2/O/sub 2/-inducible gene that governs an oxidative-stress regulon. The results indicate that endonuclease IV is an inducible DNA-repair enzyme and that its induction can be mediated via the production of superoxide radicals.

  5. Turn-on fluorescence probes based on pyranine/viologen charge-transfer complexes for the determination of nucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Schäferling, Michael, E-mail: Michael.schaeferling@utu.fi; Lang, Thomas; Schnettelker, Annette

    2014-10-15

    The formation of ground state charge-transfer complexes between pyranine (8-hydroxypyrene-1,3,6-trisulfonic acid) and viologen (paraquat) derivatives is utilized for the design of novel fluoroionophores for the determination of phosphate species, particularly of nucleotides. The strong quenching of the pyranine fluorescence by viologen-type charge transfer acceptors can be countermanded if these are functionalized with triethylammonium groups that serve as recognition elements for phosphate anions. We report on the fluorogenic responses of these water-soluble molecular probes in presence of different phosphates. Absorbance measurements give additional information on the charge transfer complex formation and the interaction with nucleotides. The experimental data show that these aggregates form attractive, simple and versatile fluorescence turn-on probes for nucleoside triphosphates. The reversibility of the fluorescence response is demonstrated by means of an enzymatic model assay using ATPase for the decomposition of adenosine triphosphate. - Highlights: • Pyranine/viologen charge-transfer complexes as molecular probe for ATP recognition. • Fluorescence turn on mechanism. • Selective compared to other nucleotides and phosphate anions. • Fast and reversible response applicable to monitor enzymatic reactions.

  6. Paraquat poisoning in the dog

    International Nuclear Information System (INIS)

    O'Sullivan, S.P.

    1989-01-01

    Recovery from paraquat poisoning in the dog is rare. This is a report of a case of recovery from confirmed paraquat poisoning in a clinical setting. The dog exhibited the usual signs of paraquat poisoning. The diagnosis was confirmed on toxicological analysis of urine using an ion exchange technique. The dog was treated with frusemide, nicotinamide, corticosteroids, α-tocopherol, vitamin A, etamiphylline camsylate and ampicillin. He recovered after seven weeks of intensive therapy. Alternative treatments are discussed

  7. Electrochromic mirror using viologen-anchored nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Han Na [Electronics and Telecommunications Research Institute, Nature-mimic I/O interface Research Section, 218 Gajeong-roYuseong-gu, Daejeon 305-700 (Korea, Republic of); University of Science and Technology, Advanced Device Technology, 217 Gajeong-roYuseong-gu, Daejeon 305-350 (Korea, Republic of); Cho, Seong M.; Ah, Chil Seong; Song, Juhee; Ryu, Hojun; Kim, Yong Hae [Electronics and Telecommunications Research Institute, Nature-mimic I/O interface Research Section, 218 Gajeong-roYuseong-gu, Daejeon 305-700 (Korea, Republic of); Kim, Tae-Youb, E-mail: youby@etri.re.kr [Electronics and Telecommunications Research Institute, Nature-mimic I/O interface Research Section, 218 Gajeong-roYuseong-gu, Daejeon 305-700 (Korea, Republic of); University of Science and Technology, Advanced Device Technology, 217 Gajeong-roYuseong-gu, Daejeon 305-350 (Korea, Republic of)

    2016-10-15

    Highlights: • Three types of ECM device were fabricated using viologen-anchored ECDs. • The devices were investigated according to their optical structures. • The anti-reflection material affects the reflectance and the coloration efficiency. • The device design of ECMs is a crucial factor for clear reflected images. - Abstract: Electrochromic mirrors (ECMs) that are used in automobile mirrors need to have high reflectance, a high contrast ratio, and a clear image. In particular, it is critical that distortions of clear images are minimized for safety. Therefore, an ECM is fabricated using viologen-anchored nanoparticles and a magnesium fluoride (MgF{sub 2}) layer with an anti-reflection function. The ECM has approximately 30.42% in the reflectance dynamic range and 125 cm{sup 2}/C high coloration efficiency.

  8. Paraquat: A fatal poison

    Directory of Open Access Journals (Sweden)

    J Shashibhushan

    2015-01-01

    Full Text Available Paraquat (1, 1′-dimethyl-4, 4′-dipyridylium is a bipyridilium herbicide used widely in our country and is a highly toxic compound. This compound is very notorious to cause rapid development of renal, liver, and respiratory failure with very high mortality due to lack of specific antidote and dearth of high-quality evidence-based treatment. Respiratory system involvement is the most common cause of death in these people. We hereby report a fatal case of a 30-year-old male with a history of paraquat consumption. The patient developed oliguric renal failure, deterioration of liver function, and acute respiratory distress syndrome over next few days. Different treatment modalities were tried to manage patient′s condition. In this case, none of the strategies worked well, and death ensued due to multi-organ dysfunction syndrome.

  9. Photoreduction of viologen with (Zn-TPPS/sub 3/)/sup 3 -/. Triethanolamine- viologen system in the presence of micelles

    Energy Technology Data Exchange (ETDEWEB)

    Kita, Tatsuya; Okura, Ichiro

    1988-04-10

    Photoreduction of viologen was made in the presence of various surfactant micelles by irradading a trinary system of triethanol-amine, zinc meso-tetraphenylporphyrintrisulfonate ; (Zn-TPPS/sub 3/)/sup 3 -/, and viologen with the visible light. Although the rate of photoreduction of viologen was remarkably increased in the presence of either cationic or anionic micelles, it is not noticeably increased in the presence of neutral ones. The elementary reactions were measured by the laser flashing method. The elementary reactions were measured by the laser flashing method. The result indicates that the presence of ionic micelles retards both the quenching reaction of photoexcited (Zn-TPPS/sub 3/)/sup 3 -/ by viologen and the recombination reaction of the oxidative (Zn-TPPS/sub 3/)/sup 3 -/ with the reductive viologen and that the rate of reduction of viologen is much increased by the retardation of the recombination reaction. (6 figs, 1 tab, 16 refs)

  10. 77 FR 47539 - Paraquat Dichloride; Pesticide Tolerances

    Science.gov (United States)

    2012-08-09

    ... effects of paraquat. The effects of paraquat in lungs are considered systemic effects. There are no dermal toxicity studies suitable for evaluation of systemic lung effects in the toxicity database for paraquat... (PAM) Vol. II, is available for enforcing tolerances for residues of paraquat in/on plant commodities...

  11. Interaction between viologen-phosphorus dendrimers and α-synuclein

    International Nuclear Information System (INIS)

    Milowska, Katarzyna; Grochowina, Justyna; Katir, Nadia; El Kadib, Abdelkrim; Majoral, Jean-Pierre; Bryszewska, Maria; Gabryelak, Teresa

    2013-01-01

    In this study the interaction between viologen-phosphorus dendrimers and α-synuclein (ASN) was examined. Polycationic viologen-phosphorus dendrimers (two positive charges per viologen unit) are novel compounds with relatively unknown properties. The influence of these viologen dendrimers on ASN was tested using fluorimetric and circular dichroism methods. ASN contains four tyrosine residues; therefore, the influence of dendrimers on protein molecular conformation by measuring the changes in the ASN fluorescence in the presence of dendrimers was evaluated. The interaction of dendrimers with free L-tyrosine was also monitored. Results show that viologen-phosphorus dendrimers interact with ASN; they quenched the fluorescence of ASN as well as free tyrosine by dynamic and static ways. However, the quenching was not accompanied by modifications in the ASN secondary structure. - Highlights: ► Interaction between viologen-phosphorus dendrimers and α-synuclein (ASN) was investigated. ► Viologen-phosphorus dendrimers can quench the fluorescence of tyrosine in ASN. ► Dendrimers caused red-shift in maximum of fluorescence. ► Viologen-phosphorus dendrimers did not change the secondary structure of ASN.

  12. Interaction between viologen-phosphorus dendrimers and {alpha}-synuclein

    Energy Technology Data Exchange (ETDEWEB)

    Milowska, Katarzyna, E-mail: milowska@biol.uni.lodz.pl [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz (Poland); Grochowina, Justyna [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz (Poland); Katir, Nadia [Laboratoire de Chimie de Coordination CNRS, 205 route de Narbonne, 31077 Toulouse (France); El Kadib, Abdelkrim [Institute of Nanomaterials and Nanotechnology (INANOTECH)-MAScIR (Moroccan Foundation for Advanced Science, Innovation and Research), ENSET, Avenue de I' Armee Royale, Madinat El Irfane, 10100 Rabat (Morocco); Majoral, Jean-Pierre [Laboratoire de Chimie de Coordination CNRS, 205 route de Narbonne, 31077 Toulouse (France); Bryszewska, Maria; Gabryelak, Teresa [Department of General Biophysics, Faculty of Biology and Environmental Protection, University of Lodz, Pomorska 141/143, 90-236 Lodz (Poland)

    2013-02-15

    In this study the interaction between viologen-phosphorus dendrimers and {alpha}-synuclein (ASN) was examined. Polycationic viologen-phosphorus dendrimers (two positive charges per viologen unit) are novel compounds with relatively unknown properties. The influence of these viologen dendrimers on ASN was tested using fluorimetric and circular dichroism methods. ASN contains four tyrosine residues; therefore, the influence of dendrimers on protein molecular conformation by measuring the changes in the ASN fluorescence in the presence of dendrimers was evaluated. The interaction of dendrimers with free L-tyrosine was also monitored. Results show that viologen-phosphorus dendrimers interact with ASN; they quenched the fluorescence of ASN as well as free tyrosine by dynamic and static ways. However, the quenching was not accompanied by modifications in the ASN secondary structure. - Highlights: Black-Right-Pointing-Pointer Interaction between viologen-phosphorus dendrimers and {alpha}-synuclein (ASN) was investigated. Black-Right-Pointing-Pointer Viologen-phosphorus dendrimers can quench the fluorescence of tyrosine in ASN. Black-Right-Pointing-Pointer Dendrimers caused red-shift in maximum of fluorescence. Black-Right-Pointing-Pointer Viologen-phosphorus dendrimers did not change the secondary structure of ASN.

  13. Biological properties of new viologen-phosphorus dendrimers.

    Science.gov (United States)

    Ciepluch, Karol; Katir, Nadia; El Kadib, Abdelkrim; Felczak, Aleksandra; Zawadzka, Katarzyna; Weber, Monika; Klajnert, Barbara; Lisowska, Katarzyna; Caminade, Anne-Marie; Bousmina, Mostapha; Bryszewska, Maria; Majoral, Jean Pierre

    2012-03-05

    Some biological properties of eight dendrimers incorporating both phosphorus linkages and viologen units within their cascade structure or at the periphery were investigated for the first time. In particular cytotoxicity, hemotoxicity, and antimicrobial and antifungal activity of these new macromolecules were examined. Even if for example all these species exhibited good antimicrobial properties, it was demonstrated that their behavior strongly depends on several parameters as their size and molecular weight, the number of viologen units and the nature of the terminal groups.

  14. Paraquat use among farmers in Korea after the ban.

    Science.gov (United States)

    Bang, Ye Jin; Kim, Jaeyoung; Lee, Won Jin

    2017-07-04

    The purpose of this study was to examine the proportion of paraquat use among farmers and to describe their epidemiologic characteristics after the paraquat ban in 2012. We interviewed 249 farmers in Korea in 2014. Approximately 20% of the farmers reported using paraquat in 2014. Farmers with longer farming experience, longer pesticide application years, and upland farming reported an increased risk of paraquat use although the trend was not statistically significant. The majority of the farmers used preexisting paraquat (85.7%), but some farmers purchased it illegally (14.3%). Farmers who used paraquat perceived paraquat as a dangerous chemical; however, they disagreed with the necessity of the paraquat ban.

  15. Binding of paraquat to cell walls of paraquat resistant and susceptible biotypes of Hordeum glaucum

    International Nuclear Information System (INIS)

    Alizadeh, H.M.; Preston, C.; Powles, S.B.

    1997-01-01

    Full text: Paraquat is a widely used, non-selective, light activated contact herbicide acting as a photosystem electron acceptor. Resistance to paraquat in weed species has occurred in Australia and world-wide following extensive use of this herbicide. The mechanism of resistance to paraquat in 'Hordeum glaucum' is correlated with reduced herbicide translocation and may be due to sequestration of herbicide away from its site of action by either binding to cell walls or other means. We measured paraquat binding to a cell wall fraction in resistant and susceptible biotypes of H. glaucum to determine whether differences in binding of paraquat to cell walls could explain herbicide resistance. The cell wall fraction was isolated from leaves of resistant and susceptible biotypes and incubated with 14 C-labelled paraquat. Of the total paraquat - absorbed by a cell wall preparation, about 80% remains strongly bind to the cell wall and doesn't readily exchange with solution in the absence of divalent cations. Divalent cations (Ca 2+ ,putrescine and paraquat) can competitively exchange for paraquat tightly bound to the cell wall. From kinetic experiments it seems that there are two types of binding sites in the cell wall with different affinities for paraquat. No significant differences between cell wall, characteristics of resistant and susceptible biotypes of H. glaucum have been found in any of our experiments. Therefore, increased binding of paraquat to the cell wall appears not to be a mechanism for exclusion of paraquat in resistant biotype

  16. Viologen-Phosphorus Dendrimers Inhibit α-Synuclein Fibrillation.

    Science.gov (United States)

    Milowska, Katarzyna; Grochowina, Justyna; Katir, Nadia; El Kadib, Abdelkrim; Majoral, Jean-Pierre; Bryszewska, Maria; Gabryelak, Teresa

    2013-03-04

    Inhibition of α-synuclein (ASN) fibril formation is a potential therapeutic strategy in Parkinson's disease and other synucleinopathies. The aim of this study was to examine the role of viologen-phosphorus dendrimers in the α-synuclein fibrillation process and to assess the structural changes in α-synuclein under the influence of dendrimers. ASN interactions with phosphonate and pegylated surface-reactive viologen-phosphorus dendrimers were examined by measuring the zeta potential, which allowed determining the number of dendrimer molecules that bind to the ASN molecule. The fibrillation kinetics and the structural changes were examined using ThT fluorescence and CD spectroscopy. Depending on the concentration of the used dendrimer and the nature of the reactive groups located on the surface, ASN fibrillation kinetics can be significantly reduced, and even, in the specific case of phosphonate dendrimers, the fibrillation can be totally inhibited at low concentrations. The presented results indicate that viologen-phosphorus dendrimers are able to inhibit ASN fibril formation and may be used as fibrillar regulating agents in neurodegenerative disorders.

  17. Radiochromic film containing methyl viologen for radiation dosimetry

    DEFF Research Database (Denmark)

    Lavalle, M.; Corda, U.; Fuochi, P.G.

    2007-01-01

    Poly(vinyl alcohol) (PVA) films containing methyl viologen (MV2+) that colours blue upon exposure to ionizing radiation were investigated as possible dosimeters for use in radiation processing applications. In order to find the most suitable composition of the PVA-MV2+ film, different......, humidity and temperature on the response of the PVA-MV2+ dosimeter film have been studied under laboratory conditions. We conclude that the PVA film containing MV2+ is a promising tool for the absorbed dose measurements in several industrial applications of ionizing radiations. (C) 2007 Elsevier Ltd. All...

  18. Acute kidney injury from Paraquat poisoning: a case report. | Slater ...

    African Journals Online (AJOL)

    Acute kidney injury from Paraquat poisoning: a case report. H. E. Slater, O.C.A. Okoye, O. Okperi, N. Rajora. Abstract. Paraquat is a salt widely used as a herbicide. Although paraquat poisoning is rare in the general population, it may be considered as one of the most toxic poisons frequently used for suicide attempts, and is ...

  19. The autoradiographic localization of paraquat in the lung

    International Nuclear Information System (INIS)

    Webb, D.B.

    1980-01-01

    Paraquat poisoning in mammals results in a characteristic lung lesion manifested principally as progressive pulmonary fibrosis. Paraquat is actively concentrated into the lung but the site of uptake remains undefined. A method is described for the autoradiographic localization of paraquat in rats. Preliminary evidence for the site of uptake implicates the bronchiol. (author)

  20. Early Pulomonary Irradiation in Paraquat (Gramoxone) Poisoning

    International Nuclear Information System (INIS)

    Lee, Chang Geol; Kim, Gwi Eon; Suh, Chang Ok

    1995-01-01

    Purpose : To evaluate whether the early pulmonary irradiation can prevent or decrease the pulmonary damage and contribute to improve ultimate survival in paraquat lung. Materials and Methods : From Jun. 1987 to Aug. 1993, thirty patients with paraquat poisoning were evaluated. Fourteen of these patients were received pulmonary irradiation(RT). All of the patients ere managed with aggressive supportive treatment such as gastric lavage, forced diuresis, antioxidant agents and antifibrosis agents. Ingested amounts of paraquat were estimated into three groups(A: minimal 50cc). Pulmonary irradiation was started within 24 hours after admission(from day 1 to day 11 after ingestion of paraquat). Both whole lungs were irradiated with AP/PA parallel opposing fields using C0-60 teletherapy machine. A total of 10Gy(2Gy/fr. X 5 days)was delivered without correction of lung density. Results : In group A, all patients were alive regardless of pulmonary irradiation and in group C, all of the patients were died due o multi-organ failure, especially pulmonary fibrosis regardless of pulmonary irradiation. However, in group B, six of 7 patients(86%) with no RT were died due to respiratory failure, but 4 of 8 patients with RT were alive and 4 of 5 patients who received pulmonary irradiation within 4 days after ingestion of paraquat were all alive though radiological pulmonary fibrosis. All 3 patients who were received pulmonary irradiation after 4 days after ingestion were died due to pulmonary fibrosis in spite of recovery from renal and hepatic toxicity. Conclusion : It is difficult to find out the effect of pulmonary irradiation on the course of the paraquat lung because the precise plasma and urine paraquat concentration were not available between control and irradiation groups. But early pulmonary irradiation within 4 days after paraquat poisoning with aggressive supportive treatment appears to decrease pulmonary toxicity and contribute survival in patients with mouthful ingestion

  1. Removal of paraquat solution onto zeolite material

    Science.gov (United States)

    Sirival, Rujikarn; Patdhanagul, Nopbhasinthu; Preecharram, Sutthidech; Photharin, Somkuan

    2018-04-01

    The purpose of this research was to study the adsorption of paraquat herbicides onto zeolite Y materials by the batch method. Three adsorbents material: Zeolite-3, Zeolite-10, and Zeolite-100 were Si/Al ratio at 3.58, 8.57 and 154.37, respectively. The factors for adsorption of paraquat as follows, adsorption time, initial concentrations of paraquat, pH and adsorption isotherm were investigated. The results showed that zeolite-10 had higher adsorption capacity than zeolite-3 and zeolite-100. The appropriate conditions for adsorption were 24 h., Zeolite 0.1 g., Initial paraquat concentration 100 ppm at pH 6. The adsorption isotherm was found to correspond with Langmuir Isotherm and the maximum paraquat adsorption is 26.38 mg/g for zeolite-10, 21.41 mg/g and 9.60 mg/g for zeolite-3 and zeolite-100, respectively. The characterization of zeolite material with XRD, XRF and BET. Furthermore, the zeolite materials applied to remove other organic and inorganic wastewater.

  2. Chest radiographic findings in acute paraquat poisoning

    Energy Technology Data Exchange (ETDEWEB)

    Na, Gyeong Gyun; Lee, Mi Sook; Kim, Hee Jun; Sun, In O [Presbyterian Medical Center, Jeonju (Korea, Republic of)

    2016-01-15

    To describe the chest radiographic findings of acute paraquat poisoning. 691 patients visited the emergency department of our hospital between January 2006 and October 2012 for paraquat poisoning. Of these 691, we identified 56 patients whose initial chest radiographs were normal but who developed radiographic abnormalities within one week. We evaluated their radiographic findings and the differences in imaging features based on mortality. The most common finding was diffuse consolidation (29/56, 52%), followed by consolidation with linear and nodular opacities (18/56, 32%), and combined consolidation and pneumomediastinum (7/56, 13%). Pleural effusion was noted in 17 patients (30%). The two survivors (4%) showed peripheral consolidations, while the 54 patients (96%) who died demonstrated bilateral (42/54, 78%) or unilateral (12/54, 22%) diffuse consolidations. Rapidly progressing diffuse pulmonary consolidation was observed within one week on follow-up radiographs after paraquat ingestion in the deceased, but the survivors demonstrated peripheral consolidation.

  3. Paraquat: model for oxidant-initiated toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Bus, J.S.; Gibson, J.E.

    1984-04-01

    Paraquat, a quaternary ammonium bipyridyl herbicide, produces degenerative lesions in the lung after systemic administration to man and animals. The pulmonary toxicity of paraquat resembles in several ways the toxicity of several other lung toxins, including oxygen, nitrofurantoin and bleomycin. Although a definitive mechanism of toxicity of parquat has not been delineated, a cyclic single electron reduction/oxidation of the parent molecule is a critical mechanistic event. The redox cycling of paraquat has two potentially important consequences relevant to the development of toxicity: generation of activated oxygen (e.g., superoxide anion, hydrogen perioxide, hydroxyl radical) which is highly reactive to cellular macromolecules; and/or oxidation of reducing equivalents (e.g., NADPH, reduced glutathione) necessary for normal cell function. Paraquat-induced pulmonary toxicity, therefore, is a potentially useful model for evaluation of oxidant mechanisms of toxicity. Furthermore, characterization of the consequences of intracellular redox cycling of xenobiotics will no doubt provide basic information regarding the role of this phenomena in the development of chemical toxicity. 105 references, 2 figures.

  4. Porphyrinic supramolecular daisy chains incorporating pillar[5]arene-viologen host-guest interactions

    KAUST Repository

    Fathalla, Maher; Strutt, Nathan; Srinivasan, Sampath; Katsiev, Khabiboulakh; Hartlieb, Karel J.; Bakr, Osman; Stoddart, J. Fraser

    2015-01-01

    A porphyrin functionalised with pillar[5]arene and a viologen at its 5- and 15-meso positions assembles in a head-to-tail manner, producing linear supramolecular daisy chains in dichloromethane. At high concentrations, it forms an organogel which has been investigated by electron microscopy and rheological measurements, paving the way for the preparation of other functional supramolecular assemblies which harness viologen"⊂" pillararene host-guest interactions.

  5. Porphyrinic supramolecular daisy chains incorporating pillar[5]arene-viologen host-guest interactions

    KAUST Repository

    Fathalla, Maher

    2015-05-18

    A porphyrin functionalised with pillar[5]arene and a viologen at its 5- and 15-meso positions assembles in a head-to-tail manner, producing linear supramolecular daisy chains in dichloromethane. At high concentrations, it forms an organogel which has been investigated by electron microscopy and rheological measurements, paving the way for the preparation of other functional supramolecular assemblies which harness viologen"⊂" pillararene host-guest interactions.

  6. Effect of acute paraquat poisoning on CYP450 isoforms activity in rats by cocktail method

    OpenAIRE

    Wang, Shuanghu; Wang, Zhiyi; Chen, Dongxin; Chen, Mengchun; Lin, Yingying; Liu, Zezheng; Zhang, Lijing; Wen, Congcong; Wang, Xianqin; Ma, Jianshe

    2015-01-01

    Paraquat is a highly effective contact herbicide that is marketed worldwide as a fantastical, non-selective compound for broadleaf weed control. As compared to most pesticides, paraquat is extremely toxic to humans and the lack of strategies to manage paraquat poisoning has resulted in high fatality rates. The rats were randomly divided into acute paraquat poisoning group and control group. The paraquat group rats were given 36 mg/kg paraquat by intragastric administration. The influence of a...

  7. Photo-physical and structural interactions between viologen phosphorus-based dendrimers and human serum albumin

    International Nuclear Information System (INIS)

    Ciepluch, Karol; Katir, Nadia; El Kadib, Abdelkrim; Weber, Monika; Caminade, Anne-Marie; Bousmina, Mostapha; Pierre Majoral, Jean; Bryszewska, Maria

    2012-01-01

    This work deals with photo-physical and structural interactions between viologen phosphorus dendrimers and human serum albumin (HSA). Viologens are derivatives of 4,4′-bipyridinium salts. Aiming to rationalize the parameters governing such interactions eight types of these polycationic dendrimers in which the generation, the number of charges, the nature of the core and of the terminal groups vary from one to another, were designed and used. The influence of viologen-based dendrimers' on human serum albumin has been investigated. The photo-physical interactions of the two systems have been monitored by fluorescence quenching of free L-tryptophan and of HSA tryptophan residue. Additionally, using circular dichroism (CD) the effect of dendrimers on the secondary structure of albumin was measured. The obtained results show that viologen dendrimers interact with human serum albumin quenching its fluorescence either by collisional (dynamic) way or by forming complexes in a ground state (static quenching). In some cases the quenching is accompanied by changes of the secondary structure of HSA. - Highlights: ► Photo-physical interactions between viologen phosphorus dendrimers and human serum albumin (HSA) were investigated. ► The viologen dendrimers can quench the fluorescence of tryptophan in HSA. ► CD spectra to explain the changes in secondary structure of albumin after exposition of dendrimers.

  8. Photo-physical and structural interactions between viologen phosphorus-based dendrimers and human serum albumin

    Energy Technology Data Exchange (ETDEWEB)

    Ciepluch, Karol, E-mail: ciepluch@biol.uni.lodz.pl [Department of General Biophysics, University of Lodz, 141/143 Pomorska St., 90-236 Lodz (Poland); Katir, Nadia [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 route de Narbonne, F-31077 Toulouse cedex 4 (France); Institute of Nanomaterials and Nanotechnology (INANOTECH)-MAScIR (Moroccan Foundation for Advanced Science, Innovation and Research), ENSET, Avenue de l' Armee Royale, Madinat El Irfane, 10100 Rabat (Morocco); El Kadib, Abdelkrim [Institute of Nanomaterials and Nanotechnology (INANOTECH)-MAScIR (Moroccan Foundation for Advanced Science, Innovation and Research), ENSET, Avenue de l' Armee Royale, Madinat El Irfane, 10100 Rabat (Morocco); Weber, Monika [Department of General Biophysics, University of Lodz, 141/143 Pomorska St., 90-236 Lodz (Poland); Caminade, Anne-Marie [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 route de Narbonne, F-31077 Toulouse cedex 4 (France); Bousmina, Mostapha [Hassan II Academy of Sciences and Technology, Avenue MVI, Km4, 10220 Rabat (Morocco); Pierre Majoral, Jean [Laboratoire de Chimie de Coordination du CNRS (LCC), 205 route de Narbonne, F-31077 Toulouse cedex 4 (France); Hassan II Academy of Sciences and Technology, Avenue MVI, Km4, 10220 Rabat (Morocco); Bryszewska, Maria [Department of General Biophysics, University of Lodz, 141/143 Pomorska St., 90-236 Lodz (Poland)

    2012-06-15

    This work deals with photo-physical and structural interactions between viologen phosphorus dendrimers and human serum albumin (HSA). Viologens are derivatives of 4,4 Prime -bipyridinium salts. Aiming to rationalize the parameters governing such interactions eight types of these polycationic dendrimers in which the generation, the number of charges, the nature of the core and of the terminal groups vary from one to another, were designed and used. The influence of viologen-based dendrimers' on human serum albumin has been investigated. The photo-physical interactions of the two systems have been monitored by fluorescence quenching of free L-tryptophan and of HSA tryptophan residue. Additionally, using circular dichroism (CD) the effect of dendrimers on the secondary structure of albumin was measured. The obtained results show that viologen dendrimers interact with human serum albumin quenching its fluorescence either by collisional (dynamic) way or by forming complexes in a ground state (static quenching). In some cases the quenching is accompanied by changes of the secondary structure of HSA. - Highlights: Black-Right-Pointing-Pointer Photo-physical interactions between viologen phosphorus dendrimers and human serum albumin (HSA) were investigated. Black-Right-Pointing-Pointer The viologen dendrimers can quench the fluorescence of tryptophan in HSA. Black-Right-Pointing-Pointer CD spectra to explain the changes in secondary structure of albumin after exposition of dendrimers.

  9. Photoinduced Charge Shifts and Electron Transfer in Viologen-Tetraphenylborate Complexes: Push-Pull Character of the Exciplex.

    Science.gov (United States)

    Santos, Willy G; Budkina, Darya S; Deflon, Victor M; Tarnovsky, Alexander N; Cardoso, Daniel R; Forbes, Malcolm D E

    2017-06-14

    Viologen-tetraarylborate ion-pair complexes were prepared and investigated by steady-state and time-resolved spectroscopic techniques such as fluorescence and femtosecond transient absorption. The results highlight a charge transfer transition that leads to changes in the viologen structure in the excited singlet state. Femtosecond transient absorption reveals the formation of excited-state absorption and stimulated emission bands assigned to the planar (k obs < 10 12 s -1 ) and twisted (k obs ∼ 10 10 s -1 ) structures between two pyridinium groups in the viologen ion. An efficient photoinduced electron transfer from the tetraphenylborate anionic moiety to the viologen dication was observed less than 1 μs after excitation. This is a consequence of the push-pull character of the electron donor twisted viologen structure, which helps formation of the borate triplet state. The borate triplet state is deactivated further via a second electron transfer process, generating viologen cation radical (V •+ ).

  10. A high constitutive catalase activity confers resistance to methyl viologen-promoted oxidative stress in a mutant of the cyanobacterium Nostoc punctiforme ATCC 29133.

    Science.gov (United States)

    Moirangthem, Lakshmipyari Devi; Bhattacharya, Sudeshna; Stensjö, Karin; Lindblad, Peter; Bhattacharya, Jyotirmoy

    2014-04-01

    A spontaneous methyl viologen (MV)-resistant mutant of the nitrogen-fixing cyanobacterium Nostoc punctiforme ATCC 29133 was isolated and the major enzymatic antioxidants involved in combating MV-induced oxidative stress were evaluated. The mutant displayed a high constitutive catalase activity as a consequence of which, the intracellular level of reactive oxygen species in the mutant was lower than the wild type (N. punctiforme) in the presence of MV. The superoxide dismutase (SOD) activity that consisted of a SodA (manganese-SOD) and a SodB (iron-SOD) was not suppressed in the mutant following MV treatment. The mutant was, however, characterised by a lower peroxidase activity compared with its wild type, and its improved tolerance to externally added H₂O₂ could only be attributed to enhanced catalase activity. Furthermore, MV-induced toxic effects on the wild type such as (1) loss of photosynthetic performance assessed as maximal quantum yield of photosystem II, (2) nitrogenase inactivation, and (3) filament fragmentation and cell lysis were not observed in the mutant. These findings highlight the importance of catalase in preventing MV-promoted oxidative damage and cell death in the cyanobacterium N. punctiforme. Such oxidative stress resistant mutants of cyanobacteria are likely to be a better source of biofertilisers, as they can grow and fix nitrogen in an unhindered manner in agricultural fields that are often contaminated with the herbicide MV, also commonly known as paraquat.

  11. Efectos del herbicida Paraquat sobre el zooplancton Effects of Paraquat herbicide on zooplankton

    Directory of Open Access Journals (Sweden)

    Ana María Gagneten

    2002-09-01

    Full Text Available The effects of 0.1; 0.2; 0.4 and 0.8 mlPQ/L were analized on a zooplankton community, to determine the most sensitive species and to analize the occurence of physical abnormalities. A total of 40 taxa were determined. Paraquat affected significantly the zooplankton density but not the species richness. A progressive state of deformation of these organisms was also observed. Paraquat showed to be highly toxic for the zooplankton, so this herbicide should be strictly regulated in aquatic and terrestrial ecosystems.

  12. A new repeatable, optical writing and electrical erasing device based on photochromism and electrochromism of viologen

    International Nuclear Information System (INIS)

    Gao, Li-ping; Wei, Jian; Wang, Yue-chuan; Ding, Guo-jing; Yang, Yu-lin

    2012-01-01

    New optical writing and electrical erasing devices have been successfully fabricated that exploit the photochromism and electrochromism of viologen. In a preliminary study, both the structures of viologen and device were investigated in detail by UV–vis spectra in order to confirm their effects on the optical writing and electrical erasing performances of corresponding devices. For sandwiched, single and complementary devices based on benzyl viologen (BV 2+ ), only optical writing can be performed, not electrical erasing operations, which indicated these devices cannot realize optical information rewriting. For single and complementary devices based on styrene-functional viologen (V BV 2+ ) and acrylic-functional viologen (ACV 2+ ), optical writing and electrical erasing operations can be reversibly performed and optical information rewriting realized. It is clear that single devices based on V BV 2+ and ACV 2+ possess better performance accompanied with contrast without significant degradation and bleaching times and without significant deterioration over 10 repeated writing/erasing cycles. Furthermore, we put forward possible mechanisms for sandwiched, single and complementary devices based on V BV 2+ and ACV 2+ for the optical writing and electrical erasing operations. This study provides a new strategy to design optical writing and electrical erasing devices to realize optical information rewriting. (paper)

  13. Melatonin: a protective and detoxifying agent in paraquat toxicity

    International Nuclear Information System (INIS)

    Ghanem, M.; Gad, H.; Hanan; Aziz, A.; Nasr, M.

    2002-01-01

    The ability of melatonin as a protective and detoxifying agent against paraquat-induced oxidative damage in rat lungs and liver was examined. Changes in reduced glutathione (OSH) concentration and malonaldehyde (MDA) level were measured. Pathological examination to lungs and liver was done. Paraquat in 2 doses (20,70 mg/kg) was injected I.P. into rats with melatonin (10 mg/kg) I. P. either before and after paraquat intoxication or only after it. Melatonin proved its protective role when given before and after paraquat intoxication more than its detoxifying effect when given only after paraquat. The biochemical improvement following melatonin therapy was more evident than the histopathological one. (author)

  14. Organic layers at metal/electrolyte interfaces: molecular structure and reactivity of viologen monolayers

    International Nuclear Information System (INIS)

    Breuer, Stephan; Pham, Duc T; Huemann, Sascha; Gentz, Knud; Zoerlein, Caroline; Wandelt, Klaus; Broekmann, Peter; Hunger, Ralf

    2008-01-01

    The adsorption of viologens (1,1'-disubstituted-4,4'-bipyridinium molecules) on a chloride-modified copper electrode has been studied using a combination of cyclic voltammetry (CV), in-situ scanning tunneling microscopy (STM) and ex-situ photoemission spectroscopy (XPS). Two prototypes of viologens could be identified with respect to their redox behavior upon adsorption, namely those which retain (non-reactive adsorption) and those which change their redox state (reactive adsorption) upon interaction with the chloride-modified copper surface at given potential. The first class of viologens represented by 1,1'-dibenzyl-4,4'-bipyridinium molecules (dibenzyl-viologens, abbreviated as DBV) can be adsorbed and stabilized on this electrode surface in their di-cationic state at potentials more positive than the reduction potential of the solution species. XPS N1s core level shifts verify that the adsorbed DBV molecules on the electrode are in their oxidized di-cationic state. Electrostatic attraction between the partially solvated viologen di-cations and the anionic chloride layer is discussed as the main driving force for the DBV stabilization on the electrode surface. Analysis of the N1s and O1s core level shifts points to a non-reactive DBV adsorption leaving the DBV ads 2+ solvation shell partly intact. The laterally ordered DBV ads 2+ monolayer turns out to be hydrophilic with at least four water molecules per viologen present within this cationic organic film. The analysis of the Cl2p core level reveals that no further chloride species are present at the surface besides those which are specifically adsorbed, i.e. which are in direct contact with the metallic copper surface underneath the organic layer. The reduction of these adsorbed DBV ads 2+ surface species takes place only in the same potential regime where the solvated DBV aq 2+ bulk solution species react and is accompanied by a pronounced structural change from the di-cationic 'cavitand'-structure to a

  15. Reversible polycolour change of viologens from violet through transparent to white

    International Nuclear Information System (INIS)

    Hoshino, Katsuyoshi; Oikawa, Yosuke; Sakabe, Ichiro; Komatsu, Toshiki

    2009-01-01

    The electrochromic properties of 1,1'-dibenzyl-4,4'-bipyridinium and 1,1'-diheptyl-4,4'-bipyridinium were investigated in the presence of MBr (M = Li + , Na + , and K + ). The cyclic voltammograms of these viologens showed a white-coloured state in addition to the usual violet one-electron reduction state and the colourless divalent state. Chemical analyses (FT-IR and XPS spectra) of the white film and some control experiments with different supporting electrolytes, MX (X = Cl - and I - ), revealed that the viologens formed water-insoluble ion pairs with tribromide generated by the electrooxidation of monobromide to produce a white film. The film was reversibly decolourized electrochemically to the initial transparent state, providing the polyelectrochromism using the simple viologen/MBr systems. The colouration efficiencies for the violet and the white-coloured states were 170 cm 2 /C and 104 cm 2 /C, respectively.

  16. Effect of viologen-phosphorus dendrimers on acetylcholinesterase and butyrylcholinesterase activities.

    Science.gov (United States)

    Ciepluch, Karol; Weber, Monika; Katir, Nadia; Caminade, Anne-Marie; El Kadib, Abdelkrim; Klajnert, Barbara; Majoral, Jean Pierre; Bryszewska, Maria

    2013-03-01

    The inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) is the first step in checking whether new compounds can be considered as drugs for treating neurodegenerative diseases. The effect of viologen-phosphorus dendrimers on AChE and BChE activities was studied. The results show that the effects on the cholinesterase activities depend on dendrimer type and size. Viologen dendrimers can interact with the enzymes in two ways: they can bind either to a peripheral site of the enzyme or to amino acids located near the active site, inhibiting catalysis by both cholinesterases. All tested non-toxic viologen-phosphorus dendrimers inhibited the activities of both cholinesterases, showing their potential as new drugs for treating neurodegenerative diseases. Copyright © 2012 Elsevier B.V. All rights reserved.

  17. Clinical features and prognosis of paraquat poisoning in French Guiana

    Science.gov (United States)

    Elenga, Narcisse; Merlin, Caroline; Le Guern, Rémi; Kom-Tchameni, Rémi; Ducrot, Yves-Marie; Pradier, Maxime; Ntab, Balthazar; Dinh-Van, Kim-Anh; Sobesky, Milko; Mathieu, Daniel; Dueymes, Jean-Marc; Egmann, Gérald; Kallel, Hatem; Mathieu-Nolf, Monique

    2018-01-01

    Abstract Paraquat is a nonselective contact herbicide of great toxicological importance, being associated with high mortality rates. Because of its high toxicity, the European Union withdrew it from its market in 2007. The aim of this study is to analyze all cases of paraquat poisoning hospitalized in French Guiana in order to assess their incidence and main characteristics. Medical records of all paraquat intoxicated patients hospitalized from 2008 until 2015 were reviewed in this retrospective study. Demographics, clinical presentation, and laboratory data were evaluated. A total of 62 cases were reviewed. The incidence of paraquat poisoning was 3.8/100,000 inhabitants/year. There were 44 adults and 18 children younger than 16 years of age. The median ages were 31 years [18.08–75.25] in adults and 13.4 years [0.75–15.08] in children, respectively. The median duration of hospitalization was longer in children [15.5 days (1–24)] than in adults [2 days (1–30)], P < .01. The majority of cases was due to self-poisoning (84%). Children had ingested a lower quantity of paraquat [48.8 mg/kg (10–571.1)] than adults [595.8 mg/kg (6–3636.4), P = .03]. There were more deaths among adults (65%) than in children (22%), P = .004. The severity and outcome was determined primarily by the amount of paraquat ingested. In conclusion, French Guiana has the largest cohort of paraquat poisonings in the European Union. The major factor affecting the prognosis of patients was the ingested amount of paraquat. The administration of activated charcoal or Pemba, in situ, within the first hour after ingestion of paraquat is essential. PMID:29642226

  18. Possible Appearance of Degradation Products of Paraquat in Crops

    Energy Technology Data Exchange (ETDEWEB)

    Slade, P. [Imperial Chemical Industries LTD., Jealott' s Hill Research Station, Bracknell, Berks. (United Kingdom)

    1966-05-15

    Chemical analysis has established that residue levels of paraquat in crops harvested after use of the chemical are at such a low level as to constitute no hazard to the consuming public. (Paraquat dichloride is 1,1'-dimethyl-4,4'-bipyridylium dichloride). There remained the possibility that toxic metabolites or other conversion products of paraquat might appear in crops. This paper is concerned with attempts to evaluate this possibility, and demonstrates that no hazard arises from the formation of degradation products. It has been shown, using paraquat labelled with {sup 14}C in the methyl groups and in the pyridine nuclei, that the chemical is not metabolically degraded in plants. However, photochemical degradation of paraquat can occur on the surface of leaves in sunlight. In vitro experiments involving ultra-violet irradiation of aqueous solutions of {sup 14}C-paraquat have shown that 4-carboxy-1-methylpyridinium chloride and methylamine hydrochloride are the only products formed in significant amount in the photochemical degradation. Paper chromatography and isotope dilution have shown that these products are formed on leaves of plants treated with {sup 14}C-paraquat (mostly after the plants are dead). Whole plant radioautography has established that 4-carboxy-1-{sup 14}C methylpyridinium chloride is not translocated at all from the dead leaves on which it is formed and certainly this compound will not appear in harvested crops. This has been confirmed in an experiment in which {sup 14}C-paraquat was used to desiccate the tops of potato plants before harvesting the tubers. All the radioactivity subsequently found in the tubers could be accounted for as paraquat (level 0.08 ppm). There was no evidence for the presence of significant amounts of other radioactive compounds in the tubers, even though chromatography of extracts of the desiccated plants showed that photochemical degradation products were formed on the leaves: these were not translocated into the

  19. Hydrogen-Atom Attack on Methyl Viologen in Aqueous Solution Studied by Pulse Radiolysis

    DEFF Research Database (Denmark)

    Solar, S.; Solar, W.; Getoff, N.

    1984-01-01

    Using hydrogen at high pressures of up to 150 bar (0.12 mol dm–3 H2) as an OH scavenger in aqueous MV2+ solutions (pH 1) it is possible to differentiate between two kinds of transient formed simultaneously by H-atom attack on methyl viologen. One of them is assigned to an H adduct on the N atom, ...

  20. [Clinical analysis of lower limb thrombosis caused by paraquat poisoning].

    Science.gov (United States)

    Yu, L J; Jian, X D; Zhang, Z C; Ren, Y L; Ning, Q; Wang, K; Gao, B J; Jia, J E

    2018-01-20

    Objective: To investigate the causes of peripheral vascular thrombosis in patients with paraquat poisoning. Methods: The patients with paraquat poisoning who were admitted to our department in recent two years were observed to screen out the patients with large vessel thrombosis. The data on toxic exposure history, clinical features, and treatment were collected to analyze the causes of thrombosis in the patients with paraquat poisoning. Results: Three patients had typical lower limb thrombosis. There was one case of right common femoral vein thrombosis, one case of bilateral calf muscle vein thrombosis, and one case of right calf superficial vein thrombosis and right calf muscle vein thrombosis. Conclusions: After paraquat poisoning, the blood is in a hypercoagulable state and prolonged bed rest may increase the risk of thrombosis.

  1. Magnetic Hybrid Nanosorbents for the Uptake of Paraquat from Water

    Directory of Open Access Journals (Sweden)

    Tiago Fernandes

    2017-03-01

    Full Text Available Although paraquat has been banned in European countries, this herbicide is still used all over the world, thanks to its low-cost, high-efficiency, and fast action. Because paraquat is highly toxic to humans and animals, there is interest in mitigating the consequences of its use, namely by implementing removal procedures capable of curbing its environmental and health risks. This research describes new magnetic nanosorbents composed of magnetite cores functionalized with bio-hybrid siliceous shells, that can be used to uptake paraquat from water using magnetically-assisted procedures. The biopolymers κ-carrageenan and starch were introduced into the siliceous shells, resulting in two hybrid materials, Fe3O4@SiO2/SiCRG and Fe3O4@SiO2/SiStarch, respectively, that exhibit a distinct surface chemistry. The Fe3O4@SiO2/SiCRG biosorbents displayed a superior paraquat removal performance, with a good fitting to the Langmuir and Toth isotherm models. The maximum adsorption capacity of paraquat for Fe3O4@SiO2/SiCRG biosorbents was 257 mg·g−1, which places this sorbent among the best systems for the removal of this herbicide from water. The interesting performance of the κ-carrageenan hybrid, along with its magnetic properties and good regeneration capacity, presents a very efficient way for the remediation of water contaminated with paraquat.

  2. Literatuuronderzoek naar de bepalingsmetboden an paraquat en diquat in groenten, fruit en andere plantaardige produkten

    NARCIS (Netherlands)

    Lagerwey, W.; Tuinstra, L.G.M.Th.

    1981-01-01

    De resultaten van de literatuurstudie worden samengevat in een overzicht van de bepalingsmetboden van paraquat en diquat in groenten en fruit e.d. Naast de toepassingsgebieden, chemische en fysische eigenschappen van paraquat en diquat werden de bepalingsmethoden bestudeerd. Spektrofotometrische,

  3. Clinical features and prognosis of paraquat poisoning: a review of 41 cases

    OpenAIRE

    Delirrad, Mohammad; Majidi, Mohammad; Boushehri, Behzad

    2015-01-01

    Purpose: Paraquat is a contact herbicide which is highly toxic to human. Deliberate self-poisoning with paraquat continues to be a major public health concern in many developing countries. This study aimed to evaluate the data on cases of acute paraquat poisoning and to compare different variables between survivors and non-survivors. Methods: In this cross sectional study, medical records of all paraquat intoxicated patients were reviewed at Taleghani hospital of Urmia, Iran, from 2007 to 201...

  4. Mechanisms Underlying Early Rapid Increases in Creatinine in Paraquat Poisoning

    Science.gov (United States)

    Mohamed, Fahim; Endre, Zoltan; Jayamanne, Shaluka; Pianta, Timothy; Peake, Philip; Palangasinghe, Chathura; Chathuranga, Umesh; Jayasekera, Kithsiri; Wunnapuk, Klintean; Shihana, Fathima; Shahmy, Seyed; Buckley, Nicholas

    2015-01-01

    Background Acute kidney injury (AKI) is common after severe paraquat poisoning and usually heralds a fatal outcome. The rapid large increases in serum creatinine (Cr) exceed that which can be explained by creatinine kinetics based on loss of glomerular filtration rate (GFR). Methods and Findings This prospective multi-centre study compared the kinetics of two surrogate markers of GFR, serum creatinine and serum cystatin C (CysC), following paraquat poisoning to understand and assess renal functional loss after paraquat poisoning. Sixty-six acute paraquat poisoning patients admitted to medical units of five hospitals were included. Relative changes in creatinine and CysC were monitored in serial blood and urine samples, and influences of non-renal factors were also studied. Results Forty-eight of 66 patients developed AKI (AKIN criteria), with 37 (56%) developing moderate to severe AKI (AKIN stage 2 or 3). The 37 patients showed rapid increases in creatinine of >100% within 24 hours, >200% within 48 hours and >300% by 72 hours and 17 of the 37 died. CysC concentration increased by 50% at 24 hours in the same 37 patients and then remained constant. The creatinine/CysC ratio increased 8 fold over 72 hours. There was a modest fall in urinary creatinine and serum/urine creatinine ratios and a moderate increase in urinary paraquat during first three days. Conclusion Loss of renal function contributes modestly to the large increases in creatinine following paraquat poisoning. The rapid rise in serum creatinine most probably represents increased production of creatine and creatinine to meet the energy demand following severe oxidative stress. Minor contributions include increased cyclisation of creatine to creatinine because of acidosis and competitive or non-competitive inhibition of creatinine secretion. Creatinine is not a good marker of renal functional loss after paraquat poisoning and renal injury should be evaluated using more specific biomarkers of renal injury

  5. Severe paraquat poisoning: clinical and radiological findings in a survivor

    Energy Technology Data Exchange (ETDEWEB)

    Neves, Fabio Fernandes; Sousa, Romualdo Barroso; Pazin-Filho, Antonio; Cupo, Palmira; Elias Junior, Jorge; Nogueira-Barbosa, Marcello Henrique, E-mail: fabioneves@hcrp.usp.b [University of Sao Paulo (USP), Sao Paulo, SP (Brazil). Medical School

    2010-07-01

    Paraquat is a nonselective contact herbicide of great toxicological importance, being associated with high mortality rates, mainly due to respiratory failure. We report the case of a 22-year-old male admitted to the emergency room with a sore throat, dysphagia, hemoptysis, and retrosternal pain after the ingestion of 50 mL of a paraquat solution, four days prior to admission. Chest CT scans revealed pulmonary opacities, pneumomediastinum, pneumothorax, and subcutaneous emphysema. The patient was submitted to two cycles of immunosuppressive therapy with cyclophosphamide, methylprednisolone, and dexamethasone. The pulmonary gas exchange parameters gradually improved, and the patient was discharged four weeks later. The clinical and tomographic follow-up evaluations performed at four months after discharge showed that there had been further clinical improvement. We also present a brief review of the literature, as well as a discussion of the therapeutic algorithm for severe paraquat poisoning. (author)

  6. A facile fluorescent "turn-off" method for sensing paraquat based on pyranine-paraquat interaction

    Science.gov (United States)

    Zhao, Zuzhi; Zhang, Fengwei; Zhang, Zipin

    2018-06-01

    Development of a technically simple yet effective method for paraquat (PQ) detection is of great importance due to its high clinical and environmental relevance. In this study, we developed a pyranine-based fluorescent "turn-off" method for PQ sensing based on pyranine-PQ interaction. We investigated the dependence of analytical performance of this method on the experimental conditions, such as the ion strength, medium pH, and so on. Under the optimized conditions, the method is sensitive and selective, and could be used for PQ detection in real-world sample. This study essentially provides a readily accessible fluorescent system for PQ sensing which is cheap, robust, and technically simple, and it is envisaged to find more interesting clinical and environmental applications.

  7. Effect of Antioxidants on the Outcome of Therapy in Paraquat ...

    African Journals Online (AJOL)

    Erah

    1Department of Anesthesiology and Intensive Care, School of Medicine, 2Isfahan Clinical Toxicology Research. Center, 3Noor ... patients received conventional treatment protocol consisting of fluid replacement, oral absorbents, ... toxic effects via oxidative stress-mediated ... administration of paraquat to rats, the vitamin.

  8. Paraquat poisoning: Acute lung injury – a missed diagnosis ...

    African Journals Online (AJOL)

    Paraquat is a herbicide of great toxicological importance because it is associated with high mortality rates, mainly due to respiratory failure. We report the case of a 28-year-old man admitted to the casualty department at Ngwelezana Hospital, Empangeni, KwaZulu- Natal, South Africa, with a history of vomiting and ...

  9. Paraquat poisoning: Acute lung injury – a missed diagnosis

    African Journals Online (AJOL)

    Paraquat poisoning is frequent in rural and agricultural regions around the world owing to the agricultural use of this compound as a herbicide.[1] It is readily available in agricultural areas of South. Africa (SA), as evident in the case described below. Making a timeous diagnosis and administering appropriate stepwise ...

  10. Structural and spectroscopic properties of the second generation phosphorus-viologen "molecular asterisk".

    Science.gov (United States)

    Furer, V L; Vandukov, A E; Katir, N; Majoral, J P; El Kadib, A; Caminade, A M; Bousmina, M; Kovalenko, V I

    2013-11-01

    The FTIR and FT Raman spectra of the second generation phosphorus-viologen "molecular asterisk" G2 built from cyclotriphosphazene core with 12 viologen units and 6 terminal phosphonate groups have been recorded and analyzed. The experimental X-ray data of 1,1-bis(4-formylbenzyl)-4,4'-bipyridinium bis(hexaflurophosphate) was used in molecular modeling studies. The optimization of isolated 1,1-bis(4-formylbenzyl)-4,4'-bipyridinium (BFBP) molecule without counter ions PF6(-) does not lead to significant changes of dihedral angles, thus the molecular conformation does not depend on interactions with the counter ions. The structural optimization and normal mode analysis were performed for G2 on the basis of the density functional theory (DFT). The calculated geometrical parameters and harmonic vibrational frequencies are predicted in a good agreement with the experimental data. It was found that G2 has a kind of "egg timer" structure with planar OC6H4CHNN(CH3) fragments and slightly non-planar cyclotriphosphazene core. The experimental IR and Raman spectra of G2 were interpreted by means of potential energy distribution. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Paraquat affects mitochondrial bioenergetics, dopamine system expression, and locomotor activity in zebrafish (Danio rerio).

    Science.gov (United States)

    Wang, Xiao H; Souders, Christopher L; Zhao, Yuan H; Martyniuk, Christopher J

    2018-01-01

    The dipyridyl herbicide paraquat induces oxidative stress in cells and is implicated in adult neurodegenerative diseases. However, less is known about paraquat toxicity in early stages of vertebrate development. To address this gap, zebrafish (Danio rerio) embryos were exposed to 1, 10 and 100 μM paraquat for 96 h. Paraquat did not induce significant mortality nor deformity in embryos and larvae, but it did accelerate time to hatch. To evaluate whether mitochondrial respiration was related to earlier hatch times, oxygen consumption rate was measured in whole embryos. Maximal respiration of embryos exposed to 100 μM paraquat for 24 h was reduced by more than 70%, suggesting that paraquat negatively impacts mitochondrial bioenergetics in early development. Based upon this evidence for mitochondrial dysfunction, transcriptional responses of oxidative stress- and apoptosis-related genes were measured. Fish exposed to 1 μM paraquat showed higher expression levels of superoxide dismutase 2, heat shock protein 70, Bcl-2-associated X protein, and B-cell CLL/lymphoma 2a compared to control fish. No differences among groups were detected in larvae exposed to 10 and 100 μM paraquat, suggesting a non-monotonic response. We also measured endpoints related to larval behavior and dopaminergic signaling as paraquat is associated with degeneration of dopamine neurons. Locomotor activity was stimulated with 100 μM paraquat and dopamine transporter and dopamine receptor 3 mRNA levels were increased in larvae exposed to 1 μM paraquat, interpreted to be a compensatory response at lower concentrations. This study improves mechanistic understanding into the toxic actions of paraquat on early developmental stages. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Directed-spray application of paraquat and diuron in physic nut plants

    OpenAIRE

    Costa,N.V.; Neunfeld,T.H.; Ohland,T.; Piano,J.T.; Klein,J.

    2013-01-01

    There is little information about the selectivity of herbicides in physic nut (Jatropha curcas) in Brazil. Therefore, this study aimed to evaluate the selectivity of different doses and mixtures of paraquat and diuron in direted-spray applications in physic nut plants in greenhouse conditions. The study used a randomized block design, with five replicates. The treatments were: paraquat (200 and 600 g ha-1), diuron (1,000 and 2,000 g ha-1), paraquat + diuron (200 + 1,000 g ha-1), paraquat + di...

  13. Ulinastatin suppresses endoplasmic reticulum stress and apoptosis in the hippocampus of rats with acute paraquat poisoning

    Directory of Open Access Journals (Sweden)

    Hai-feng Li

    2015-01-01

    Full Text Available Lung injury is the main manifestation of paraquat poisoning. Few studies have addressed brain damage after paraquat poisoning. Ulinastatin is a protease inhibitor that can effectively stabilize lysosomal membranes, prevent cell damage, and reduce the production of free radicals. This study assumed that ulinastatin would exert these effects on brain tissues that had been poisoned with paraquat. Rat models of paraquat poisoning were intraperitoneally injected with ulinastatin. Simultaneously, rats in the control group were administered normal saline. Hematoxylin-eosin staining showed that most hippocampal cells were contracted and nucleoli had disappeared in the paraquat group. Fewer cells in the hippocampus were concentrated and nucleoli had disappeared in the ulinastatin group. Western blot assay showed that expressions of GRP78 and cleaved-caspase-3 were significantly lower in the ulinastatin group than in the paraquat group. Immunohistochemical findings showed that CHOP immunoreactivity was significantly lower in the ulinastatin group than in the paraquat group. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling staining showed that the number of apoptotic cells was reduced in the paraquat and ulinastatin groups. These data confirmed that endoplasmic reticular stress can be induced by acute paraquat poisoning. Ulinastatin can effectively inhibit this stress as well as cell apoptosis, thereby exerting a neuroprotective effect.

  14. Surfactant 1-Hexadecyl-3-methylimidazolium Chloride Can Convert One-Dimensional Viologen Bromoplumbate into Zero-Dimensional.

    Science.gov (United States)

    Liu, Guangfeng; Liu, Jie; Nie, Lina; Ban, Rui; Armatas, Gerasimos S; Tao, Xutang; Zhang, Qichun

    2017-05-15

    A zero-dimensional N,N'-dibutyl-4,4'-dipyridinium bromoplumbate, [BV] 6 [Pb 9 Br 30 ], with unusual discrete [Pb 9 Br 30 ] 12- anionic clusters was prepared via a facile surfactant-mediated solvothermal process. This bromoplumbate exhibits a narrower optical band gap relative to the congeneric one-dimensional viologen bromoplumbates.

  15. Synthesis of 3-(4,5-dihydroimidazol-1-YL)propyltriethoxysilane bound Ru(II) complex bearing viologen segment

    International Nuclear Information System (INIS)

    Gurbuz, N.; Seckin, T.; Ozdemir, I.; Cetinkaya, B.

    2005-01-01

    The nanostructured metallopolymers consisting of the partially quaternized 3-(4,5-dihydroimidazol-1-yl)propyl having the viologen group linked covalently through the alkyl spacer its Ru(II) complex have been prepared by sol-gel method. Structural elucidation was done with Fourier transform infrared spectroscopy, ultraviolet spectroscopy, and differential thermal analysis (DTA) [ru

  16. Finding of CT and clinical in paraquat poisoning pulmonary injury

    International Nuclear Information System (INIS)

    He Zaifang; Li Hongbing; Cheng Shoulin; Li Qixiang; Huang Zhen; Zeng Jianguo

    2012-01-01

    Objective: To investigate the CT features of pulmonary injury in paraquat poisoning. Methods: The chest CT image of lung injury in 6 cases of paraquat poisoning were analyzed retrospectively. According to different period of poisoning, the 6 cases were divided into 3 types:the early stage of poisoning (within 2 d), the middle stage of poisoning (3-14 d), the late stage of poisoning (>14 d). A comparison between CT signs and the pathological features of patients was made. Results: Among this 6 cases, 3 cases died, 2 cases pulmonary fibrosis was noted, 1 cases recovered. According to different period of poisoning, the 6 cases were divided into 3 stages: in the early stage of poisoning (within 2 d), 3 cases of all patients showed nothing remarkable, 2 cases showed ground-glass opacity, 1 case showed fuzzy lung-marking.In the middle stage of poisoning (3-14 d), all 6 cases showed ground-glass opacity, mosaic attenuation; 6 cases showed pulmonary consolidation; 4 cases showed subpleural lines; 4 cases showed bronchiectasis; 2 cases showed mid-lower pleural effusion. In the late stage of poisoning (>14 d), 4 cases showed pulmonary consolidation and pulmonary fibrosis, 3 cases showed ground-glass opacity and mosaic attenuation, 1 case showed mid-lower pleural effusion; 1 case showed mediastinal emphysema. Conclusion: The clinical pathology process of paraquat poisoning was in line with CT finding which was related with clinical stage and was helpful for clinical assessment of paraquat poisoning promptly and to guide the clinical treatment. (authors)

  17. Voltammetric Quantification of Paraquat and Glyphosate in Surface Waters

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    William Roberto Alza-Camacho

    2016-09-01

    Full Text Available The indiscriminate use of pesticides on crops has a negative environmental impact that affects organisms, soil and water resources, essential for life. Therefore, it is necessary to evaluate the residual effect of these substances in water sources. A simple, affordable and accessible electrochemical method for Paraquat and Glyphosate quantification in water was developed. The study was conducted using as supporting electrolyte Britton-Robinson buffer solution, working electrode of glassy carbon, Ag/AgCl as the reference electrode, and platinum as auxiliary electrode. Differential pulse voltammetry (VDP method for both compounds were validated. Linearity of the methods presented a correlation coefficient of 0.9949 and 0.9919 and the limits of detection and quantification were 130 and 190 mg/L for Paraquat and 40 and 50 mg/L for glyphosate. Comparison with the reference method showed that the electrochemical method provides superior results in quantification of analytes. Of the samples tested, a value of Paraquat was between 0,011 to 1,572 mg/L and for glyphosate it was between 0.201 to 2.777 mg/L, indicating that these compounds are present in water sources and that those may be causing serious problems to human health.

  18. Serum paraquat concentration detected by spectrophotometry in patients with paraquat poisoning

    Science.gov (United States)

    Li, Chang-bin; Li, Xin-hua; Wang, Zhen; Jiang, Cheng-hua; Peng, Ai

    2011-01-01

    BACKGROUND: Paraquat (PQ) is a world-wide used herbicide and also a type of common poison for suicide and accidental poisoning. Numerous studies have proved that the concentration of serum PQ plays an important role in prognosis. Spectrophotometry, including common spectrophotometry and second-derivative spectrophotometry, is commonly used for PQ detection in primary hospitals. So far, lack of systematic research on the reliability of the method and the correlation between clinical features of patients with PQ poisoning and the test results has restricted the clinical use of spectrophotometry. This study aimed to evaluate the reliability and value of spectrophotometry in detecting the concentration of serum PQ. METHODS: The wavelengths for detecting the concentration of serum PQ by common and second-derivative spectrophotometry were determined. Second-derivative spectrophotometry was applied to detect the concentration of serum PQ. The linear range and precision for detection of PQ concentration by this method were confirmed. The concentration of serum PQ shown by second-derivative spectrophotometry and HPLC were compared in 8 patients with PQ poisoning. Altogether 21 patients with acute poisoning 4 hours after PQ ingestion treated in the period of October 2008 to September 2010 were retrospectively reviewed. The patients were divided into higher and lower than 1.8 μg/mL groups based on their concentrations of serum PQ measured by second-derivative spectrophotometry on admission. The severity of clinical manifestations between the two groups were analyzed with Student's t test or Fisher's exact test. RESULTS: The absorption peak of 257 nm could not be found when common spectrophotometry was used to detect the PQ concentration in serum. The calibration curve in the 0.4–8.0 μg/mL range for PQ concentration shown by second-derivative spectrophotometry obeyed Beer's law with r=0.996. The average recovery rates of PQ were within a range of 95.0% to 99.5%, relative

  19. Multiple pathways for uptake of paraquat, methylglyoxal bis(guanylhydrazone), and polyamines

    Energy Technology Data Exchange (ETDEWEB)

    Byers, T.L.; Kameji, R.; Rannels, D.E.; Pegg, A.E.

    1987-06-01

    The uptake of polyamines, methylglyoxal bis(guanylhydrazone) (MGBG), and paraquat (N,N-dimethyl-4,4'-bipyridylium) into control Chinese hamster ovary (CHO) cells and a mutant CHO cell line selected for resistance to the toxicity of MGBG was examined. In contrast to control CHO cells, the mutant cells had no detectable uptake of (/sup 14/C)-MGBG or any of the polyamines. There was no difference between the two cell lines in the uptake of ..cap alpha..-aminoisobutyric (/sup 3/H-AIB), which indicates that there was no general change in membrane transport processes. The mutant cells were also found to be resistant to the toxicity of paraquat and to have a reduced capability to take up the herbicide. This finding confirms that the uptake of paraquat is necessary for the toxicity of this compound and that the paraquat is taken up by a transport system that also transports MGBG. Competition experiments showed that an excess of unlabeled paraquat inhibited uptake of MGBG and, to a lesser extent, uptake of putrescine and spermidine, but no inhibitory action on spermine uptake could be detected. Studies with type II cells isolated from rat lung also demonstrated uptake of paraquat and spermidine, but paraquat was only a weak inhibitor of spermidine uptake in this system. These results suggest that there may be multiple systems for the uptake of MGBG and polyamines and that paraquat is taken up by at least one but not by all of these systems.

  20. Multiple pathways for uptake of paraquat, methylglyoxal bis(guanylhydrazone), and polyamines

    International Nuclear Information System (INIS)

    Byers, T.L.; Kameji, R.; Rannels, D.E.; Pegg, A.E.

    1987-01-01

    The uptake of polyamines, methylglyoxal bis(guanylhydrazone) (MGBG), and paraquat [N,N-dimethyl-4,4'-bipyridylium] into control Chinese hamster ovary (CHO) cells and a mutant CHO cell line selected for resistance to the toxicity of MGBG was examined. In contrast to control CHO cells, the mutant cells had no detectable uptake of [ 14 C]-MGBG or any of the polyamines. There was no difference between the two cell lines in the uptake of α-aminoisobutyric ( 3 H-AIB), which indicates that there was no general change in membrane transport processes. The mutant cells were also found to be resistant to the toxicity of paraquat and to have a reduced capability to take up the herbicide. This finding confirms that the uptake of paraquat is necessary for the toxicity of this compound and that the paraquat is taken up by a transport system that also transports MGBG. Competition experiments showed that an excess of unlabeled paraquat inhibited uptake of MGBG and, to a lesser extent, uptake of putrescine and spermidine, but no inhibitory action on spermine uptake could be detected. Studies with type II cells isolated from rat lung also demonstrated uptake of paraquat and spermidine, but paraquat was only a weak inhibitor of spermidine uptake in this system. These results suggest that there may be multiple systems for the uptake of MGBG and polyamines and that paraquat is taken up by at least one but not by all of these systems

  1. Effets combinés du compost, du Paraquat et de la ...

    African Journals Online (AJOL)

    Ce-PC

    aimed at evaluating the synergistic effects of Paraquat and Lambdacyhalothrin in the presence of the compost .... Paraquat (200 g/l) et la Lambda super 2.5 EC, ..... Enhanced microbial degradation implicated in rapid loss of chlorpyrifos from the controlled release formulation susucon(R) Blue in soil. Crop. Protection,. 17:.

  2. Paraquat toxicity. (Latest citations from the Life Sciences Collection database). Published Search

    Energy Technology Data Exchange (ETDEWEB)

    1993-05-01

    The bibliography contains citations concerning the toxic effects of the herbicide paraquat on humans and animals. Topics include clinical and pathological findings, biochemical mechanisms, effects of oxygen, pulmonary effects of exposure, and effects on freshwater and marine organisms. The contamination of marijuana plants with paraquat is also considered. (Contains 250 citations and includes a subject term index and title list.)

  3. Characterization and comprehension of zeolite NaY/mesoporous SBA-15 composite as adsorbent for paraquat

    Energy Technology Data Exchange (ETDEWEB)

    Osakoo, Nattawut, E-mail: natawut.work@gmail.com [School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000 (Thailand); Pansakdanon, Chaianun [School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000 (Thailand); Department of Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190 (Thailand); Sosa, Narongrit; Deekamwong, Krittanun; Keawkumay, Chalermpan; Rongchapo, Wina [School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000 (Thailand); Chanlek, Narong [Synchrotron Light Research Institute, Nakhon Ratchasima, 30000 (Thailand); Jitcharoen, Juthamas [Department of Chemistry, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani, 34190 (Thailand); Prayoonpokarach, Sanchai [School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000 (Thailand); Wittayakun, Jatuporn, E-mail: jatuporn@g.sut.ac.th [School of Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, 30000 (Thailand)

    2017-06-01

    NaY was synthesized from fumed silica and further modified to form a composite with SBA-15. Textural properties and basicity of the composite NaY-SBA-15 were between those of the parent materials. Paraquat adsorption on NaY was 204.1 mg/g, higher than that on NaY synthesized with rice husk silica from the previous work. SBA-15 was a poor adsorbent for paraquat. Based on the weight of NaY, the adsorption capacity of analytical-grade paraquat on the NaY-SBA-15 composite was 241.5 mg/g-NaY. Moreover, the composite adsorbed blue dye from a commercial grade paraquat. Interaction between the NaY-SBA-15 and paraquat could be from C and N atoms in paraquat with oxygen atom on NaY-SBA-15. - Highlights: • Zeolite NaY/mesoporous SBA-15 composite was synthesized with a simple method. • NaY and SBA-15 coexisted in the composite confirmed by FTIR, CO{sub 2}-TPD and XPS. • Adsorption capacity of paraquat (mg/g-NaY) was improved by NaY and SBA-15 composite. • C and N atoms in paraquat could interact with oxygen atom on NaY-SBA-15 composite.

  4. Thirty-five cases of S-carboxymethylcysteine use in paraquat poisoning.

    Science.gov (United States)

    Lugo-Vallín, Nelly; Maradei-Irastorza, Idania; Pascuzzo-Lima, Carmine; Ramírez-Sánchez, Manuel; Montesinos, Claudia

    2003-02-01

    The herbicide paraquat is associated with a high mortality rate. It produces multiorgan damage through the induction of acute oxidative stress, by generation of reactive oxygen species that cause oxidative damage to biomolecules. In addition to general supportive measures, the management of paraquat poisoning includes gastric washing, forced diuresis, haemodialysis and the use of antioxidants, such as N-acetylcysteine. However, this drug is rather unavailable in Venezuela and S-carboxymethylcysteine has been used. We report 35 patients with mild to severe paraquat poisoning, which beside standard supportive treatment received 1500 mg S-carboxymethylcysteine, up to 2-3 w. The mortality rate was 22.86% (8 deaths/35 cases) and was related to the severity of paraquat poisoning (as assessed by urine dithionite tests). We conclude that S-carboxymethylcysteine is a reliable alternative in managing patients with paraquat poisoning.

  5. Investigating global trends in paraquat intoxication research from 1962 to 2015 using bibliometric analysis.

    Science.gov (United States)

    Zyoud, Sa'ed H

    2018-06-01

    Paraquat is considered to be the main pesticide involved in accidental and intentional poisoning, and is responsible for a high rate of morbidity and mortality. The aim of this study is to present a comprehensive bibliometric analysis of paraquat intoxication-related research. Data was retrieved in March 2017 from the Scopus database. An overview of the research on paraquat intoxication was presented alongside the information related to several bibliometric indicators, such as research trends, countries with their h-index, collaboration, hot issues, top-cited publications, journals, and institutions. There were 1971 publications related to paraquat intoxication in the Scopus database that were published between 1966 and 2015. There was increasing research output in the field of paraquat intoxication during the period 2006-2015. The USA published the highest number of publications (n = 338), followed by Japan with 228 publications, and China with 159 publications. The USA and the UK achieved the greatest h-index values (h-index values of 49 and 31, respectively). The USA also achieved the highest number of publications involving international collaboration, with 55 publications, followed by the UK, with 18 publications. The most prevalent topics in this field were "acute paraquat intoxication," "toxic effects of paraquat to the lung," and "mechanism of paraquat toxicity." Although a substantial amount of research has been produced on paraquat intoxication for most developed countries, there are research gaps regarding the international research agenda in this research area. The findings could be applied for prioritizing and organizing future research efforts related to paraquat toxicity. © 2018 Wiley Periodicals, Inc.

  6. Using bosentan to treat paraquat poisoning-induced acute lung injury in rats.

    Directory of Open Access Journals (Sweden)

    Zhongchen Zhang

    Full Text Available BACKGROUND: Paraquat poisoning is well known for causing multiple organ function failure (MODS and high mortality. Acute lung injury and advanced pulmonary fibrosis are the most serious complications. Bosentan is a dual endothelin receptor antagonist. It plays an important role in treating PF. There is no related literature on the use of bosentan therapy for paraquat poisoning. OBJECTIVE: To study the use of bosentan to treat acute lung injury and pulmonary fibrosis as induced by paraquat. METHOD: A total of 120 adult Wister male rats were randomly assigned to three groups: the paraquat poisoning group (rats were intragastrically administered with paraquat at 50 mg/kg body weight once at the beginning; the bosentan therapy group (rats were administered bosentan at 100 mg/kg body weight by intragastric administration half an hour after paraquat was administered, then the same dose was administered once a day; and a control group (rats were administered intragastric physiological saline. On the 3rd, 7th, 14th, and 21st days following paraquat exposure, rats were sacrificed, and samples of lung tissue and venous blood were collected. The levels of transforming growth factor-β1 (TGF-β1, endothelin-1 (ET-1, and hydroxyproline (HYP in the plasma and lung homogenate were determined. Optical and electronic microscopes were used to examine pathological changes. RESULT: The TGF-β1, ET-1, and HYP of the paraquat poisoning group were significantly higher than in the control group, and they were significantly lower in the 21st day therapy group than in the paraquat poisoning group on the same day. Under the optical and electronic microscopes, lung tissue damage was observed to be more severe but was then reduced after bosentan was administered. CONCLUSION: Bosentan can reduce inflammation factor release. It has a therapeutic effect on acute lung injury as induced by paraquat.

  7. Impact of paraquat regulation on suicide in South Korea.

    Science.gov (United States)

    Cha, Eun Shil; Chang, Shu-Sen; Gunnell, David; Eddleston, Michael; Khang, Young-Ho; Lee, Won Jin

    2016-04-01

    Ingestion of pesticides (mainly paraquat) accounted for one-fifth of suicides in South Korea in 2006-10. We investigated the effect on suicide mortality of regulatory action, culminating in a ban on paraquat in South Korea in 2011-12. We calculated age-standardized method-specific suicide mortality rates among people aged ≥15 in South Korea (1983-2013) using registered death data. Negative binomial regression was used to estimate changes in the rate and number of pesticide suicides in 2013, compared with those expected based on previous trends (2003-11). Pesticide suicide mortality halved from 5.26 to 2.67 per 100 000 population between 2011 and 2013. Compared with the number expected based on previous trends, the regulations were followed by an estimated 847 [95% confidence interval (CI) -1180 to -533] fewer pesticide suicides, a 37% reduction in rates (rate ratio = 0.63, 95% CI 0.55 to 0.73) in 2013. The decline in pesticide suicides after the regulations was seen in all age/sex/geographical groups. The absolute reduction in the number of suicides was greatest among men, the elderly and in rural areas. The reduction in pesticide suicides contributed to 56% of the decline in overall suicides that occurred between 2011 and 2013. There was no impact of the regulations on crop yield. The regulation of paraquat in South Korea in 2011-12 was associated with a reduction in pesticide suicide. Further legislative interventions to prevent the easy availability of highly lethal suicide methods are recommended for reducing the number of suicides worldwide. © The Author 2015; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.

  8. Studies of the occupational exposure of Malaysian plantation workers to paraquat

    Energy Technology Data Exchange (ETDEWEB)

    Chester, G; Woollen, B H

    1982-02-01

    Studies carried out on the occupational exposure to paraquat of plantation workers in Malaysia comprised quantitative estimates of dermal and respiratory exposure of knapsack spray operators, carriers, and rubber tappers operating under their normal working conditions. Spray operators have been shown to be dermally exposed to paraquat by walking through recently sprayed vegetation and into their own spray, regular adjustment and unblocking of spray nozzles and leakage, and overfilling of knapsack spray tanks. Carriers also received measurable dermal exposure from walking through recently sprayed vegetation and accidental spillage when carrying and loading. The infrequent and negligible dermal exposure of tappers resulted from walking through recently sprayed vegetation. Determinations of the total airborne paraquat concentrations in the breathing zone show that spray operators and carriers are exposed to an order of 1% or less of the current TLV for respirable paraquat. No paraquat was detected in the breathing zones of tappers working in simultaneously sprayed blocks. The calculated ranges of dermal and respiratory exposures, when compared with published data on both the exposure to, and the toxicity of, paraquat, indicate that there should be no toxicological risk to any of the three groups studied as a result of using paraquat.

  9. Paraquat and psychological stressor interactions as pertains to Parkinsonian co-morbidity

    Directory of Open Access Journals (Sweden)

    Chris Rudyk

    2015-01-01

    Full Text Available A number of epidemiological and experimental studies have implicated the non-selective herbicide, paraquat, in the development of sporadic Parkinson's disease (PD. While preclinical research has focused mainly on elucidating the nigrostriatal effects of paraquat, relatively little data are available concerning non-motor brain systems and inflammatory immune processes (which have been implicated in PD. Hence, in the present study, we sought to take a multi-system approach to characterize the influence of paraquat upon extra-nigrostriatal brain regions, as well ascertain whether the impact of the pesticide might be enhanced in the context of chronic intermittent stressor exposure. Our findings support the contention that paraquat itself acted as a systemic stressor, with the pesticide increasing plasma corticosterone, as well as altering neurochemical activity in the locus coeruleus, paraventricular nucleus of the hypothalamus, nucleus accumbens, dorsal striatum, and central amygdala. However, with the important exception striatal dopamine turnover, the stressor treatment did not further augment these effects. Additionally, paraquat altered inter-cytokine correlations and, to a lesser extent, circulating cytokine levels, and concomitant stress exposure modulated some of these effects. Finally, paraquat provoked significant (albeit modest reductions of sucrose preference and weight gain, hinting at possible anhendonic-like or sickness responses. These data suggest that, in addition to being a well known oxidative stress generator, paraquat can act as a systemic stressor affecting hormonal and neurochemical activity, but largely not interacting with a concomitant stressor regimen.

  10. Paraquat Exposure of Pregnant Women and Neonates in Agricultural Areas in Thailand

    Directory of Open Access Journals (Sweden)

    Pajaree Konthonbut

    2018-06-01

    Full Text Available This study aimed to assess paraquat concentrations in the urine of women at 28 weeks of pregnancy, delivery and 2 months postpartum and in the meconium of neonates. In all, 79 pregnant women were recruited from three hospitals located in agricultural areas in Thailand. The subjects were interviewed about personal characteristics, agricultural activities and pesticide use patterns. Paraquat was analyzed in urine and meconium using high performance liquid chromatography equipped with a fluorescence detector. The geometric mean (GSD of urinary paraquat concentrations at 28 weeks of pregnancy, delivery and 2 months postpartum were 2.04 (4.22, 2.06 (5.04 and 2.42 (5.33 ng/mL, respectively. The urinary paraquat concentrations at 28 weeks of pregnancy, delivery and 2 months postpartum between agriculturist and non-agriculturist were not significantly different (p = 0.632, p = 0.915, p = 0.57 respectively. The geometric mean (GSD of paraquat concentration in the meconium was 33.31 (4.59 ng/g. The factors predicting paraquat exposures among pregnant women and neonates included working outside, living near farmland, having family members who work on a farm, drinking well water and using herbicides or paraquat.

  11. Effects of paraquat on Escherichia coli: Differences between B and K-12 strains

    International Nuclear Information System (INIS)

    Kitzler, J.W.; Minakami, H.; Fridovich, I.

    1990-01-01

    Escherichia coli B and K-12 are equally susceptible to the bacteriostatic effects of aerobic paraquat, but they differed strikingly when the lethality of paraquat was evaluated. E. coli B suffered an apparent loss of viability when briefly exposed to paraquat, whereas E. coli K-12 did not. This difference depended on the ability of the B-strain, but not the K-12 strain, to retain internalized paraquat; the B strain was killed on aerobic tryptic soy-yeast extract plates during the incubation which preceded the counting of colonies. This difference in retention of paraquat between strains was demonstrated by delayed loss of viability, by growth inhibition, and by cyanide-resistant respiration after brief exposure to paraquat, washing, and testing in fresh medium. This difference was also shown by using [ 14 C]paraquat. This previously unrecognized difference between E. coli B and K-12 has been the cause of apparently contradictory reports and should lead to some reevaluation of the pertinent literature

  12. Clinical features and prognosis of paraquat poisoning in French Guiana: A review of 62 cases.

    Science.gov (United States)

    Elenga, Narcisse; Merlin, Caroline; Le Guern, Rémi; Kom-Tchameni, Rémi; Ducrot, Yves-Marie; Pradier, Maxime; Ntab, Balthazar; Dinh-Van, Kim-Anh; Sobesky, Milko; Mathieu, Daniel; Dueymes, Jean-Marc; Egmann, Gérald; Kallel, Hatem; Mathieu-Nolf, Monique

    2018-04-01

    Paraquat is a nonselective contact herbicide of great toxicological importance, being associated with high mortality rates. Because of its high toxicity, the European Union withdrew it from its market in 2007. The aim of this study is to analyze all cases of paraquat poisoning hospitalized in French Guiana in order to assess their incidence and main characteristics.Medical records of all paraquat intoxicated patients hospitalized from 2008 until 2015 were reviewed in this retrospective study.Demographics, clinical presentation, and laboratory data were evaluated.A total of 62 cases were reviewed. The incidence of paraquat poisoning was 3.8/100,000 inhabitants/year. There were 44 adults and 18 children younger than 16 years of age. The median ages were 31 years [18.08-75.25] in adults and 13.4 years [0.75-15.08] in children, respectively. The median duration of hospitalization was longer in children [15.5 days (1-24)] than in adults [2 days (1-30)], P < .01. The majority of cases was due to self-poisoning (84%).Children had ingested a lower quantity of paraquat [48.8 mg/kg (10-571.1)] than adults [595.8 mg/kg (6-3636.4), P = .03]. There were more deaths among adults (65%) than in children (22%), P = .004. The severity and outcome was determined primarily by the amount of paraquat ingested.In conclusion, French Guiana has the largest cohort of paraquat poisonings in the European Union. The major factor affecting the prognosis of patients was the ingested amount of paraquat. The administration of activated charcoal or Pemba, in situ, within the first hour after ingestion of paraquat is essential.

  13. Increased oxidative stress and antioxidant expression in mouse keratinocytes following exposure to paraquat

    International Nuclear Information System (INIS)

    Black, Adrienne T.; Gray, Joshua P.; Shakarjian, Michael P.; Laskin, Debra L.; Heck, Diane E.; Laskin, Jeffrey D.

    2008-01-01

    Paraquat (1,1'-dimethyl-4,4'-bipyridinium) is a widely used herbicide known to induce skin toxicity. This is thought to be due to oxidative stress resulting from the generation of cytotoxic reactive oxygen intermediates (ROI) during paraquat redox cycling. The skin contains a diverse array of antioxidant enzymes which protect against oxidative stress including superoxide dismutase (SOD), catalase, glutathione peroxidase-1 (GPx-1), heme oxygenase-1 (HO-1), metallothionein-2 (MT-2), and glutathione-S-transferases (GST). In the present studies we compared paraquat redox cycling in primary cultures of undifferentiated and differentiated mouse keratinocytes and determined if this was associated with oxidative stress and altered expression of antioxidant enzymes. We found that paraquat readily undergoes redox cycling in both undifferentiated and differentiated keratinocytes, generating superoxide anion and hydrogen peroxide as well as increased protein oxidation which was greater in differentiated cells. Paraquat treatment also resulted in increased expression of HO-1, Cu,Zn-SOD, catalase, GSTP1, GSTA3 and GSTA4. However, no major differences in expression of these enzymes were evident between undifferentiated and differentiated cells. In contrast, expression of GSTA1-2 was significantly greater in differentiated relative to undifferentiated cells after paraquat treatment. No changes in expression of MT-2, Mn-SOD, GPx-1, GSTM1 or the microsomal GST's mGST1, mGST2 and mGST3, were observed in response to paraquat. These data demonstrate that paraquat induces oxidative stress in keratinocytes leading to increased expression of antioxidant genes. These intracellular proteins may be important in protecting the skin from paraquat-mediated cytotoxicity

  14. A Rice CPYC-Type Glutaredoxin OsGRX20 in Protection against Bacterial Blight, Methyl Viologen and Salt Stresses

    Directory of Open Access Journals (Sweden)

    Xi Ning

    2018-02-01

    Full Text Available Glutaredoxins (GRXs belong to the antioxidants involved in the cellular stress responses. In spite of the identification 48 GRX genes in rice genomes, the biological functions of most of them remain unknown. Especially, the biological roles of members of GRX family in disease resistance are still lacking. Our proteomic analysis found that OsGRX20 increased by 2.7-fold after infection by bacterial blight. In this study, we isolated and characterized the full-length nucleotide sequences of the rice OsGRX20 gene, which encodes a GRX family protein with CPFC active site of CPYC-type class. OsGRX20 protein was localized in nucleus and cytosol, and its transcripts were expressed predominantly in leaves. Several stress- and hormone-related motifs putatively acting as regulatory elements were found in the OsGRX20 promoter. Real-time quantitative PCR analysis indicated that OsGRX20 was expressed at a significantly higher level in leaves of a resistant or tolerant rice genotype, Yongjing 50A, than in a sensitive genotype, Xiushui 11, exposed to bacterial blight, methyl viologen, heat, and cold. Its expression could be induced by salt, PEG-6000, 2,4-D, salicylic acid, jasmonic acid, and abscisic acid treatments in Yongjing 50A. Overexpression of OsGRX20 in rice Xiushui 11 significantly enhanced its resistance to bacterial blight attack, and tolerance to methyl viologen and salt stresses. In contrast, interference of OsGRX20 in Yongjing 50A led to increased susceptibility to bacterial blight, methyl viologen and salt stresses. OsGRX20 restrained accumulation of superoxide radicals in aerial tissue during methyl viologen treatment. Consistently, alterations in OsGRX20 expression affect the ascorbate/dehydroascorbate ratio and the abundance of transcripts encoding four reactive oxygen species scavenging enzymes after methyl viologen-induced stress. Our results demonstrate that OsGRX20 functioned as a positive regulator in rice tolerance to multiple stresses

  15. Magnetic Field Effects on Photoelectrochemical Reactions of Porphyrin-Viologen Linked Compounds in an Ionic Liquid

    Science.gov (United States)

    Tahara, Hironobu; Yonemura, Hiroaki; Harada, Satoko; Yamada, Sunao

    2011-08-01

    Magnetic field effects (MFEs) on photoelectrochemical reactions of three porphyrin-viologen linked compounds with various methylene groups [ZnP(n)V (n=4,6,8)] were examined in 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) as an ionic liquid using a two-electrode cell. Stable anodic photocurrents are produced by irradiating ZnP(n)V (n=4,6,8) in [BMIM][BF4] with visible light, and the MFEs on photocurrents were clearly observed in ZnP(n)V (n=4,6,8). The MFEs on photocurrents increase with magnetic field for lower magnetic fields (B ≤200 mT) and are constant for higher magnetic fields (B > 200 mT). The magnitude of the MFEs in ZnP(n)V (n=6,8) are larger than that in ZnP(4)V. The MFEs can be explained by radical pair mechanism. The magnitude of the MFEs is larger than those in electrodes modified with ZnP(n)V (n=4,6,8) as Langmuir-Blodgett films. The results are most likely attributable to the properties of [BMIM][BF4] and the mechanism of photoelectrochemical reaction.

  16. Effects of Exogenous Melatonin on Methyl Viologen-Mediated Oxidative Stress in Apple Leaf

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    Zhiwei Wei

    2018-01-01

    Full Text Available Oxidative stress is a major source of damage of plants exposed to adverse environments. We examined the effect of exogenous melatonin (MT in limiting of oxidative stress caused by methyl viologen (MV; paraquatin in apple leaves (Malus domestica Borkh.. When detached leaves were pre-treated with melatonin, their level of stress tolerance increased. Under MV treatment, melatonin effectively alleviated the decrease in chlorophyll concentrations and maximum potential Photosystem II efficiency while also mitigating membrane damage and lipid peroxidation when compared with control leaves that were sprayed only with water prior to the stress experiment. The melatonin-treated leaves also showed higher activities and transcripts of antioxidant enzymes superoxide dismutase, peroxidase, and catalase. In addition, the expression of genes for those enzymes was upregulated. Melatonin-synthesis genes MdTDC1, MdT5H4, MdAANAT2, and MdASMT1 were also upregulated under oxidative stress in leaves but that expression was suppressed in response to 1 mM melatonin pretreatment during the MV treatments. Therefore, we conclude that exogenous melatonin mitigates the detrimental effects of oxidative stress, perhaps by slowing the decline in chlorophyll concentrations, moderating membrane damage and lipid peroxidation, increasing the activities of antioxidant enzymes, and changing the expression of genes for melatonin synthesis.

  17. Promising Low-Toxicity of Viologen-Phosphorus Dendrimers against Embryonic Mouse Hippocampal Cells

    Directory of Open Access Journals (Sweden)

    Jean-Pierre Majoral

    2013-09-01

    Full Text Available A new class of viologen-phosphorus dendrimers (VPDs has been recently shown to possess the ability to inhibit neurodegenerative processes in vitro. Nevertheless, in the Central Nervous Systems domain, there is little information on their impact on cell functions, especially on neuronal cells. In this work, we examined the influence of two VPD (VPD1 and VPD3 of zero generation (G0 on murine hippocampal cell line (named mHippoE-18. Extended analyses of cell responses to these nanomolecules comprised cytotoxicity test, reactive oxygen species (ROS generation studies, mitochondrial membrane potential (ΔΨm assay, cell death detection, cell morphology assessment, cell cycle studies, as well as measurements of catalase (CAT activity and glutathione (GSH level. The results indicate that VPD1 is more toxic than VPD3. However, these two tested dendrimers did not cause a strong cellular response, and induced a low level of apoptosis. Interestingly, VPD1 and VPD3 treatment led to a small decline in ROS level compared to untreated cells, which correlated with slightly increased catalase activity. This result indicates that the VPDs can indirectly lower the level of ROS in cells. Summarising, low-cytotoxicity on mHippoE-18 cells together with their ability to quench ROS, make the VPDs very promising nanodevices for future applications in the biomedical field as nanocarriers and/or drugs per se.

  18. Photoinduced electron transfer between anionic fluorophores and methyl viologen in homogeneous and microheterogeneous media

    Energy Technology Data Exchange (ETDEWEB)

    Burai, Tarak Nath; Panda, Debashis; Iyer, E Siva Subramaniam [Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076 (India); Datta, Anindya, E-mail: anindya@chem.iitb.ac.in [Department of Chemistry, Indian Institute of Technology Bombay, Powai, Mumbai 400 076 (India)

    2012-11-15

    The rate and extent of photoinduced electron transfer change significantly as a result of confinement in nanovolumes. Study of such processes is an active area of research in physical chemistry. The effect is most interesting when the molecules that participate in PET are charged. In the present article, the modulation of PET has been studied for two anionic fluorophores: Lucifer Yellow CH and chlorin p{sub 6} with Methylviologen dication. PET, manifested in the quenching of fluorescence of the fluorophores, has been modulated by incorporating the molecules in organized assemblies like micelles, reverse micelles and supramolecular hosts. The dynamics of the process has been monitored in the femtosecond to nanosecond timescale. The modulation of the electron transfer has been found to be occurring mainly due to the disruption of contact ion pairs formed between the fluorophores and the quencher. - Highlights: Black-Right-Pointing-Pointer Modulation of PET of biologically active fluorophores and Methyl viologen. Black-Right-Pointing-Pointer Static and Dynamic Quenching present. Black-Right-Pointing-Pointer PET enhanced upon encapsulation, studied through Fluorescence upconversion experiments. Black-Right-Pointing-Pointer Rotational anisotropy has significant contribution in quenching.

  19. Photoinduced electron transfer between anionic fluorophores and methyl viologen in homogeneous and microheterogeneous media

    International Nuclear Information System (INIS)

    Burai, Tarak Nath; Panda, Debashis; Iyer, E Siva Subramaniam; Datta, Anindya

    2012-01-01

    The rate and extent of photoinduced electron transfer change significantly as a result of confinement in nanovolumes. Study of such processes is an active area of research in physical chemistry. The effect is most interesting when the molecules that participate in PET are charged. In the present article, the modulation of PET has been studied for two anionic fluorophores: Lucifer Yellow CH and chlorin p 6 with Methylviologen dication. PET, manifested in the quenching of fluorescence of the fluorophores, has been modulated by incorporating the molecules in organized assemblies like micelles, reverse micelles and supramolecular hosts. The dynamics of the process has been monitored in the femtosecond to nanosecond timescale. The modulation of the electron transfer has been found to be occurring mainly due to the disruption of contact ion pairs formed between the fluorophores and the quencher. - Highlights: ► Modulation of PET of biologically active fluorophores and Methyl viologen. ► Static and Dynamic Quenching present. ► PET enhanced upon encapsulation, studied through Fluorescence upconversion experiments. ► Rotational anisotropy has significant contribution in quenching.

  20. Clinical screening of paraquat in plasma samples using capillary electrophoresis with contactless conductivity detection: Towards rapid diagnosis and therapeutic treatment of acute paraquat poisoning in Vietnam.

    Science.gov (United States)

    Vu, Anh Phuong; Nguyen, Thi Ngan; Do, Thi Trang; Doan, Thu Ha; Ha, Tran Hung; Ta, Thi Thao; Nguyen, Hung Long; Hauser, Peter C; Nguyen, Thi Anh Huong; Mai, Thanh Duc

    2017-08-15

    The employment of a purpose-made capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (C 4 D) as a simple and cost-effective solution for clinical screening of paraquat in plasma samples for early-stage diagnosis of acute herbicide poisoning is reported. Paraquat was determined using an electrolyte composed of 10mM histidine adjusted to pH 4 with acetic acid. A detection limit of 0.5mg/L was achieved. Good agreement between results from CE-C 4 D and the confirmation method (HPLC-UV) was obtained, with relative errors for the two pairs of data better than 20% for 31 samples taken from paraquat-intoxicated patients. The results were used by medical doctors for identification and prognosis of acute paraquat poisoning cases. The objective of the work is the deployment of the developed approach in rural areas in Vietnam as a low-cost solution to reduce the mortality rate due to accidental or suicidal ingestion of paraquat. Copyright © 2017. Published by Elsevier B.V.

  1. A simple high performance liquid chromatography method for analyzing paraquat in soil solution samples.

    Science.gov (United States)

    Ouyang, Ying; Mansell, Robert S; Nkedi-Kizza, Peter

    2004-01-01

    A high performance liquid chromatography (HPLC) method with UV detection was developed to analyze paraquat (1,1'-dimethyl-4,4'-dipyridinium dichloride) herbicide content in soil solution samples. The analytical method was compared with the liquid scintillation counting (LSC) method using 14C-paraquat. Agreement obtained between the two methods was reasonable. However, the detection limit for paraquat analysis was 0.5 mg L(-1) by the HPLC method and 0.05 mg L(-1) by the LSC method. The LSC method was, therefore, 10 times more precise than the HPLC method for solution concentrations less than 1 mg L(-1). In spite of the high detection limit, the UC (nonradioactive) HPLC method provides an inexpensive and environmentally safe means for determining paraquat concentration in soil solution compared with the 14C-LSC method.

  2. Paraquat induces oxidative stress and neuronal cell death; neuroprotection by water-soluble Coenzyme Q10

    International Nuclear Information System (INIS)

    McCarthy, S.; Somayajulu, M.; Sikorska, M.; Borowy-Borowski, H.; Pandey, S.

    2004-01-01

    Neuronal cell death induced by oxidative stress is correlated with numerous neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and stroke. The causes of sporadic forms of age-related neurodegenerative diseases are still unknown. Recently, a correlation between paraquat exposure and neurodegenerative diseases has been observed. Paraquat, a nonselective herbicide, was once widely used in North America and is still routinely used in Taiwan. We have used differentiated Human Neuroblastoma (SHSY-5Y) cells as an in vitro model to study the mechanism of cell death induced by paraquat. We observed that paraquat-induced oxidative stress in differentiated SHSY-5Y cells as indicated by an increase in the production of cellular reactive oxygen species (ROS). Furthermore, apoptosis was evident as indicated by cellular and nuclear morphology and DNA fragmentation. Interestingly, pretreatment of SHSY-5Y cells with water-soluble Coenzyme Q 10 (CoQ 10 ) before paraquat exposure inhibited ROS generation. Pretreatment with CoQ 10 also significantly reduced the number of apoptotic cells and DNA fragmentation. We also analyzed the effect of paraquat and CoQ 10 on isolated mitochondria. Our results indicated that treatment with paraquat induced the generation of ROS from isolated mitochondria and depolarization of the inner mitochondrial membrane. Pretreatment with CoQ 10 was able to inhibit ROS generation from isolated mitochondria as well as the collapse of mitochondrial membrane potential. Our results indicate that water-soluble CoQ 10 can prevent oxidative stress and neuronal damage induced by paraquat and therefore, can be used for the prevention and therapy of neurodegenerative diseases caused by environmental toxins

  3. Paraquat-poisoning in the rabbit lungs: high resolution computed tomographic findings and pathologic correlation

    International Nuclear Information System (INIS)

    Lee, Kyung Soo; Kim, Eui Han; Lee, Byoung Ho; Kim, Kun Sang

    1992-01-01

    The authors evaluated high resolution computed tomographic (HRCT) findings of the isolated rabbit lungs with paraquat poisoning, and the findings were correlated with pathologic specimens. The purposes of this study are 1) to obtain the HRCT findings of the normal rabbit lung. 2) to find out if pulmonary pathology can be induced in rabbits by paraquat, and 3) to correlate the HRCT findings to those of pathology. Thirty rabbits were divided into three groups: group I included four control rabbits; group II included 16 rabbits given paraquat intraperitoneally (IP group); and group III included 10 rabbits given paraquat intravenously (IV group). The rabbits were sacrificed seven, 10, and 14 days after injection of various amount of paraquat, and then the lungs were isolated for HRCT and pathologic studies. Gross and microscopic findings of the three groups of control and paraquat-injected rabbit lungs were correlated with HRCT findings. Pulmonary congestion, mild thickening of alveolar walls and septae, and multifocal micro-atelectasis were the man pathologic findings of the lungs in both groups of the rabbits. Pulmonary hemorrhage was noted in five (31%) of 16 rabbits of IP group and three (30%) of 10 IV group. Pulmonary edema was seen in one rabbits (6%) of IP and four (40%) of IV group. Typical pulmonary fibrosis was seen in one rabbit of IP (6%) and IV (10%) group, respectively. There was no correlation between the amount of paraquat and frequency of the pulmonary pathology. Pulmonary fibrosis was seen at least one week after the paraquat injection. On HRCT, pulmonary hemorrhage and edema appeared as diffuse air-space consolidation and pulmonary fibrosis as linear or band-like opacities. However, minimal changes such as mild congestion

  4. Paraquat prohibition and change in the suicide rate and methods in South Korea.

    Science.gov (United States)

    Myung, Woojae; Lee, Geung-Hee; Won, Hong-Hee; Fava, Maurizio; Mischoulon, David; Nyer, Maren; Kim, Doh Kwan; Heo, Jung-Yoon; Jeon, Hong Jin

    2015-01-01

    The annual suicide rate in South Korea is the highest among the developed countries. Paraquat is a highly lethal herbicide, commonly used in South Korea as a means for suicide. We have studied the effect of the 2011 paraquat prohibition on the national suicide rate and method of suicide in South Korea. We obtained the monthly suicide rate from 2005 to 2013 in South Korea. In our analyses, we adjusted for the effects of celebrity suicides, and economic, meteorological, and seasonal factors on suicide rate. We employed change point analysis to determine the effect of paraquat prohibition on suicide rate over time, and the results were verified by structural change analysis, an alternative statistical method. After the paraquat prohibition period in South Korea, there was a significant reduction in the total suicide rate and suicide rate by poisoning with herbicides or fungicides in all age groups and in both genders. The estimated suicide rates during this period decreased by 10.0% and 46.1% for total suicides and suicides by poisoning of herbicides or fungicides, respectively. In addition, method substitution effect of paraquat prohibition was found in suicide by poisoning by carbon monoxide, which did not exceed the reduction in the suicide rate of poisoning with herbicides or fungicides. In South Korea, paraquat prohibition led to a lower rate of suicide by paraquat poisoning, as well as a reduction in the overall suicide rate. Paraquat prohibition should be considered as a national suicide prevention strategy in developing and developed countries alongside careful observation for method substitution effects.

  5. Paraquat prohibition and change in the suicide rate and methods in South Korea.

    Directory of Open Access Journals (Sweden)

    Woojae Myung

    Full Text Available The annual suicide rate in South Korea is the highest among the developed countries. Paraquat is a highly lethal herbicide, commonly used in South Korea as a means for suicide. We have studied the effect of the 2011 paraquat prohibition on the national suicide rate and method of suicide in South Korea. We obtained the monthly suicide rate from 2005 to 2013 in South Korea. In our analyses, we adjusted for the effects of celebrity suicides, and economic, meteorological, and seasonal factors on suicide rate. We employed change point analysis to determine the effect of paraquat prohibition on suicide rate over time, and the results were verified by structural change analysis, an alternative statistical method. After the paraquat prohibition period in South Korea, there was a significant reduction in the total suicide rate and suicide rate by poisoning with herbicides or fungicides in all age groups and in both genders. The estimated suicide rates during this period decreased by 10.0% and 46.1% for total suicides and suicides by poisoning of herbicides or fungicides, respectively. In addition, method substitution effect of paraquat prohibition was found in suicide by poisoning by carbon monoxide, which did not exceed the reduction in the suicide rate of poisoning with herbicides or fungicides. In South Korea, paraquat prohibition led to a lower rate of suicide by paraquat poisoning, as well as a reduction in the overall suicide rate. Paraquat prohibition should be considered as a national suicide prevention strategy in developing and developed countries alongside careful observation for method substitution effects.

  6. Prediction of paraquat exposure and toxicity in clinically ill poisoned patients: a model based approach.

    Science.gov (United States)

    Wunnapuk, Klintean; Mohammed, Fahim; Gawarammana, Indika; Liu, Xin; Verbeeck, Roger K; Buckley, Nicholas A; Roberts, Michael S; Musuamba, Flora T

    2014-10-01

    Paraquat poisoning is a medical problem in many parts of Asia and the Pacific. The mortality rate is extremely high as there is no effective treatment. We analyzed data collected during an ongoing cohort study on self-poisoning and from a randomized controlled trial assessing the efficacy of immunosuppressive therapy in hospitalized paraquat-intoxicated patients. The aim of this analysis was to characterize the toxicokinetics and toxicodynamics of paraquat in this population. A non-linear mixed effects approach was used to perform a toxicokinetic/toxicodynamic population analysis in a cohort of 78 patients. The paraquat plasma concentrations were best fitted by a two compartment toxicokinetic structural model with first order absorption and first order elimination. Changes in renal function were used for the assessment of paraquat toxicodynamics. The estimates of toxicokinetic parameters for the apparent clearance, the apparent volume of distribution and elimination half-life were 1.17 l h(-1) , 2.4 l kg(-1) and 87 h, respectively. Renal function, namely creatinine clearance, was the most significant covariate to explain between patient variability in paraquat clearance.This model suggested that a reduction in paraquat clearance occurred within 24 to 48 h after poison ingestion, and afterwards the clearance was constant over time. The model estimated that a paraquat concentration of 429 μg l(-1) caused 50% of maximum renal toxicity. The immunosuppressive therapy tested during this study was associated with only 8% improvement of renal function. The developed models may be useful as prognostic tools to predict patient outcome based on patient characteristics on admission and to assess drug effectiveness during antidote drug development. © 2014 The British Pharmacological Society.

  7. Transcriptome profiling to discover putative genes associated with paraquat resistance in goosegrass (Eleusine indica L..

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    Jing An

    Full Text Available BACKGROUND: Goosegrass (Eleusine indica L., a serious annual weed in the world, has evolved resistance to several herbicides including paraquat, a non-selective herbicide. The mechanism of paraquat resistance in weeds is only partially understood. To further study the molecular mechanism underlying paraquat resistance in goosegrass, we performed transcriptome analysis of susceptible and resistant biotypes of goosegrass with or without paraquat treatment. RESULTS: The RNA-seq libraries generated 194,716,560 valid reads with an average length of 91.29 bp. De novo assembly analysis produced 158,461 transcripts with an average length of 1153.74 bp and 100,742 unigenes with an average length of 712.79 bp. Among these, 25,926 unigenes were assigned to 65 GO terms that contained three main categories. A total of 13,809 unigenes with 1,208 enzyme commission numbers were assigned to 314 predicted KEGG metabolic pathways, and 12,719 unigenes were categorized into 25 KOG classifications. Furthermore, our results revealed that 53 genes related to reactive oxygen species scavenging, 10 genes related to polyamines and 18 genes related to transport were differentially expressed in paraquat treatment experiments. The genes related to polyamines and transport are likely potential candidate genes that could be further investigated to confirm their roles in paraquat resistance of goosegrass. CONCLUSION: This is the first large-scale transcriptome sequencing of E. indica using the Illumina platform. Potential genes involved in paraquat resistance were identified from the assembled sequences. The transcriptome data may serve as a reference for further analysis of gene expression and functional genomics studies, and will facilitate the study of paraquat resistance at the molecular level in goosegrass.

  8. Transcriptome profiling to discover putative genes associated with paraquat resistance in goosegrass (Eleusine indica L.).

    Science.gov (United States)

    An, Jing; Shen, Xuefeng; Ma, Qibin; Yang, Cunyi; Liu, Simin; Chen, Yong

    2014-01-01

    Goosegrass (Eleusine indica L.), a serious annual weed in the world, has evolved resistance to several herbicides including paraquat, a non-selective herbicide. The mechanism of paraquat resistance in weeds is only partially understood. To further study the molecular mechanism underlying paraquat resistance in goosegrass, we performed transcriptome analysis of susceptible and resistant biotypes of goosegrass with or without paraquat treatment. The RNA-seq libraries generated 194,716,560 valid reads with an average length of 91.29 bp. De novo assembly analysis produced 158,461 transcripts with an average length of 1153.74 bp and 100,742 unigenes with an average length of 712.79 bp. Among these, 25,926 unigenes were assigned to 65 GO terms that contained three main categories. A total of 13,809 unigenes with 1,208 enzyme commission numbers were assigned to 314 predicted KEGG metabolic pathways, and 12,719 unigenes were categorized into 25 KOG classifications. Furthermore, our results revealed that 53 genes related to reactive oxygen species scavenging, 10 genes related to polyamines and 18 genes related to transport were differentially expressed in paraquat treatment experiments. The genes related to polyamines and transport are likely potential candidate genes that could be further investigated to confirm their roles in paraquat resistance of goosegrass. This is the first large-scale transcriptome sequencing of E. indica using the Illumina platform. Potential genes involved in paraquat resistance were identified from the assembled sequences. The transcriptome data may serve as a reference for further analysis of gene expression and functional genomics studies, and will facilitate the study of paraquat resistance at the molecular level in goosegrass.

  9. Paraquat intoxication and associated pathological findings in three dogs in South Africa

    Directory of Open Access Journals (Sweden)

    June H. Williams

    2016-11-01

    Full Text Available Paraquat is a bipyridylium non-selective contact herbicide commonly used worldwide. When ingestion occurs by humans and animals either accidentally, intentionally or maliciously, paraquat selectively accumulates in the lungs resulting in the production of oxygen-free radicals, causing membrane damage and cell death. Intoxicated subjects typically show progressive and fatal pulmonary haemorrhage, collapse and oedema. In individuals surviving the acute phase, pulmonary fibrosis develops. Gastrointestinal-, renal- and central nervous system clinical signs may also occur. Owing to the lack of effective treatment and absence of an antidote, the prognosis is poor. The clinical presentation, clinicopathological findings and treatment are briefly described of three dogs from one South African household, intoxicated with paraquat. Macroscopic and microscopic lesions in one dog that was necropsied, as well as pulmonary ultrastructure are detailed and illustrated for academic reference. All dogs presented with tachypnoea and dyspnoea 2–3 days after accidental paraquat ingestion. Treatment was aimed at reducing gastrointestinal absorption, enhancing elimination by diuresis and avoiding further oxidative damage by administration of antioxidants. All dogs, however, became progressively hypoxic despite treatment and were euthanised. Paraquat toxicity should be a differential diagnosis in dogs with unexplained progressive respiratory and gastrointestinal signs and renal failure. The local veterinary profession should be aware of accidental or intentional paraquat toxicity of animals. Existing literature, variations possible in canine clinical signs, measured parameters, lesions, as well as possible treatments, promising experimental antidotes and management options are discussed.

  10. A One-compartment direct glucose alkaline fuel cell with methyl viologen as electron mediator

    International Nuclear Information System (INIS)

    Liu, Xianhua; Hao, Miaoqing; Feng, Mengnan; Zhang, Lin; Zhao, Yong; Du, Xiwen; Wang, Guangyi

    2013-01-01

    Highlights: ► A glucose–air alkaline fuel cell without using noble metal catalysts has been developed. ► The rudimentary fuel cell generates a maximum power density of 0.62 mW m −2 . ► The high performance is attributed to the use of MV and nickel foam. ► Main oxidation products are small organic acids indicating deep oxidation of glucose. - Abstract: Glucose is abundant, renewable, non-toxic and convenient as a fuel for fuel cells, but current technologies are unavailable for us to directly oxidize it to obtain energy. Fuel cells using enzymes and micro-organisms as catalysts are limited by their extremely low power output and rather short durability. Fuel cells using precious metal catalyst are expensive for large-scale use. In this work, a one-compartment direct glucose alkaline fuel cell has been developed that use methyl viologen (MV) as electron mediator and nickel foam as the anode. The rudimentary fuel cell generates a maximum power density of 0.62 mW cm −2 , while the maximum current density is 5.03 mA cm −2 . Electro-catalytic activities of MV and the nickel foam in alkaline conditions were studied by cyclic voltammetry. It is indicated that the high performance of the fuel cell is attributed to the combined use of MV and nickel foam. 13 C-NMR and HPLC were used to analyze oxidation products of glucose. The result shows that the principal oxidation products are short-chain organic acids indicating deep oxidation of glucose is achieved

  11. Reaction of N,N’-dimethylformamide and divalent viologen molecule to generate an organic dopant for molybdenum disulfide

    Directory of Open Access Journals (Sweden)

    A. Fukui

    2018-05-01

    Full Text Available Tuning the carrier concentration is essential for semiconducting materials to apply optoelectronic devices. Molybdenum disulfide (MoS2 is a semiconducting material composed of atomically thin (∼0.7 nm thickness layers. To dope thin MoS2, instead of using conventional atom/ion injection processes, a surface charge transfer method was successfully applied. In this study, we report a simple preparation method of a molecular dopant applicable to the doping process. The method follows a previous report for producing a molecular dopant, benzyl viologen (BV which shows electron doping to MoS2. To prepare dopant BV molecules, a reduction process with a commercially available divalent BV by sodium borohydride (NaBH4 is required; however, the reaction requires a large consumption of NaBH4. NaBH4 drastically reacts with the solvent water itself. We found a reaction process of BV in an organic solvent, N,N’-dimethylformamide (DMF, by adding a small amount of water dissolving the divalent BV. The reaction is mild (at room temperature and is autonomous once DMF comes into contact with the divalent BV aqueous solution. The reaction can be monitored with a UV-Vis spectrometer, and kinetic analysis indicates two reaction steps between divalent/monovalent/neutral viologen isomers. The product was soluble in toluene and did not dissolve in water, indicating it is similar to the reported dopant BV. The synthesized molecule was found to act as a dopant for MoS2 by applying a metal-oxide-semiconductor field-effect-transistor (MOSFET structure. The process is a general method and applicable to other viologen-related dopants to tune the electronic structure of 2D materials to facilitate generating atomically thin devices.

  12. Reaction of N,N'-dimethylformamide and divalent viologen molecule to generate an organic dopant for molybdenum disulfide

    Science.gov (United States)

    Fukui, A.; Miura, K.; Ichimiya, H.; Tsurusaki, A.; Kariya, K.; Yoshimura, T.; Ashida, A.; Fujimura, N.; Kiriya, D.

    2018-05-01

    Tuning the carrier concentration is essential for semiconducting materials to apply optoelectronic devices. Molybdenum disulfide (MoS2) is a semiconducting material composed of atomically thin (˜0.7 nm thickness) layers. To dope thin MoS2, instead of using conventional atom/ion injection processes, a surface charge transfer method was successfully applied. In this study, we report a simple preparation method of a molecular dopant applicable to the doping process. The method follows a previous report for producing a molecular dopant, benzyl viologen (BV) which shows electron doping to MoS2. To prepare dopant BV molecules, a reduction process with a commercially available divalent BV by sodium borohydride (NaBH4) is required; however, the reaction requires a large consumption of NaBH4. NaBH4 drastically reacts with the solvent water itself. We found a reaction process of BV in an organic solvent, N,N'-dimethylformamide (DMF), by adding a small amount of water dissolving the divalent BV. The reaction is mild (at room temperature) and is autonomous once DMF comes into contact with the divalent BV aqueous solution. The reaction can be monitored with a UV-Vis spectrometer, and kinetic analysis indicates two reaction steps between divalent/monovalent/neutral viologen isomers. The product was soluble in toluene and did not dissolve in water, indicating it is similar to the reported dopant BV. The synthesized molecule was found to act as a dopant for MoS2 by applying a metal-oxide-semiconductor field-effect-transistor (MOSFET) structure. The process is a general method and applicable to other viologen-related dopants to tune the electronic structure of 2D materials to facilitate generating atomically thin devices.

  13. Clinical features and prognosis of paraquat poisoning: a review of 41 cases

    Science.gov (United States)

    Delirrad, Mohammad; Majidi, Mohammad; Boushehri, Behzad

    2015-01-01

    Purpose: Paraquat is a contact herbicide which is highly toxic to human. Deliberate self-poisoning with paraquat continues to be a major public health concern in many developing countries. This study aimed to evaluate the data on cases of acute paraquat poisoning and to compare different variables between survivors and non-survivors. Methods: In this cross sectional study, medical records of all paraquat intoxicated patients were reviewed at Taleghani hospital of Urmia, Iran, from 2007 to 2013, retrospectively. Demographics, clinical features and laboratory findings were evaluated. The variables compared between survivors and non-survivors were the amount of paraquat ingested, occurrence of vomiting after ingestion, time and place of hospital admission, length of hospital stay, leukocytosis, serum creatinine level and the outcomes. Results: A total of 41 patients were evaluated. The mean ± standard deviation of patients’ age were 31.6±16.9 years. The Length of hospital stay was 5.75±4.6 days. Most poisonings occurred in spring and summer. The in-hospital fatality rate was 46.3%. Statistically significant associations were found between the outcome of patients and the amount ingested (P=0.001), vomiting (P=0.004), early need to intensive cares (P=0.009), leukocytosis (P=0.001), serum creatinine levels (P=0.001), manifestations of acute hepatic (P<0.001) and respiratory failure (P=0.007). Conclusion: Ingestion of more than 30 ml, prompt vomiting, early need to intensive cares, leukocytosis, and multi-organ failures are major determinants for fatal outcome of paraquat poisoning. It may be useful to educate health professionals and the general population about the serious consequences of exposure to paraquat. PMID:26221379

  14. Temperature effect on the photoinduced reduction of methyl viologen with several sensitizers and the evolution of hydrogen from water

    Energy Technology Data Exchange (ETDEWEB)

    Nenadovic, M.T.; Micic, O.I.; Rajh, T.; Savic, D.

    1983-01-01

    Irradiation by visible light of an aqueous solution containing a photosensitizer, methyl viologen (MV/sup 2 +/) and ethylenediaminetetraacetic acid leads to the formation of the reduced form of methyl viologen (MV/sup +/). The quantum yield for the formation of MV/sup +/ depends strongly on the time during which the formation is observed owing to the reaction of MV/sup +/ with oxidative products and its reduction to MV/sup 0/. Proflavin, acridine yellow and ruthenium(II)tris(2,2-bipyridyl) were used as photosensitizers and showed the same ability to promote hydrogen evolution. When CdS was used as a sensitizer a factor of 10 less hydrogen was obtained than when the dyes were used. The redox catalysts platinum, Pt-TiO/sub 2/-RuO/sub 2/ and Pt-CdS in colloidal systems showed approximately the same activity towards the reduction of water. The reduction of MV/sup 2 +/ and the evolution of hydrogen were enhanced at higher temperatures (70/sup 0/C). The optimum conditions for water reduction on redox catalysts in colloidal system under continuous illumination are analysed.

  15. A π-Conjugation Extended Viologen as a Two-Electron Storage Anolyte for Total Organic Aqueous Redox Flow Batteries.

    Science.gov (United States)

    Luo, Jian; Hu, Bo; Debruler, Camden; Liu, Tianbiao Leo

    2018-01-02

    Extending the conjugation of viologen by a planar thiazolo[5,4-d]thiazole (TTz) framework and functionalizing the pyridinium with hydrophilic ammonium groups yielded a highly water-soluble π-conjugation extended viologen, 4,4'-(thiazolo[5,4-d]thiazole-2,5-diyl)bis(1-(3-(trimethylammonio)propyl)pyridin-1-ium) tetrachloride, [(NPr) 2 TTz]Cl 4  , as a novel two-electron storage anolyte for aqueous organic redox flow battery (AORFB) applications. Its physical and electrochemical properties were systematically investigated. Paired with 4-trimethylammonium-TEMPO (N Me -TEMPO) as catholyte, [(NPr) 2 TTz]Cl 4 enables a 1.44 V AORFB with a theoretical energy density of 53.7 Wh L -1 . A demonstrated [(NPr) 2 TTz]Cl 4 /N Me -TEMPO AORFB delivered an energy efficiency of 70 % and 99.97 % capacity retention per cycle. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. A study of ion exchange at the poly(butyl viologen)-electrolyte interface by SECM

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Chih-Yu.; Vasantha, V.S. [Department of Chemical Engineering, National Taiwan University, Taipei 10617 (China); Ho, Kuo-Chuan [Department of Chemical Engineering, National Taiwan University, Taipei 10617 (China); Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617 (China)

    2008-09-01

    In this work, the ion exchange characteristics of poly(butyl viologen) (PBV) thin films on a platinum electrode has been investigated by cyclic voltammetric (CV) scans. Since ferrocyanide anions (Fe(CN){sub 6}{sup 4-}) were added during the polymerization of the PBV thin-film for its stability, Fe(CN){sub 6}{sup 4-} could form charge transfer complex with monomer and co-deposited with polymer. Scanning electrochemical microscopy (SECM) was used to probe the released Fe(CN){sub 6}{sup 4-} ions from PBV film with Os(bpy){sub 3}Cl{sub 2} as a mediator for the approaching process in 0.5 M KCl medium. Mass changes during the redox process of the film were also monitored in-situ by electrochemical quartz crystal microbalance (EQCM). The ion exchange and transport behavior was observed during CV cycling of the film of the SECM and EQCM. The insertion and extraction of anions were found to be potential-dependence. Moreover, the decrease in tip current of released Fe(CN){sub 6}{sup 4-} with increasing cycle number accounted for the ion exchange between Fe(CN){sub 6}{sup 4-} and Cl{sup -} in the KCl electrolyte. However, the Fe(CN){sub 6}{sup 4-}/Fe(CN){sub 6}{sup 3-} redox couple was found to be highly stable between 0.0 and 0.5 V (vs. Ag/AgCl/saturated KCl) in the phosphate buffer solution. Therefore, the electrochemical property of Fe(CN){sub 6}{sup 4-}/Fe(CN){sub 6}{sup 3-} redox couple was studied at different scan rates using CV technique. The peak currents were directly proportional to the scan rate as predicted for a surface confined diffusionless system. The surface coverage ({gamma}) and the concentration of Fe(CN){sub 6}{sup 4-} were determined to be 1.88 x 10{sup -8} mol/cm{sup 2} and 0.641 mol/dm{sup 3}, respectively. By neglecting cations incorporation during redox reaction of the PBV film and also based on the results obtained from energy-dispersive X-ray spectroscopy for the films of as-deposited, reduced and oxidized states, an ion exchange mechanism was

  17. Atorvastatin protected from paraquat-induced cytotoxicity in alveolar macrophages via down-regulation of TLR-4

    NARCIS (Netherlands)

    Alizadeh-Tabrizi, Nazli; Malekinejad, Hassan; Varasteh, Soheil; Cheraghi, Hadi

    2017-01-01

    The current study designed to clarify the mechanism of paraquat-induced cytotoxicity and protective effects of Atorvastatin on freshly isolated alveolar macrophages (AMs). AMs were collected via bronchoalveolar lavage and exposed to various concentrations of paraquat in the presence and absence of

  18. An assessment of the role of redox cycling in mediating the toxicity of paraquat and nitrofurantoin

    Energy Technology Data Exchange (ETDEWEB)

    Adam, A.; Cohen, G.M. (Univ. of London (England)); Smith, L.L. (Imperial Chemical Industries plc, Cheshire (England))

    1990-04-01

    The abilities of paraquat, diquat, and nitrofurantoin to undergo cyclic oxidation and reduction with rat microsomal systems have been assessed and compared to that of the potent redox cycler, menadione. Diquat and menadione were found to be potent redox cyclers with comparable abilities to elicit a nonstoichiometric increase in both the consumption of O{sub 2} and the oxidation of NADPH, compared to the amounts of substrate added. In contrast, paraquat and nitrofurantoin redox cycled poorly, being an order of magnitude less potent than either diquat or menadione. This was reflected in kinetic studies using lung and liver microsomes. In order to assess redox cycling of the substrates in an intact lung system, the O{sub 2} consumption of rat lung slices was measured in the presence of all four compounds. A small increase in lung slice O{sub 2} uptake was observed with paraquat in the first 2.5 hr of incubation, possibly because of redox cycling of a high intracellular concentration of paraquat resulting from active accumulation into target cells. This stimulation in O{sub 2} uptake was no longer observed when slices were incubated for a longer period or with higher paraquat concentrations (10{sup {minus}4}M), possibly because of toxic effects in target cells. These results together with the poor ability to redox cycle with microsomes and the absence of a specific uptake system highlight the problem of associating redox cycling and oxidative stress in the mechanism of nitrofurantoin toxicity.

  19. Paraquat-loaded alginate/chitosan nanoparticles: Preparation, characterization and soil sorption studies

    Energy Technology Data Exchange (ETDEWEB)

    Santos Silva, Mariana dos; Sgarbi Cocenza, Daniela [Department of Environmental Engineering, Sao Paulo State University - UNESP, Avenida Tres de Marco, No. 511, CEP 18087-180, Sorocaba, SP (Brazil); Grillo, Renato; Silva de Melo, Nathalie Ferreira [Department of Environmental Engineering, Sao Paulo State University - UNESP, Avenida Tres de Marco, No. 511, CEP 18087-180, Sorocaba, SP (Brazil); Department of Biochemistry, Institute of Biology, State University of Campinas - UNICAMP, Campinas, SP (Brazil); Tonello, Paulo Sergio [Department of Environmental Engineering, Sao Paulo State University - UNESP, Avenida Tres de Marco, No. 511, CEP 18087-180, Sorocaba, SP (Brazil); Camargo de Oliveira, Luciana [Department of Chemistry, UFSCAr, Campus Sorocaba, SP (Brazil); Lopes Cassimiro, Douglas [Institute of Chemistry, Sao Paulo State University - UNESP, Araraquara, SP (Brazil); Rosa, Andre Henrique [Department of Environmental Engineering, Sao Paulo State University - UNESP, Avenida Tres de Marco, No. 511, CEP 18087-180, Sorocaba, SP (Brazil); Fernandes Fraceto, Leonardo, E-mail: leonardo@sorocaba.unesp.br [Department of Environmental Engineering, Sao Paulo State University - UNESP, Avenida Tres de Marco, No. 511, CEP 18087-180, Sorocaba, SP (Brazil); Department of Biochemistry, Institute of Biology, State University of Campinas - UNICAMP, Campinas, SP (Brazil)

    2011-06-15

    Agrochemicals are amongst the contaminants most widely encountered in surface and subterranean hydrological systems. They comprise a variety of molecules, with properties that confer differing degrees of persistence and mobility in the environment, as well as different toxic, carcinogenic, mutagenic and teratogenic potentials, which can affect non-target organisms including man. In this work, alginate/chitosan nanoparticles were prepared as a carrier system for the herbicide paraquat. The preparation and physico-chemical characterization of the nanoparticles was followed by evaluation of zeta potential, pH, size and polydispersion. The techniques employed included transmission electron microscopy, differential scanning calorimetry and Fourier transform infrared spectroscopy. The formulation presented a size distribution of 635 {+-} 12 nm, polydispersion of 0.518, zeta potential of -22.8 {+-} 2.3 mV and association efficiency of 74.2%. There were significant differences between the release profiles of free paraquat and the herbicide associated with the alginate/chitosan nanoparticles. Tests showed that soil sorption of paraquat, either free or associated with the nanoparticles, was dependent on the quantity of organic matter present. The results presented in this work show that association of paraquat with alginate/chitosan nanoparticles alters the release profile of the herbicide, as well as its interaction with the soil, indicating that this system could be an effective means of reducing negative impacts caused by paraquat.

  20. Paraquat poisoning: an experimental model of dose-dependent acute lung injury due to surfactant dysfunction

    Directory of Open Access Journals (Sweden)

    M.F.R. Silva

    1998-03-01

    Full Text Available Since the most characteristic feature of paraquat poisoning is lung damage, a prospective controlled study was performed on excised rat lungs in order to estimate the intensity of lesion after different doses. Twenty-five male, 2-3-month-old non-SPF Wistar rats, divided into 5 groups, received paraquat dichloride in a single intraperitoneal injection (0, 1, 5, 25, or 50 mg/kg body weight 24 h before the experiment. Static pressure-volume (PV curves were performed in air- and saline-filled lungs; an estimator of surface tension and tissue works was computed by integrating the area of both curves and reported as work/ml of volume displacement. Paraquat induced a dose-dependent increase of inspiratory surface tension work that reached a significant two-fold order of magnitude for 25 and 50 mg/kg body weight (P<0.05, ANOVA, sparing lung tissue. This kind of lesion was probably due to functional abnormalities of the surfactant system, as was shown by the increase in the hysteresis of the paraquat groups at the highest doses. Hence, paraquat poisoning provides a suitable model of acute lung injury with alveolar instability that can be easily used in experimental protocols of mechanical ventilation

  1. Experimental study of sucralfate intervention for paraquat poisoning in rats.

    Science.gov (United States)

    Junbo, Zhu; Yongtao, Yu; Hongbo, Li; Fenshuang, Zheng; Ruyun, Lin; Chun'ai, Yang

    2017-07-01

    This study explored the effects of sucralfate intervention as a novel treatment for paraquat (PQ) poisoning in Sprague-Dawley (SD) rats. After PQ poisoning, the SD rats were randomly divided into the PQ control group (treated with normal saline), the sodium bicarbonate (SB) treatment group, and the sucralfate (LTL) treatment group. Then, the rats were administered normal saline, sodium bicarbonate solution, or sucralfate suspension as an intervention by gastric lavage. At 1, 3, 6, and 10days after poisoning, the left lungs of some rats were removed to determine the lung wet/dry (W/D) weight ratio. Additionally, the serum cytokine levels were measured, and the lung and kidney tissues were pathologically examined. After treatment, the signs and symptoms of the rats were improved, the mortality rate was reduced, the W/D weight ratio of the lung was lower, the cytokine levels [transforming growth factor (TGF)-β1, interleukin (IL)-10, and tumor necrosis factor (TNF)-α] were decreased, and the pathological injuries of the lungs and kidneys were improved. Moreover, sucralfate was significantly more effective than the control (normal saline) group and the SB treatment group. The results showed that early gastrointestinal lavage with sucralfate effectively reduced the inflammatory response and lung and kidney injuries and improved the survival of the SD rats. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. [Intensive hemoperfusion and long-term hemofiltration for treatment of paraquat poisoning: a case report].

    Science.gov (United States)

    Peng, Zhi-Yun; Chang, Ping; Wang, Hua; Cen, Zhong-Ran; Zhou, Jian; Liu, Zhan-Guo

    2015-10-01

    A 20-year-old male patient was admitted in our department 14 h after paraquat poisoning at the dose of about 50 mL. The patient underwent intensive hemoperfusion for 2 h (3 times a day) for 9 consecutive days and received continuous renal replacement therapy (CRRT) in the mode of continuous veno-venous hemofiltration (CVVH) for 10 consecutive days in addition to routine medications. The biochemical indexes were monitored during the therapy. After the treatment, paraquat concentrations in the blood and urine were decreased, and the patient's urine volume (UV) increased, serum creatinine (Cr) level decreased, and the oxygenation index became normal. Dynamic CT scan showed no obvious pulmonary fibrosis. The patient was followed up for 6 months after discharge and no complaint of discomforts was reported. This case suggests that early intensive hemoperfusion and long-term CVVH may help improve the prognosis after paraquat poisoning.

  3. Intoxicación por paraquat: descripción de un caso clínico Paraquat poisoning: a case report

    Directory of Open Access Journals (Sweden)

    Julieth Hernández

    2008-07-01

    Full Text Available El paraquat es el herbicida más vendido en todo el mundo. Se absorbe por las vías digestiva e inhalatoria. Si llega a los pulmones, produce congestión, edema alveolar con aumento de macrófagos que progresa a fibrosis y edema pulmonar, los cuales se presentan hasta 14 días después de la exposición si el afectado no recibió tratamiento oportuno y correcto. El paraquat se dirige fundamentalmente a los pulmones y genera allí radicales libres oxidantes; por eso, en los casos de intoxicación aguda está totalmente contraindicado usar oxígeno excepto cuando la presión parcial de oxigeno en sangre arterial sea inferior a 50 mmHg. Se presenta un caso clínico de un paciente quien desarrolló un síndrome de distress respiratorio del adulto (SDRA secundario a ingesta intencional de paraquat. El manejo inicial se realizó con lavado gástrico y tierra de Fuller en solución acuosa al 30%. Posteriormente, el paciente desarrolló compromiso pulmonar y renal, los cuales fueron manejados con pulso de ciclofosfamida a 15 mg/kg/día por 2 días, metilprednisolona 1g/día por 3 días y posteriormente dexametasona 5 mg IV cada 6 horas por 5 días con una evolución clínica satisfactoria.Paraquat is the best-selling herbicide throughout the world, It is absorbed by the digestive and inhalatory routes. If it reaches the lungs, congestion with swelling is developed, increased alveolar macrophages that progresses to fibrosis and pulmonary edema, which occur until 14 days after exposure if not treated timely and correct. Paraquat is directed primarily to the lungs and therefore generates free radicals oxidants, which is why, in cases of acute poisoning is absolutely forbidden to use oxygen except where arterial blood partial pressure of oxygen in is less than 50 mm Hg. A patient who developed an adult respiratory distress syndrome (ARDS secondary to deliberate ingestion of paraquat is presented. Initial patient management was performed with gastric lavage

  4. HFE Genotype Restricts the Response to Paraquat in a Mouse Model of Neurotoxicity.

    Science.gov (United States)

    Nixon, Anne M; Meadowcroft, Mark D; Neely, Elizabeth B; Snyder, Amanda M; Purnell, Carson J; Wright, Justin; Lamendella, Regina; Nandar, Wint; Huang, Xuemei; Connor, James R

    2018-05-01

    Parkinson's disease is marked clinically by motor dysfunction and pathologically by dopaminergic cell loss in the substantia nigra and iron accumulation in the substantia nigra. The driver underlying iron accumulation remains unknown and could be genetic or environmental. The HFE protein is critical for the regulation of cellular iron uptake. Mutations within this protein are associated with increased iron accumulation including in the brain. We have focused on the commonly occurring H63D variant of the HFE gene as a disease modifier in a number of neurodegenerative diseases. To investigate the role of H63D HFE genotype, we generated a mouse model in which the wild-type (WT) HFE gene is replaced by the H67D gene variant (mouse homolog of the human H63D gene variant). Using paraquat toxicity as the model for Parkinson's disease, we found that WT mice responded as expected with significantly greater motor function, loss of tyrosine hydroxylase staining and increase microglial staining in the substantia nigra, and an increase in R 2 relaxation rate within the substantia nigra of the paraquat-treated mice compared to their saline-treated counterparts. In contrast, the H67D mice showed a remarkable resistance to paraquat treatment; specifically differing from the WT mice with no changes in motor function or changes in R 2 relaxation rates following paraquat exposure. At baseline, there were differences between the H67D HFE mice and WT mice in gut microbiome profile and increased L-ferritin staining in the substantia nigra that could account for the resistance to paraquat. Of particular note, the H67D HFE mice regardless of whether or not they were treated with paraquat had significantly less tyrosine hydroxylase immunostaining than WT. Our results clearly demonstrate that the HFE genotype impacts the expression of tyrosine hydroxylase in the substantia nigra, the gut microbiome and the response to paraquat providing additional support that the HFE genotype is a disease

  5. Enhanced photocurrent in RuL2(NCS)2/di-(3-aminopropyl)-viologen/SnO2/ITO system

    International Nuclear Information System (INIS)

    Lee, Wonjoo; Kwak, Chang Gon; Mane, R.S.; Min, Sun Ki; Cai, Gangri; Ganesh, T.; Koo, Gumae; Chang, Jinho; Cho, Byung Won; Kim, Sei-Ki; Han, Sung-Hwan

    2008-01-01

    A Ru(2,2'-bipyridine-4,4'-dicarboxylic acid) 2 (NCS) 2 [RuL 2 (NCS) 2 ]/di-(3-aminopropyl)-viologen (DAPV)/tin oxide (SnO 2 ) system was prepared and applied to extensive photocurrent generation with its maximum surface area. The SnO 2 thin films on tin-doped indium oxide (ITO) were prepared using the chemical bath deposition method. Then, RuL 2 (NCS) 2 /DAPV on SnO 2 /ITO was easily prepared using self-assembled monolayers (SAMs). The photocurrent measurement of the system showed an excellent photocurrent of 20 nA cm -2 under the air mass 1.5 conditions (100 mW cm -2 ), which was increased by a factor of four compared to ones without SnO 2 layers

  6. Compensatory role of the Nrf2–ARE pathway against paraquat toxicity: Relevance of 26S proteasome activity

    Directory of Open Access Journals (Sweden)

    Yasuhiko Izumi

    2015-11-01

    Full Text Available Oxidative stress and the ubiquitin–proteasome system play a key role in the pathogenesis of Parkinson disease. Although the herbicide paraquat is an environmental factor that is involved in the etiology of Parkinson disease, the role of 26S proteasome in paraquat toxicity remains to be determined. Using PC12 cells overexpressing a fluorescent protein fused to the proteasome degradation signal, we report here that paraquat yielded an inhibitory effect on 26S proteasome activity without an obvious decline in 20S proteasome activity. Relative low concentrations of proteasome inhibitors caused the accumulation of nuclear factor erythroid 2-related factor 2 (Nrf2, which is targeted to the ubiquitin–proteasome system, and activated the antioxidant response element (ARE-dependent transcription. Paraquat also upregulated the protein level of Nrf2 without increased expression of Nrf2 mRNA, and activated the Nrf2–ARE pathway. Consequently, paraquat induced expression of Nrf2-dependent ARE-driven genes, such as γ-glutamylcysteine synthetase, catalase, and hemeoxygenase-1. Knockdown of Nrf2 or inhibition of γ-glutamylcysteine synthetase and catalase exacerbated paraquat-induced toxicity, whereas suppression of hemeoxygenase-1 did not. These data indicate that the compensatory activation of the Nrf2–ARE pathway via inhibition of 26S proteasome serves as part of a cellular defense mechanism to protect against paraquat toxicity.

  7. Multiwall carbon nanotubes modulate paraquat toxicity in Arabidopsis thaliana.

    Science.gov (United States)

    Fan, Xiaoji; Xu, Jiahui; Lavoie, Michel; Peijnenburg, W J G M; Zhu, Youchao; Lu, Tao; Fu, Zhengwei; Zhu, Tingheng; Qian, Haifeng

    2018-02-01

    Carbon nanotubes can be either toxic or beneficial to plant growth and can also modulate toxicity of organic contaminants through surface sorption. The complex interacting toxic effects of carbon nanotubes and organic contaminants in plants have received little attention in the literature to date. In this study, the toxicity of multiwall carbon nanotubes (MWCNT, 50 mg/L) and paraquat (MV, 0.82 mg/L), separately or in combination, were evaluated at the physiological and the proteomic level in Arabidopsis thaliana for 7-14 days. The results revealed that the exposure to MWCNT had no inhibitory effect on the growth of shoots and leaves. Rather, MWCNT stimulated the relative electron transport rate and the effective photochemical quantum yield of PSII value as compared to the control by around 12% and lateral root production up to nearly 4-fold as compared to the control. The protective effect of MWCNT on MV toxicity on the root surface area could be quantitatively explained by the extent of MV adsorption on MWCNT and was related to stimulation of photosynthesis, antioxidant protection and number and area of lateral roots which in turn helped nutrient assimilation. The influence of MWCNT and MV on photosynthesis and oxidative stress at the physiological level was consistent with the proteomics analysis, with various over-expressed photosynthesis-related proteins (by more than 2 folds) and various under-expressed oxidative stress related proteins (by about 2-3 folds). This study brings new insights into the interactive effects of two xenobiotics (MWCNT and MV) on the physiology of a model plant. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Reactivity of paraquat with sodium salicylate: Formation of stable complexes

    International Nuclear Information System (INIS)

    Dinis-Oliveira, Ricardo Jorge; Guedes de Pinho, Paula; Ferreira, Antonio Cesar Silva; Silva, Artur M.S.; Afonso, Carlos; Bastos, Maria de Lourdes; Remiao, Fernando; Duarte, Jose Alberto; Carvalho, Felix

    2008-01-01

    Sodium salicylate (NaSAL) has been shown to be a promising antidote for the treatment of paraquat (PQ) poisonings. The modulation of the pro-oxidant and pro-inflammatory pathways, as well as the anti-thrombogenic properties of NaSAL are probably essential features for the healing effects provided by this drug. Nevertheless, a possible direct chemical reactivity between PQ and NaSAL is also a putative pathway to be considered, this hypothesis being the ground of the present study. In accordance, it is shown, for the first time that PQ and NaSAL react immediately in aqueous medium and within 2-3 min in the solid state. Photographs and scanning electron photomicrographs indicated that a new chemical entity is formed when both compounds are mixed. This assumption was corroborated by the evaluation of the melting point, and through several analytical techniques, namely ultraviolet/visible spectroscopy, nuclear magnetic resonance spectroscopy, gas chromatography/mass spectrometry/mass spectrometry (GC/MS/MS), liquid chromatography/electrospray ionization/mass spectrometry/mass spectrometry (LC/ESI/MS/MS) and infrared spectroscopy, which revealed that stable charge-transfer complexes are formed when PQ is mixed with NaSAL. LC/ESI/MS/MS allowed obtaining the stoichiometry of the charge-transfer complexes. In order to increase resolution, single value decomposition, acting as a filter, showed that the charge-transfer complexes with m/z 483, 643 and 803 correspond to the pseudo-molecular ions, respectively 1:2, 1:3 and 1:4 (PQ:NaSAL). In conclusion, these results provided a new and important mechanism of action of NaSAL against the toxicity mediated by PQ

  9. Paraquat, but not maneb, induces synucleinopathy and tauopathy in striata of mice through inhibition of proteasomal and autophagic pathways.

    Directory of Open Access Journals (Sweden)

    Jonathan Wills

    Full Text Available SNCA and MAPT genes and environmental factors are important risk factors of Parkinson's disease [PD], the second-most common neurodegenerative disease. The agrichemicals maneb and paraquat selectively target dopaminergic neurons, leading to parkinsonism, through ill-defined mechanisms. In the current studies we have analyzed the ability of maneb and paraquat, separately and together, to induce synucleinopathy and tauopathy in wild type mice. Maneb was ineffective in increasing α-synuclein [α-Syn] or p-Tau levels. By contrast, paraquat treatment of mice resulted in robust accumulation of α-Syn and hyperphosphorylation of Tau in striata, through activation of p-GSK-3β, a major Tau kinase. Co-treatment with maneb did not enhance the effects of paraquat. Increased hyperacetylation of α-tubulin was observed in paraquat-treated mice, suggesting cytoskeleton remodeling. Paraquat, but not maneb, inhibited soluble proteasomal activity on a peptide substrate but this was not associated with a decreased expression of 26S proteasome subunits. Both paraquat and maneb treatments increased levels of the autophagy inhibitor, mammalian target of rapamycin, mTOR, suggesting impaired axonal autophagy, despite increases in certain autophagic proteins, such as beclin 1 and Agt12. Autophagic flux was also impaired, as ratios of LC3 II to LC3 I were reduced in treated animals. Increased mTOR was also observed in postmortem human PD striata, where there was a reduction in the LC3 II to LC3 I ratio. Heat shock proteins were either increased or unchanged upon paraquat-treatment suggesting that chaperone-mediated autophagy is not hampered by the agrichemicals. These studies provide novel insight into the mechanisms of action of these agrichemicals, which indicate that paraquat is much more toxic than maneb, via its inhibitory effects on proteasomes and autophagy, which lead to accumulation of α-Syn and p-Tau.

  10. Paraquat Induced Changes in Reserve Carbohydrates, Fatty Acids and Oleoresin Content of Young Slash Pines

    Science.gov (United States)

    Claud L. Brown; Terry R. Clason; Jerry L. Michael

    1976-01-01

    Paraquat was fed into the terminal leaders of five-year-old slash pine trees and collected at weekly intervals for 4 weeks.Cytological observations showed a decrease in starch levels and a corresponding increase in content of oleoresin. Quantitative analysis indicated a decrease in starch accompanying increases in fatty acids, monoterpenes, and resin acids.

  11. Degradation of Paraquat in Gramoxone Pesticide with Addition of ZnO

    Directory of Open Access Journals (Sweden)

    Febrina Arfi

    2017-11-01

    Full Text Available Paraquat is the most toxic herbicide, the main agricultural crops and plantations that use them are cloves, cocoa, oil palm, rubber, coffee, and pepper. Therefore, it is necessary to study to degrade paraquat compounds by photolysis method with using ZnO. Photolysis is a process of UV irradiation with a wavelength of 200-400 nm. In this study Photolysis method used UV light with λ = 365 nm. Degradation of paraquat compound was done with the influence of variation of time without the addition ZnO, the influence of ZnO additional variations, and the effect of combination between variations of time and optimization of ZnO addition. The result of the study shows that photolysis degradation product without the addition of ZnO for 120 minutes has been degraded by 12.56%. While the optimum addition of 0.1 grams ZnO increased the percentage of degradation which is about 57.64%. This is proved that the addition of ZnO with photolysis method can degrade more paraquat compounds.

  12. DNA damage in grasshopper Chorthippus brunneus (Orthoptera) hatchlings following paraquat exposure.

    Science.gov (United States)

    Augustyniak, M; Nocoń, Ł; Kędziorski, A; Łaszczyca, P; Sawczyn, T; Tarnawska, M; Zawisza-Raszka, A

    2015-04-01

    Comet assay was applied to study genotoxic damage induced by paraquat (PQ) in brain cells of Chorthippus brunneus (Insecta: Orthoptera) hatchlings. Percentage of the comet fluorescence in the tail (TDNA), length of the comet tail (TL) and Olive tail moment (OTM) were used for quantitative assessment of the DNA damage. Multiple regression analysis supplemented standard statistical elaboration of the results. Increasing PQ concentrations applied either directly to the brain cells suspension (10, 50, and 250 μM PQ final concentration--in vitro protocol) or indirectly (50, 250, and 1250 μM PQ final concentration--in vivo protocol) provoked significant increase of oxidative damage to DNA (higher median TDNA and OTM values). The damage increased with time of exposure (0, 5, 15, and 30 min) following in vitro application, but decreased in longer interval (3 vs 24 h) after in vivo administration of paraquat. On contrary, median TL values did not correlate with paraquat concentration irrespectively of the exposure protocol. Possible reason of this discrepancy in light of paraquat toxicity is discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Parameters affecting the determination of paraquat at silver rotating electrodes using differential pulse voltammetry

    Directory of Open Access Journals (Sweden)

    A. Farahi

    2014-08-01

    Full Text Available The electrochemical determination of aqueous paraquat PQ(II by differential pulse voltammetry at a solid rotating silver electrode (RSE is described. The aim of this work is to optimize all factors that can influence this determination. Potential wave forms, potential scan parameters and deposition time were examined for their effect on the paraquat peak shape and intensity. The best responses were obtained with differential pulse voltammetry in 0.1 mol L−1 Na2SO4 as supporting electrolyte using amplitude 50 mV, scan increment 5 mV, deposition time 120 s, frequency 50 s−1 and step amplitude 0.05 V. Electrochemical and mechanical surface cleaning, aimed at removing the amount of paraquat deposited onto the silver surface, were necessary for obtaining a good performance of the electrode. Response linearity, repeatability, accuracy and detection limit were also evaluated. The obtained detection limits were 7.1 × 10−9 mol L−1 and 2.8 × 10−9 mol L−1 for peak 1 and peak 2 respectively. The relative standard deviation (RSD was found to be 1.19% in 1.0 × 10−4 mol L−1 paraquat. The applicability of the RSE for PQ(II determination in milk samples, without any sample pretreatment, was successfully demonstrated.

  14. Paraquat Exposure of Knapsack Spray Operators on Banana Plantations in Costa Rica

    NARCIS (Netherlands)

    Van Wendel de Joode BN, [No Value; De Graaf IA, [No Value; Wesseling, B; Kromhout, S.B.; de Graaf, Inge

    1996-01-01

    A study of occupational exposure to paraquat was performed among 11 knapsack spray operators at banana plantations in Costa Rica. External and internal exposures were quantified and determinants of exposure identified by measurements, observations, and interviews. Dermal exposure was measured with

  15. Characterization of the transcriptional profile in primary astrocytes after oxidative stress induced by Paraquat

    DEFF Research Database (Denmark)

    Olesen, Birgitte S. M. Thuesen; Clausen, Jørgen; Vang, Ole

    2008-01-01

    the antioxidative enzymes Mn- and CuZn superoxide dismutase (SOD) and catalase as well as the transcription factor component AP-1. Paraquat induced the expression of Mn- and CuZn SOD, catalase and decreases the expression of c-jun (a part of AP-1). Furthermore, the gene expression profiles were investigated after...

  16. Influence of age on the passage of paraquat through the blood-brain barrier in rats: a distribution and pathological examination

    International Nuclear Information System (INIS)

    Widdowson, P.S.; Farnworth, M.J.; Simpson, M.G.; Lock, E.A.

    1996-01-01

    Experiments were performed to determine the extent of paraquat entry into the brain of neonatal and elderly rats, as compared with adult rats, which may be dependent on the efficacy of the blood-brain barrier. A single, median lethal dose (20 mg/kg s.c.) of paraquat containing [14C]paraquat was administered to neonatal (10 day old), adult (3 month old) and elderly (18 month old) rats. In contrast to the adult and elderly rats where paraquat levels fell over the 24 h post-dosing period to negligible levels, paraquat concentrations in neonatal brains did not decrease with time between 0.5 and 24 h following dosing. The distribution of [14C]paraquat was measured in selective brain regions using quantitative autoradiography in all three age groups of rats, 30 min and 24 h following dosing. Autoradiography demonstrated that brain paraquat distributions were similar in the rat age groups. Most of the paraquat was confined to regions outside the blood-brain barrier and to brain regions that lack a complete blood-brain barrier e.g. dorsal hypothalamus, area postrema and the anterior olfactory bulb. Between 0.5 h and 24 h following dosing, paraquat concentrations in deeper brain structures, some distance away from the sites of entry, began to slowly increase in all the rat age groups. By 24 h following dosing, a majority of brain regions examined using quantitative autoradiography revealed significantly higher paraquat concentrations in neonatal brains as compared to brain regions of adult and elderly rats. Despite increased paraquat entry into neonatal brain, we could find no evidence for paraquat-induced neuronal cell damage following a detailed histopathological examination of perfused-fixed brains. In conclusion, impaired blood-brain barrier integrity in neonatal brain thus permitting more paraquat to enter than in adult brain, did not result in neuronal damage

  17. Modified poisoning severity score for early prognostic evaluation in acute paraquat poisoning

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    Feng-lin SONG

    2018-04-01

    Full Text Available Objective To study the applied value of modified poisoning severity score (PSS for early prognostic evaluation in acute paraquat poisoning. Methods Thirty-seven patients with acute paraquat poisoning from June 2013 to June 2016 were enrolled. The PSS score, the modified PSS score, the acute physiology and the chronic health status Ⅱ score (APACHE Ⅱ of the patients were calculated. The relationship between modified PSS and APACHE Ⅱ was analyzed. Also the factors that affect outcome were analyzed by logistic regression analysis. The work characteristic curve (ROC curve of the PSS, the modified PSS and the APECH Ⅱ were drawn and compared. Results There was a positive correlation between the risk of death and admission time, poisonous dose, the concentration of urine paraquat, and white blood cell count (P<0.05. There was a significant correlation between the modified PSS and the APACHE Ⅱ(P<0.0001. The immediate PSS score, the modified PSS score, and the APACHE Ⅱ score were significant for the prognosis of patients with acute paraquat poisoning. The area under the curve (AUC was in turn 0.774, 0.788, 0.799. Among them, the best bound of the modified PSS score was 6.5 (when the score is greater than 6.5, the risk of death is higher. Further comparison of the area under the three curves showed that there was no significant difference in the area under the ROC curve between the three scores in predicting the prognosis of death [P=0.7633(PSS-DPSS, P=0.7791(PSS-APACHE Ⅱ, P=0.8918(DPSS-APACHE Ⅱ]. Conclusion Modified PSS is helpful in early predicting the prognosis of acute paraquat poisoning. DOI: 10.11855/j.issn.0577-7402.2018.04.13

  18. Fabrication, electrochemical and catalytic properties of the nanocomposites composed of phosphomolybdic acid and viologen-functionalized multi-walled carbon nanotubes

    Science.gov (United States)

    Liu, Jiang; Wang, Jing; Chen, Meng; Qian, Dong-Jin

    2017-08-01

    Electroactive nanocomposites composed of phosphomolybdic acid (PMA) and viologen-functionalized carbon nanotubes were synthesized and used as heterogeneous catalysts for the electrocatalytic reduction of bromate. Viologen (V) was first covalently anchored on the surface of multi-walled carbon nanotubes (MWNTs) to produce positively charged MWNT-V polyelectrolyte, which was then combined with PMA through electrostatic interaction to form MWNT-V@PMA nanocomposites. Thermogravimetric analysis revealed that the organic species in the MWNT-V polyelectrolyte was about 30% in weight. Composition, structure, and morphology of the nanocomposites were investigated by using UV-vis, infrared, Raman and X-ray photoelectron spectroscopy as well as field emission transition electron microscope. The thickness of organic substituents, viologen, and PMA in the nanocomposites was approximately 10 nm covered on the surface of MWNTs. Cyclic voltammogram measurements for the casting films of MWNT-V@PMA nanocomposites revealed four couples of redox waves with cathodic potentials at about -0.56, -0.19, 0.02, 0.21 V, and anodic ones at about -0.46, -0.11, 0.12, 0.31 V (vs Ag/AgCl), respectively, among which the first one corresponded to the electron transfer process of viologens and others to that of the PMA adsorbed. Finally, the MWNT-V@PMA modified electrodes were used as heterogeneous catalysts for the electrocatalytic bromate reduction, which revealed an almost linear correction between the current density and the bromate concentrations in the concentration range from 1 to 15 mmol/l. [Figure not available: see fulltext.

  19. Molecular Cloning and Biochemical Characterization of the Iron Superoxide Dismutase from the Cyanobacterium Nostoc punctiforme ATCC 29133 and Its Response to Methyl Viologen-Induced Oxidative Stress.

    Science.gov (United States)

    Moirangthem, Lakshmipyari Devi; Ibrahim, Kalibulla Syed; Vanlalsangi, Rebecca; Stensjö, Karin; Lindblad, Peter; Bhattacharya, Jyotirmoy

    2015-12-01

    Superoxide dismutase (SOD) detoxifies cell-toxic superoxide radicals and constitutes an important component of antioxidant machinery in aerobic organisms, including cyanobacteria. The iron-containing SOD (SodB) is one of the most abundant soluble proteins in the cytosol of the nitrogen-fixing cyanobacterium Nostoc punctiforme ATCC 29133, and therefore, we investigated its biochemical properties and response to oxidative stress. The putative SodB-encoding open reading frame Npun_R6491 was cloned and overexpressed in Escherichia coli as a C-terminally hexahistidine-tagged protein. The purified recombinant protein had a SodB specific activity of 2560 ± 48 U/mg protein at pH 7.8 and was highly thermostable. The presence of a characteristic iron absorption peak at 350 nm, and its sensitivity to H2O2 and azide, confirmed that the SodB is an iron-containing SOD. Transcript level of SodB in nitrogen-fixing cultures of N. punctiforme decreased considerably (threefold) after exposure to an oxidative stress-generating herbicide methyl viologen for 4 h. Furthermore, in-gel SOD activity analysis of such cultures grown at increasing concentrations of methyl viologen also showed a loss of SodB activity. These results suggest that SodB is not the primary scavenger of superoxide radicals induced by methyl viologen in N. punctiforme.

  20. Psychiatric comorbidity and its impact on mortality in patients who attempted suicide by paraquat poisoning during 2000-2010.

    Directory of Open Access Journals (Sweden)

    Chemin Lin

    Full Text Available Paraquat poisoning is a lethal method of suicide used around the world. Although restricting its accessibility had been widely discussed, the underlying psychopathological mechanism of paraquat self-poisoning and its association with mortality have not yet been explicitly evaluated.We included all patients admitted to a tertiary general hospital in Taiwan between 2000 and 2010 following a suicide attempt by paraquat self-administration. Diagnoses were made upon psychiatric consultation based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV criteria. The risk of mortality was calculated by logistic regression with various psychiatric or medical covariates.The consultation-liaison psychiatry team assessed 157 patients who attempted suicide by paraquat poisoning. Mood disorders (54.0%, including dysthymic (26.7% and major depressive disorders (24.7%, were the most common psychiatric diagnoses among the self-poisoning patients. Among those who attempted suicide, 87 patients (58.0% died and dysthymic disorder (OR = 5.58, 95% CI: 1.13-27.69; p < 0.05 significantly increased the mortality risk after adjustment for relevant medical variables, including age, gender, severity index of paraquat poisoning (SIPP, and risk for respiratory failure.Awareness of comorbid psychiatric illnesses, especially dysthymic disorder, is vital in the prevention and treatment of suicide by paraquat poisoning.

  1. Silymarin attenuated paraquat-induced cytotoxicity in macrophage by regulating Trx/TXNIP complex, inhibiting NLRP3 inflammasome activation and apoptosis.

    Science.gov (United States)

    Liu, Zhenning; Sun, Mingli; Wang, Yu; Zhang, Lichun; Zhao, Hang; Zhao, Min

    2018-02-01

    Oxidative stress and inflammation are involved in paraquat-induced cytotoxicity. Silymarin can exert a potent antioxidative and anti-inflammatory effect in various pathophysiological processes. The aim of this current study is to explore the protective effect and potential mechanism of silymarin in paraquat-induced macrophage injury. Cells were pretreated with different doses of silymarin for 3h before exposure to paraquat. At 24h after exposure to paraquat, the paraquat-induced cytotoxicity to macrophage was measured via the MTT assay and LDH release. The levels of intracellular reactive oxygen species, GSH-Px, SOD, and lipid peroxidation product malondialdehyde were measured to evaluate the oxidative effect of paraquat. NLRP3 inflammasome and cytokines secretion in macrophage exposed to paraquat at 24h were measured via immunofluorescence microscopy, western blot or Elisa. Our results revealed that paraquat could dramatically cause cytotoxicity and reactive oxygen species generation, enhance TXNIP expression, and induce NLRP3 inflammasome activation and cytokines secretion. The pretreatment with silymarin could remarkably reduce the cytotoxicity, promote the expression of Trx and antioxidant enzymes, and suppress the TXNIP and NLRP3 inflammasome activation. In conclusion, silymarin attenuated paraquat-induced cytotoxicity in macrophage by inhibiting oxidative stress, NLRP3 inflammasome activation, cytokines secretion and apoptosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Differential Antioxidant Responses and Perturbed Porphyrin Biosynthesis after Exposure to Oxyfluorfen and Methyl Viologen in Oryza sativa

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    Nhi-Thi Pham

    2015-07-01

    Full Text Available We compared antioxidant responses and regulation of porphyrin metabolism in rice plants treated with oxyfluorfen (OF or methyl viologen (MV. Plants treated with MV exhibited not only greater increases in conductivity and malondialdehyde but also a greater decline in Fv/Fm, compared to plants treated with OF. MV-treated plants had greater increases in activities of superoxide dismutase (SOD and catalase (CAT as well as transcript levels of SODA and CATA than OF-treated plants after 28 h of the treatments, whereas increases in ascorbate peroxidase (APX activity and transcript levels of APXA and APXB were greater in OF-treated plants. Both OF- and MV-treated plants resulted in not only down-regulation of most genes involved in porphyrin biosynthesis but also disappearance of Mg-porphyrins during the late stage of photooxidative stress. By contrast, up-regulation of heme oxygenase 2 (HO2 is possibly part of an efficient antioxidant response to compensate photooxidative damage in both treatments. Our data show that down-regulated biosynthesis and degradation dynamics of porphyrin intermediates have important roles in photoprotection of plants from perturbed porphyrin biosynthesis and photosynthetic electron transport. This study suggests that porphyrin scavenging as well as strong antioxidative activities are required for mitigating reactive oxygen species (ROS production under photooxidative stress caused by OF and MV.

  3. Differential Antioxidant Responses and Perturbed Porphyrin Biosynthesis after Exposure to Oxyfluorfen and Methyl Viologen in Oryza sativa.

    Science.gov (United States)

    Pham, Nhi-Thi; Kim, Jin-Gil; Jung, Sunyo

    2015-07-21

    We compared antioxidant responses and regulation of porphyrin metabolism in rice plants treated with oxyfluorfen (OF) or methyl viologen (MV). Plants treated with MV exhibited not only greater increases in conductivity and malondialdehyde but also a greater decline in Fv/Fm, compared to plants treated with OF. MV-treated plants had greater increases in activities of superoxide dismutase (SOD) and catalase (CAT) as well as transcript levels of SODA and CATA than OF-treated plants after 28 h of the treatments, whereas increases in ascorbate peroxidase (APX) activity and transcript levels of APXA and APXB were greater in OF-treated plants. Both OF- and MV-treated plants resulted in not only down-regulation of most genes involved in porphyrin biosynthesis but also disappearance of Mg-porphyrins during the late stage of photooxidative stress. By contrast, up-regulation of heme oxygenase 2 (HO2) is possibly part of an efficient antioxidant response to compensate photooxidative damage in both treatments. Our data show that down-regulated biosynthesis and degradation dynamics of porphyrin intermediates have important roles in photoprotection of plants from perturbed porphyrin biosynthesis and photosynthetic electron transport. This study suggests that porphyrin scavenging as well as strong antioxidative activities are required for mitigating reactive oxygen species (ROS) production under photooxidative stress caused by OF and MV.

  4. [Effect of sucralfate on cytokines in rat with paraquat poisoning].

    Science.gov (United States)

    Zhu, Junbo; Yu, Yongtao; Li, Hongbo; Zheng, Fenshuang; Lin, Ruyun; Yang, Chun'ai

    2018-03-01

    To explore the effect of sucralfate on cytokines in rats with paraquat (PQ) poisoning. Seventy-two healthy male Sprague-Dawley (SD) rats were randomly divided into PQ model group, sodium bicarbonate intervention group (SB group) and sucralfate suspension gel group (LTL group), with 24 rats in each group. The rat model of PQ poisoning was reproduced by one-time intragastric administration of PQ solution 25 mg/kg. The rats in SB group and LTL group were intragastricly administrated with 5 mL×kg -1 ×d -1 of 100 g/L sodium bicarbonate or 200 g/L sucralfate at 2 hours after exposing to PQ, and the rats in PQ model group were given the same amount of sterile saline. The abdominal aortic blood of rats was collected at 1, 3, 6, and 10 days after PQ poisoning, and the levels of serum tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10) and transforming growth factor-β1 (TGF-β1) were determined by enzyme-linked immunosorbent assay (ELISA). The left lung tissue was harvested, and lung wet/dry weight (W/D) ratio was assessed. With prolonged exposure, lung W/D ratios in all the groups were increased gradually, reached the peak at 10 days, but in the SB group and LTL group, the amplitude of increase was obviously reduced, the ratios were significantly decreased at 6 days and 10 days as compared with those in PQ model group (SB group vs. PQ model group: 4.99±0.79 vs. 6.98±0.86 at 6 days, 5.61±0.36 vs. 7.36±0.95 at 10 days; LTL group vs. PQ model group: 4.61±0.24 vs. 6.98±0.86 at 6 days, 4.24±0.20 vs. 7.36±0.95 at 10 days, all P 0.05). After PQ poisoning, the levels of TNF-α, IL-10 and TGF-β1 were elevated, and reached the peak at 3 days and then decreased gradually. Compared with the PQ model group, serum TNF-α, IL-10 and TGF-β1 levels in SB group and LTL group were decreased significantly [SB group vs. PQ model group: 3-day TNF-α (ng/L) was 147.6±12.3 vs. 168.2±11.3, 3-day IL-10 (ng/L) was 65.4±3.2 vs. 115.1±9.2, 3-day TGF-β1 (ng/L) was 356.3±50.3 vs

  5. Predictive values of urine paraquat concentration, dose of poison, arterial blood lactate and APACHE II score in the prognosis of patients with acute paraquat poisoning.

    Science.gov (United States)

    Liu, Xiao-Wei; Ma, Tao; Li, Lu-Lu; Qu, Bo; Liu, Zhi

    2017-07-01

    The present study investigated the predictive values of urine paraquat (PQ) concentration, dose of poison, arterial blood lactate and Acute Physiology and Chronic Health Evaluation (APACHE) II score in the prognosis of patients with acute PQ poisoning. A total of 194 patients with acute PQ poisoning, hospitalized between April 2012 and January 2014 at the First Affiliated Hospital of P.R. China Medical University (Shenyang, China), were selected and divided into survival and mortality groups. Logistic regression analysis, receiver operator characteristic (ROC) curve analysis and Kaplan-Meier curve were applied to evaluate the values of urine paraquat (PQ) concentration, dose of poison, arterial blood lactate and (APACHE) II score for predicting the prognosis of patients with acute PQ poisoning. Initial urine PQ concentration (C0), dose of poison, arterial blood lactate and APACHE II score of patients in the mortality group were significantly higher compared with the survival group (all Ppoison and arterial blood lactate correlated with mortality risk of acute PQ poisoning (all Ppoison, arterial blood lactate and APACHE II score in predicting the mortality of patients within 28 days were 0.921, 0.887, 0.808 and 0.648, respectively. The AUC of C0 for predicting early and delayed mortality were 0.890 and 0.764, respectively. The AUC values of urine paraquat concentration the day after poisoning (Csec) and the rebound rate of urine paraquat concentration in predicting the mortality of patients within 28 days were 0.919 and 0.805, respectively. The 28-day survival rate of patients with C0 ≤32.2 µg/ml (42/71; 59.2%) was significantly higher when compared with patients with C0 >32.2 µg/ml (38/123; 30.9%). These results suggest that the initial urine PQ concentration may be the optimal index for predicting the prognosis of patients with acute PQ poisoning. Additionally, dose of poison, arterial blood lactate, Csec and rebound rate also have referential significance.

  6. Qualidade de tubérculos de batatas-semente tratados com paraquat e o desenvolvimento de uma metodologia simplificada de detecção de resíduo do herbicida Quality of seed potato tubers treated with paraquat and the development of a simplified methodology for paraquat residue detection

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    Welington Pereira

    1995-01-01

    Full Text Available O objetivo desse trabalho foi avaliar a qualidade de tubérculos de batatas-semente (Solanum tuberosum tratados com paraquat e desenvolver uma metodologia simplificada de detecção de resíduos de herbicida. Dois ensaios foram realizados no Laboratório da Ciência das Plantas Daninhas do Centro Nacional de Pesquisa de hortaliças, Brasília, DF. No experimento, tubérculos das cultivares Achat e Baronesa foram submersos em soluções de 0 e 200 ppm de paraquat ou injetados com 0,5 ml de soluções de 0 e 200 ppm do herbicida. O delineamento experimental foi inteiramente casualizado com 8 repetições e 12 tubérculos por parcela. Os tubérculos foram colocados em câmara fria, após a aplicação com paraquat, para quebra da dormência. Após a brotação dos tubérculos avaliou-se a qualidade interna dos mesmos, amostrando, posteriormente, 2 tubérculos de cada parcela para o plantio em vasos, sob condições de telado, para verificar possíveis danos no crescimento das plantas oriundas dos tubérculos tratados. Os tratamentos de imersão não provocaram, aparentemente, nenhum dano interno nos tubérculos, ou nem mesmo afetaram a nova geração, entretanto, os tubérculos injetados com paraquat foram severamente deteriorados e carbonizados, originando plantas bastante debilitadas. Esses resultados indicam que quando o paraquat for aplicado sob condições que favoreçam sua penetração ou translocação para o interior do tubérculo, atingindo os vasos e a polpa, pode danificá-lo severamente, prejudicar sua aparência, qualidade de produção e reduzir o desenvolvimento da nova geração de plantas oriundas dos tubérculos contaminados . No segundo experimento, desenvolveu-se uma metodologia simplificada para detectar resíduos de paraquat nos tubérculos através de colorimetria, visto que o paraquat é reduzido a um radical de cor azul na presença de ditionito de sódio (Na2S2O4 a 1% em meio básico, a qual se intensifica à medida que a

  7. Synthesis, solid and solution studies of paraquat dichloride calixarene complexes. Molecular modelling

    International Nuclear Information System (INIS)

    Garcia S, I.; Ramirez, F. M.

    2010-01-01

    The interaction of the herbicide paraquat dichloride (P Q, substrate) with p-tert-butylcalix arenas (L, receptor) was investigated in both the solution and solid states. The isolated paraquat calixarene complexes were characterised by UV-visible, 1 H NMR, ESI-Ms, Luminescence and IR spectroscopies and elemental analysis. The stoichiometry of complexes 1 and 2 was 1:1 (1 herbicide: 1 calixarene) and both revealed a biexponential luminescence decay with lifetimes depending on the size and the conformational particularity of the calixarenes. Molecular modelling suggested that both calixarenes interact with the herbicide through cation-π interaction. P Q in included in the p-tert butylcalix a rene cavity, a situation favoured by its pinched conformation in polar solvent while it is partially included in the p-tert butylcalix a rene cavity because of its in-out cone conformation. The theoretical results, in particular using Mopac procedures, were in agreement with the experimental findings. (Author)

  8. Synthesis, solid and solution studies of paraquat dichloride calixarene complexes. Molecular modelling

    Energy Technology Data Exchange (ETDEWEB)

    Garcia S, I.; Ramirez, F. M., E-mail: flor.ramirez@inin.gob.m [ININ, Departamento de Quimica, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2010-07-01

    The interaction of the herbicide paraquat dichloride (P Q, substrate) with p-tert-butylcalix arenas (L, receptor) was investigated in both the solution and solid states. The isolated paraquat calixarene complexes were characterised by UV-visible, {sup 1}H NMR, ESI-Ms, Luminescence and IR spectroscopies and elemental analysis. The stoichiometry of complexes 1 and 2 was 1:1 (1 herbicide: 1 calixarene) and both revealed a biexponential luminescence decay with lifetimes depending on the size and the conformational particularity of the calixarenes. Molecular modelling suggested that both calixarenes interact with the herbicide through cation-{pi} interaction. P Q in included in the p-tert butylcalix a rene cavity, a situation favoured by its pinched conformation in polar solvent while it is partially included in the p-tert butylcalix a rene cavity because of its in-out cone conformation. The theoretical results, in particular using Mopac procedures, were in agreement with the experimental findings. (Author)

  9. Removal of paraquat and linuron from water by continuous flow adsorption/ ultrafiltration membrane processes

    International Nuclear Information System (INIS)

    Zahoor, M.

    2013-01-01

    The magnetic activated carbon (MAC) was prepared, characterized and compared with powdered activated carbon (PAC) for its adsorptive parameters. Both adsorbents were then used in combination ultrafiltration (UF) membrane as pretreatment for the removal of paraquat and linuron from water. The comparison of membrane parameters like percent retention, permeate flux and backwash times for PAC/UF and MAC/UF hybrid processes showed that percent retention of paraquat and linuron was high for PAC due to its high surface area. However due to cake formation over membrane surface the decline permeate fluxes and long backwash times for PAC were observed. PAC also caused blackening of pipes and flow meter. MAC (an iron oxide and PAC composite) was removed from slurry through magnet thus no cake formation and secondary problems observed for PAC was not encountered. Also the backwash times were minimum for MAC/UF process. (author)

  10. Edaravone Decreases Paraquat Toxicity in A549 Cells and Lung Isolated Mitochondria

    OpenAIRE

    Shokrzadeh, Mohammad; Shaki, Fatemeh; Mohammadi, Ebrahim; Rezagholizadeh, Neda; Ebrahimi, Fatemeh

    2014-01-01

    Edaravone, an antioxidant and radical scavenger, showed protective effects against oxidative stress-like condition. Paraquat (PQ) is toxic herbicide considerable evidence suggests that oxidative stress and mitochondrial dysfunction contribute to PQ toxicity. In this study, protective effect of edaravone against PQ induced toxicity and reactive oxygen species (ROS) generation in A549 cells and lung isolated mitochondria were evaluated. A549 cells and lung isolated mitochondria were divided int...

  11. Rotenone and paraquat perturb dopamine metabolism: a computational analysis of pesticide toxicity

    OpenAIRE

    Qi, Zhen; Miller, Gary W.; Voit, Eberhard O.

    2013-01-01

    Pesticides, such as rotenone and paraquat, are suspected in the pathogenesis of Parkinson’s disease (PD), whose hallmark is the progressive loss of dopaminergic neurons in the substantia nigra pars compacta. Thus, compounds expected to play a role in the pathogenesis of PD will likely impact the function of dopaminergic neurons. To explore the relationship between pesticide exposure and dopaminergic toxicity, we developed a custom-tailored mathematical model of dopamine metabolism and utilize...

  12. Protective effects of exogenous β-hydroxybutyrate on paraquat toxicity in rat kidney

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Teng; Tian, Wulin; Liu, Fangning; Xie, Guanghong, E-mail: xiegh@jlu.edu.cn

    2014-05-16

    Highlights: • β-Hydroxybutyrate inhibits paraquat-induced toxicity in rat kidney. • β-Hydroxybutyrate inhibits lipid peroxidation and caspase-mediated apoptosis. • β-Hydroxybutyrate increases the activities of SOD and CAT. • The study describes a novel finding for the renoprotective ability of β-hydroxybutyrate. - Abstract: In this study, we demonstrated the protective effects of β-hydroxybutyrate (β-HB) against paraquat (PQ)-induced kidney injury and elucidated the underlying molecular mechanisms. By histological examination and renal dysfunction specific markers (serum BUN and creatinine) assay, β-HB could protect the PQ-induced kidney injury in rat. PQ-induced kidney injury is associated with oxidative stress, which was measured by increased lipid peroxidation (MDA) and decreased intracellular anti-oxidative abilities (SOD, CAT and GSH). β-HB pretreatment significantly attenuated that. Caspase-mediated apoptosis pathway contributed importantly to PQ toxicity, as revealed by the activation of caspase-9/-3, cleavage of PARP, and regulation of Bcl-2 and Bax, which were also effectively blocked by β-HB. Moreover, treatment of PQ strongly decreased the nuclear Nrf2 levels. However, pre-treatment with β-HB effectively suppressed this action of PQ. This may imply the important role of β-HB on Nrf2 pathway. Taken together, this study provides a novel finding that β-HB has a renoprotective ability against paraquat-induced kidney injury.

  13. [Enhanced Resistance of Pea Plants to Oxidative: Stress Caused by Paraquat during Colonization by Aerobic Methylobacteria].

    Science.gov (United States)

    Agafonova, N V; Doronina, N Y; Trotsenko, Yu A

    2016-01-01

    The influence of colonization of the pea (Pisum sativum L.) by aerobic methylobacteria of five different species (Methylophilus flavus Ship, Methylobacterium extorquens G10, Methylobacillus arboreus Iva, Methylopila musalis MUSA, Methylopila turkiensis Sidel) on plant resistance to paraquat-induced stresses has been studied. The normal conditions of pea colonization by methylobacteria were characterized by a decrease in the activity of antioxidant enzymes (superoxide dismutase, catalase, and peroxidases) and in the concentrations of endogenous H2O2, proline, and malonic dialdehyde, which is a product of lipid peroxidation and indicator of damage to plant cell membranes, and an increase in the activity of the photosynthetic apparatus (the content of chlorophylls a, b and carotenoids). In the presence of paraquat, the colonized plants had higher activities of antioxidant enzymes, stable photosynthetic indices, and a less intensive accumulation of the products of lipid peroxidation as compared to noncolonized plants. Thus, colonization by methylobacteria considerably increased the adaptive protection of pea plants to the paraquat-induced oxidative stress.

  14. Toxicity of paraquat in nestling birds: effects on plasma and tissue biochemistry in American kestrels

    Science.gov (United States)

    Hoffman, Daivd J.; Franson, J. Christian; Pattee, Oliver H.; Bunck, Christine M.; Murray, Helen C.

    1987-01-01

    Beginning the day after hatching, American kestrel (Falco sparverius) nestlings were orally dosed daily for 10 days with 5 μL/g of distilled water (controls), 10 mg/kg, 25 mg/kg, or 60 mg/kg of paraquat dichloride (1,1′-dimethyl-4,4′-bipyridinium dichloride) in distilled water. Forty-four percent of the nestlings receiving 60 mg/kg died after 4 days. Plasma LDH activity and total protein concentration were elevated, and plasma alkaline phosphatase activity was lower in survivors of the 60 mg/kg group at 10 days. Lung total sulfhydryl (TSH) and protein-bound sulfhydryl (PBSH) concentrations were significantly higher in the 10 mg/kg, 25 mg/kg, or 60 mg/kg groups. Lung DNA, RNA, protein, and hydroxyproline (collagen) concentrations were not significantly affected by treatment. Liver NPSH was lower in the 60 mg/kg group while liver glycogen concentration was not affected by treatment. Kidney DNA, RNA, and RNA to protein concentration ratio were higher in the 25 mg/kg or 60 mg/kg groups. These findings in combination with recently reported effects on growth and histopathology suggest that altricial nestling kestrels are more sensitive to paraquat exposure than young or adult birds of precocial species. From a comparative viewpoint, lungs of nestling kestrels are less sensitive to paraquat than mammalian lungs.

  15. Paraquat adsorption on NaX and Al-MCM-41.

    Science.gov (United States)

    Rongchapo, Wina; Deekamwong, Krittanun; Loiha, Sirinuch; Prayoonpokarach, Sanchai; Wittayakun, Jatuporn

    2015-01-01

    The aim of this work is to determine paraquat adsorption capacity of zeolite NaX and Al-MCM-41. All adsorbents were synthesized by hydrothermal method using rice husk silica. For Al-MCM-41, aluminum (Al) was added to the synthesis gel of MCM-41 with Al content of 10, 15, 20 and 25 wt%. The faujasite framework type of NaX and mesoporous characteristic of Al-MCM-41 were confirmed by X-ray diffraction. Surface area of all adsorbents determined by N2 adsorption-desorption analysis was higher than 650 m2/g. Al content and geometry were determined by X-ray fluorescence and 27Al nuclear magnetic resonance, respectively. Morphology of Al-MCM-41 were studied by transmission electron microscopy; macropores and defects were observed. The paraquat adsorption experiments were conducted using a concentration range of 80-720 mg/L for NaX and 80-560 mg/L for Al-MCM-41. The paraquat adsorption isotherms from all adsorbents fit well with the Langmuir model. The adsorption capacity of NaX was 120 mg/g-adsorbent. Regarding Al-MCM-41, the 10% Al-MCM-41 exhibited the lowest capacity of 52 mg/g-adsorbent while the other samples had adsorption capacity of 66 mg/g-adsorbent.

  16. ADSORPTION OF PARAQUAT DICHLORIDE TO KAOLIN PARTICLES AND TO MIXTURES OF KAOLIN AND HEMATITE PARTICLES

    Directory of Open Access Journals (Sweden)

    Dina Alexandra Martins

    2015-03-01

    Full Text Available Deliberate contamination with pesticides is a potential risk to water security, due to the availability of these contaminants and the fact that they do not need special expertise to handle or apply. Adsorption of the herbicide paraquat from an aqueous solution to suspended particles of kaolin and kaolin/hematite mixture was investigated by kinetic and equilibrium assays, taking into consideration several parameters such as initial pH, sorbent dosage and agitation speed. The results showed that the adsorption process is quite fast, reaching an 18% reduction in paraquat concentration in a very short period of time. The addition of hematite particles to kaolin suspension had no apparent effect on the maximum amount of paraquat adsorbed. Kinetic parameters were determined by fitting the pseudo-second order model to the experimental data (correlation coefficients close to 1. Isotherm studies indicate an inhibitory effect, promoted by hematite particles, that was not detected in the adsorption assays. Equilibrium data was best adjusted using the Langmuir model which yielded higher correlation coefficient values and smaller normalized standard deviations.

  17. Paraquat induced lung injury: long-term follow-up of HRCT

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Tong; Kim, Hyun Cheol; Bae, Won Kyung; Kim, Il Young; Im, Han Hyek [Soonchunhyang Univ., Chunan (Korea, Republic of)

    2004-03-01

    To determine the long-term follow-up CT findings of paraquat-induced lung injury. Six patients who ingested paraquat underwent sequential follow-up CT scanning during a period of at least six months, and the results were analysed. Scans were obtained 1-6 (mean, 3.3) time during a 7-84 (mean, 25.7) months period, and the findings at 1-2 months, 3-12 months, 1-2 years, 2-3 years and more than above 7 years after poisoning were analyzed. We observed irregular-shaped areas of consolidation with traction bronchiectasis at 1-2 months (5/5), irregular-shaped consolidation and ground-glass opacity (5/5) at 3-12 months, and irregular-shaped consolidations/ground-glass opacity (4/5) and focal honeycombing (1/5) one year later. In the same patients, follow-up CT scans showed that some areas of focal consolidation could not be visualized and the radio-opacity of the lesions had decreased. The HRCT findings of paraquat-induced lung injury were irregular shaped areas of consolidation 1-2 months after ingestion, and irregular-shaped consolidation and ground-glass opacity or focal honeycombing 3-12 months later. At this thim slight improvement was observed.

  18. A high sensitive ion pairing probe (the interaction of pyrenetetrasulphonate and methyl viologen): Salt and temperature dependences and applications

    Energy Technology Data Exchange (ETDEWEB)

    Santana, Jeferson [Departamento de Bioquímica e Departamento de Química, Instituto de Química, Universidade de São Paulo, SP (Brazil); Perez, Katia R. [Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo-SP (Brazil); Pisco, Thiago B.; Pavanelli, David D.; Briotto Filho, Décio; Rezende, Daisy [Departamento de Bioquímica e Departamento de Química, Instituto de Química, Universidade de São Paulo, SP (Brazil); Rezende Triboni, Eduardo [Universidade Nove de Julho, São Paulo, São Paulo-SP (Brazil); Chagas Alves Lima, Francisco das [Coordenação de Química, Universidade Estadual do Piauí, Teresina-PI (Brazil); Lopes Magalhães, Janildo [Departamento de Química, Centro de Ciências da Natureza, Universidade Federal do Piauí, Centro de Ciências da Natureza, Teresina, PI (Brazil); Midea Cuccovia, Iolanda [Departamento de Bioquímica e Departamento de Química, Instituto de Química, Universidade de São Paulo, SP (Brazil); and others

    2014-07-01

    The interaction between pyrenetetrasulphonate (PTS) and methyl viologen (MV{sup 2+}) leads to a 1:1 charge transfer complex (CTC) in the concentration range below mmol L{sup −1} of the ligands. Quantum mechanical calculations show the 1:1 complex having the planar moiety of PTS and the charges of the sulfonate groups stabilized by the twisted rings of the positively charged MV{sup 2+} species. The peculiar nature of PTS includes high fluorescence quantum yield (∼1), clear specular UV–vis spectra and fluorescence emission images, as well similar S{sub 2}←S{sub 0} and S{sub 3}←S{sub 0} transitions as those of S{sub 1}←S{sub 0,} all of them exhibiting well resolved vibrational structure. MV{sup 2+} has well known electron-accepting properties that favor the complexation. These features were studied as a function of salt concentration and temperature dependences allowing a detailed comprehension of static and dynamic association processes. Quantum mechanical calculations show the 1:1 stabilization of PTS/MV{sup 2+}. In addition the effect of urea on the CTC equilibrium is presented, as expected the additive acts towards the non-complexed species (solvated free ions). The fluorescence quenching of MV{sup 2+}over PTS highlights is one of the applications of this effect for giant vesicles characterization. - Highlights: • We determined the details of PTS/MV{sup 2+} 1:1 complex formation. • Ground and excited states formation is operative. • Ion pairing effects due to urea effect are shown. • Vesicle formation is illustrated by the pair.

  19. Mitigating effects of pollen during paraquat exposure on gene expression and pathogen prevalence in Apis mellifera L.

    Science.gov (United States)

    de Mattos, Igor Medici; Soares, Ademilson E E; Tarpy, David R

    2018-01-01

    Honey bee (Apis mellifera L.) populations have been experiencing notable mortality in Europe and North America. No single cause has been identified for these dramatic losses, but rather multiple interacting factors are likely responsible (such as pesticides, malnutrition, habitat loss, and pathogens). Paraquat is one of the most widely used non-selective herbicides, especially in developing countries. This herbicide is considered slightly toxic to honey bees, despite being reported as a highly effective inducer of oxidative stress in a wide range of living systems. Here, we test the effects of paraquat on the expression of detoxification and antioxidant-related genes, as well as on the dynamics of pathogen titers. Moreover, we tested the effects of pollen as mitigating factor to paraquat exposure. Our results show significant changes in the expression of several antioxidant-related and detoxification-related genes in the presence of paraquat, as well as an increase of pathogens titers. Finally, we demonstrate a mitigating effect of pollen through the up-regulation of specific genes and improvement of survival of bees exposed to paraquat. The presence of pollen in the diet was also correlated with a reduced prevalence of Nosema and viral pathogens. We discuss the importance of honey bees' nutrition, especially the availability of pollen, on colony losses chronically reported in the USA and Europe.

  20. Curcumin attenuates paraquat-induced cell death in human neuroblastoma cells through modulating oxidative stress and autophagy.

    Science.gov (United States)

    Jaroonwitchawan, Thiranut; Chaicharoenaudomrung, Nipha; Namkaew, Jirapat; Noisa, Parinya

    2017-01-01

    Paraquat is a neurotoxic agent, and oxidative stress plays an important role in neuronal cell death after paraquat exposure. In this study, we assessed the neuroprotective effect of curcumin against paraquat and explored the underlying mechanisms of curcumin in vitro. Curcumin treatment prevented paraquat-induced reactive oxygen species (ROS) and apoptotic cell death. Curcumin also exerted a neuroprotective effect by increasing the expression of anti-apoptotic and antioxidant genes. The pretreatment of curcumin significantly decreased gene expression and protein production of amyloid precursor protein. The activation of autophagy process was found defective in paraquat-induced cells, indicated by the accumulation and reduction of LC3I/II. Noteworthy, curcumin restored LC3I/II expression after the pretreatment. Collectively, curcumin demonstrated as a prominent suppressor of ROS, and could reverse autophagy induction in SH-SY5Y cells. The consequences of this were the reduction of APP production and prevention of SH-SY5Y cells from apoptosis. Altogether, curcumin potentially serves as a therapeutic agent of neurodegenerative diseases, associated with ROS overproduction and autophagy dysfunction. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  1. The reduction of nitrate, nitrite and hydroxylamine to ammonia by enzymes from Cucurbita pepo L. in the presence of reduced benzyl viologen as electron donor

    Science.gov (United States)

    Cresswell, C. F.; Hageman, R. H.; Hewitt, E. J.; Hucklesby, D. P.

    1965-01-01

    1. Enzyme systems from Cucurbita pepo have been shown to catalyse the reduction of nitrite and hydroxylamine to ammonia in yields about 90–100%. 2. Reduced benzyl viologen serves as an efficient electron donor for both systems. Activity of the nitrite-reductase system is directly related to degree of dye reduction when expressed in terms of the function for oxidation–reduction potentials, but appears to decrease to negligible activity below about 9% dye reduction. 3. NADH and NADPH alone produce negligible nitrite loss, but NADPH can be linked to an endogenous diaphorase system to reduce nitrite to ammonia in the presence of catalytic amounts of benzyl viologen. 4. The NADH– or NADPH–nitrate-reductase system that is also present can accept electrons from reduced benzyl viologen, but shows relationships opposite to that for the nitrite-reductase system with regard to effect of degree of dye reduction on activity. The product of nitrate reduction may be nitrite alone, or nitrite and ammonia, or ammonia alone, according only to the degree of dye reduction. 5. The relative activities of nitrite-reductase and hydroxylamine-reductase systems show different relationships with degree of dye reduction and may become reversed in magnitude when effects of degree of dye reduction are tested over a suitable range. 6. Nitrite severely inhibits the rate of reduction of hydroxylamine without affecting the yield of ammonia as a percentage of total substrate loss, but hydroxylamine has a negligible effect on the activity of the nitrite-reductase system. 7. The apparent Km for nitrite (1 μm) is substantially less than that for hydroxylamine, for which variable values between 0·05 and 0·9mm (mean 0·51 mm) have been observed. 8. The apparent Km values for reduced benzyl viologen differ for the nitrite-reductase and hydroxylamine-reductase systems: 60 and 7·5 μm respectively. 9. It is concluded that free hydroxylamine may not be an intermediate in the reduction of nitrite

  2. Intense Chiroptical Switching in a Dicationic Helicene-Like Derivative: Exploration of a Viologen-Type Redox Manifold of a Non-Racemic Helquat

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Lubomír; Bednárová, Lucie; Štěpánek, Petr; Slavíček, P.; Vávra, Jan; Hromadová, Magdaléna; Dlouhá, Helena; Tarábek, Ján; Teplý, Filip

    2014-01-01

    Roč. 136, č. 31 (2014), s. 10826-10829 ISSN 0002-7863 R&D Projects: GA ČR GA13-19213S Grant - others:GA ČR(CZ) GA13-34168S; GA MŠk(CZ) ED3.2.00/08.0144 Institutional support: RVO:61388963 ; RVO:61388955 Keywords : helicenoids * helquats * helical cations * ECD spectra * redox switching * chiroptical properties * helicene-viologen hybrids Subject RIV: CC - Organic Chemistry Impact factor: 12.113, year: 2014

  3. Aspectos gerais e diagnóstico clinicolaboratorial da intoxicação por paraquat General aspects and clinical laboratorial diagnostic of poisoning by paraquat

    Directory of Open Access Journals (Sweden)

    Gabriela Cristina Schmitt

    2006-08-01

    Full Text Available INTRODUÇÃO: O paraquat, herbicida amplamente utilizado na agricultura, é um produto perigoso, pois pode causar intoxicações fatais, principalmente pela falta de antídoto eficaz para reversão do quadro clínico. Fisiopatologia: Os efeitos toxicológicos são decorrentes da indução ao estresse oxidativo. O órgão-alvo principal é o pulmão, que pode apresentar edema, hemorragia, inflamação intersticial e fibrose, culminando com falência respiratória grave e morte. Além disso, é nefrotóxico, hepatotóxico, miotóxico e neurotóxico. TRATAMENTO: Além de visar a diminuição da absorção e estimular a excreção do paraquat absorvido, o tratamento da intoxicação atualmente é baseado em medidas que diminuam o estresse oxidativo utilizando substâncias antioxidantes e, conseqüentemente, revertam o quadro toxicológico instalado, especialmente o pulmonar. MÉTODOS DIAGNÓSTICOS: Entre as metodologias quantitativas disponíveis, os métodos cromatográficos são os mais relatados para materiais biológicos. Porém, a eletroforese capilar e os imunoensaios podem ser utilizados. Os imunoensaios destacam-se pela praticidade laboratorial, pois os cromatográficos e eletroforéticos não são encontrados comumente em laboratórios hospitalares. Por outro lado, uma reação simples e rápida de caracterização urinária com ditionito de sódio é muito realizada, pois é preditiva na suspeita de intoxicações agudas. CONCLUSÃO: Diante do alto potencial de morbimortalidade nas intoxicações por paraquat, a reversão dos danos pulmonares com uso de antioxidantes vem sendo muito estudada, porém não há o estabelecimento de um antídoto específico. No diagnóstico laboratorial, métodos cromatográficos, eletroforéticos e imunológicos são usados para quantificá-lo, contudo a reação urinária com ditionito ainda é valiosa na rotina da toxicologia clínica.INTRODUCTION: Paraquat is a herbicide widely used in agriculture. It is a

  4. Search for a one-electron reduction of the cation radical of an "extended viologen," p-phenylene-bis-4,4´(1-aryl-2,6-diphenylpyridinium)

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Lubomír; Fiedler, Jan; Hromadová, Magdaléna; Gál, Miroslav; Valášek, M.; Pecka, J.; Michl, J.

    2006-01-01

    Roč. 153, č. 11 (2006), E179-E183 ISSN 0013-4651 R&D Projects: GA AV ČR IAA400400505; GA AV ČR KJB400400603; GA MŠk LC510; GA MŠk OC 140 Grant - others:U.S. National Science Foundation(US) CHE-0446688; US National Science Foundation(US) OISE 0532040 Institutional research plan: CEZ:AV0Z40400503 Keywords : aromatic poly(pyridinium salt)s * methyl viologen * aqueous-solution * heptyl viologen Subject RIV: CG - Electrochemistry Impact factor: 2.387, year: 2006

  5. [Clinical effect of compound monoammonium glycyrrhizinate combined with dandelion in treatment of acute paraquat poisoning].

    Science.gov (United States)

    Zhao, Y; Jian, X D

    2016-07-20

    Objective: To investigate the clinical effect of compound monoammonium glycyrrhizinate combined with dandelion in the treatment of acute paraquat poisoning. Methods: A total of 80 patients with acute paraquat poisoning who were admitted to our hospital were enrolled as study subjects and randomly divided into routine treatment group (38 patients) and traditional Chinese medicine (TCM) group (42 patients) . The patients in the TCM group were given compound monoammonium glycyrrhizinate and dandelion in addition to the treatment in the control group. Serum alanine aminotransferase (ALT) , total bilirubin (TBil) , blood urea nitrogen (BUN) , creatinine (Cr) , and arterial blood lactate (Lac) and partial pressure of oxygen (PaO 2 ) during different time periods on day 3, 7, and 9 of treatment were observed in both groups, and ulceration of oral mucosa, pulmonary fibrosis, multiple organ dysfunction syndrome (MODS) , and mortality were compared between the two groups. Results: On days 3, 7, and 9 of treatment, the routine treatment group had significantly higher serum ALT, TBil, BUN, Cr, and arterial blood Lac than the TCM group. The routine treatment group had significantly lower arterial blood PaO 2 than the TCM group, while the TCM group had significantly lower incidence rates of ulceration of oral mucosa, pulmonary fibrosis, and MODS and a significantly lower mortality rate than the routine treatment group ( P treatment of patients with acute paraquat poisoning, compound monoammonium glycyrrhizinate combined with dandelion can effectively improve organ function, reduce the incidence of pulmonary fibrosis and MODS, improve the healing rate of oral ulcer, improve prognosis, and reduce mortality rate.

  6. Tualang Honey Protects the Rat Midbrain and Lung against Repeated Paraquat Exposure

    OpenAIRE

    Tang, Suk Peng; Kuttulebbai Nainamohamed Salam, Sirajudeen; Jaafar, Hasnan; Gan, Siew Hua; Muzaimi, Mustapha; Sulaiman, Siti Amrah

    2017-01-01

    Paraquat (PQ) is a dopaminergic neurotoxin and a well-known pneumotoxicant that exerts its toxic effect via oxidative stress-mediated cellular injuries. This study investigated the protective effects of Tualang honey against PQ-induced toxicity in the midbrain and lungs of rats. The rats were orally treated with distilled water (2?mL/kg/day), Tualang honey (1.0?g/kg/day), or ubiquinol (0.2?g/kg/day) throughout the experimental period. Two weeks after the respective treatments, the rats were i...

  7. Effect of low doses of herbicide paraquat on antioxidant defense in Drosophila

    Czech Academy of Sciences Publication Activity Database

    Krůček, Tomáš; Korandová, Michala; Szakosová, K.; Šerý, Michal; Čapková Frydrychová, Radmila

    2015-01-01

    Roč. 88, č. 4 (2015), s. 235-248 ISSN 0739-4462 R&D Projects: GA ČR GA14-07172S Grant - others:GA JU(CZ) 038/2014/P; GA JU(CZ) 052/2013/P; European Union Seventh Framework Programme(CZ) 316304 Program:FP7 Institutional support: RVO:60077344 Keywords : Drosophila * oxidative stress * paraquat Subject RIV: CE - Biochemistry Impact factor: 1.357, year: 2015 http://onlinelibrary.wiley.com/doi/10.1002/arch.21222/epdf

  8. Paraquat administration in Drosophila for use in metabolic studies of oxidative stress.

    Science.gov (United States)

    Rzezniczak, T Z; Douglas, L A; Watterson, J H; Merritt, T J S

    2011-12-15

    Paraquat (PQ) is widely used in the laboratory to induce in vivo oxidative stress, particularly in the fruit fly, Drosophila melanogaster. PQ administration to the fly traditionally involves feeding in a 1% sucrose solution; however, a diet high in sucrose can itself be stressful. We examined a novel method of PQ administration: incorporation into the fly's standard cornmeal-sucrose-yeast diet. This method successfully delivers PQ to the fly at concentrations similar to those of the traditional method but with fewer possibly confounding complications. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. Age and Chronicity of Administration Dramatically Influenced the Impact of Low Dose Paraquat Exposure on Behavior and Hypothalamic-Pituitary-Adrenal Activity

    Directory of Open Access Journals (Sweden)

    Chris A. Rudyk

    2017-07-01

    Full Text Available Little is known of the age-dependent and long-term consequences of low exposure levels of the herbicide and dopaminergic toxicant, paraquat. Thus, we assessed the dose-dependent effects of paraquat using a typical short-term (3 week exposure procedure, followed by an assessment of the effects of chronic (16 weeks exposure to a very low dose (1/10th of what previously induced dopaminergic neuronal damage. Short term paraquat treatment dose-dependently induced deficits in locomotion, sucrose preference and Y-maze performance. Chronic low dose paraquat treatment had a very different pattern of effects that were also dependent upon the age of the animal: in direct contrast to the short-term effects, chronic low dose paraquat increased sucrose consumption and reduced forced swim test (FST immobility. Yet these effects were age-dependent, only emerging in mice older than 13 months. Likewise, Y-maze spontaneous alternations and home cage activity were dramatically altered as a function of age and paraquat chronicity. In both the short and long-term exposure studies, increased corticosterone and altered hippocampal glucocorticoid receptor (GR levels were induced by paraquat, but surprisingly these effects were blunted in the older mice. Thus, paraquat clearly acts as a systemic stressor in terms of corticoid signaling and behavioral outcomes, but that paradoxical effects may occur with: (a repeated exposure at; (b very low doses; and (c older age. Collectively, these data raise the possibility that repeated “hits” with low doses of paraquat in combination with aging processes might have promoted compensatory outcomes.

  10. Wld(S reduces paraquat-induced cytotoxicity via SIRT1 in non-neuronal cells by attenuating the depletion of NAD.

    Directory of Open Access Journals (Sweden)

    Qiujing Yu

    Full Text Available Wld(S is a fusion protein with NAD synthesis activity, and has been reported to protect axonal and synaptic compartments of neurons from various mechanical, genetic and chemical insults. However, whether Wld(S can protect non-neuronal cells against toxic chemicals is largely unknown. Here we found that Wld(S significantly reduced the cytotoxicity of bipyridylium herbicides paraquat and diquat in mouse embryonic fibroblasts, but had no effect on the cytotoxicity induced by chromium (VI, hydrogen peroxide, etoposide, tunicamycin or brefeldin A. Wld(S also slowed down the death of mice induced by intraperitoneal injection of paraquat. Further studies demonstrated that Wld(S markedly attenuated mitochondrial injury including disruption of mitochondrial membrane potential, structural damage and decline of ATP induced by paraquat. Disruption of the NAD synthesis activity of Wld(S by an H112A or F116S point mutation resulted in loss of its protective function against paraquat-induced cell death. Furthermore, Wld(S delayed the decrease of intracellular NAD levels induced by paraquat. Similarly, treatment with NAD or its precursor nicotinamide mononucleotide attenuated paraquat-induced cytotoxicity and decline of ATP and NAD levels. In addition, we showed that SIRT1 was required for both exogenous NAD and Wld(S-mediated cellular protection against paraquat. These findings suggest that NAD and SIRT1 mediate the protective function of Wld(S against the cytotoxicity induced by paraquat, which provides new clues for the mechanisms underlying the protective function of Wld(S in both neuronal and non-neuronal cells, and implies that attenuation of NAD depletion may be effective to alleviate paraquat poisoning.

  11. Foliar Desiccators Glyphosate, Carfentrazone, and Paraquat Affect the Technological and Chemical Properties of Cowpea Grains.

    Science.gov (United States)

    Lindemann, Igor da Silva; Lang, Gustavo Heinrich; Hoffmann, Jessica Fernanda; Rombaldi, Cesar Valmor; de Oliveira, Maurício; Elias, Moacir Cardoso; Vanier, Nathan Levien

    2017-08-16

    The effects of the use of glyphosate (GLY), glyphosate plus carfentrazone (GLY/CAR), and paraquat (PAR) as plant desiccators on the technological and chemical properties of cowpea grains were investigated. All studied desiccants provided lower cooking time to freshly harvested cowpea. However, the coat color of PAR- and GLY/CAR-treated cowpea was reddish in comparison to the control treatment. Principal component analysis (PCA) from liquid chromatography-mass spectrometry (LC-MS) data sets showed a clear distinction among cowpea from the different treatments. Catechin-3-glucoside and epicatechin significantly contributed for discriminating GLY-treated cowpea, while citric acid was responsible for discriminating GLY/CAR-treated cowpea. Quercetin derivative and gluconic acid were responsible for discriminating control treatment. Residual glyphosate and paraquat content was higher than the maximum limits allowed by Codex Alimentarius and the European Union Commission. Improvements in the technological and chemical properties of cowpea may not be overlapped by the risks that those desiccants exhibit when exceeding the maximum limits of tolerance in food.

  12. Antioxidant effects of selenium on lung injury in paraquat intoxicated rats

    Science.gov (United States)

    Kim, K.S.; Suh, G.J.; Kwon, W.Y.; Kwak, Y.H.; Lee, Kenneth; Lee, H.J.; Jeong, K.Y.; Lee, M.W.

    2012-01-01

    CONTEXT: Paraquat (PQ) causes lethal intoxication by inducing oxidant injury to the lung. Selenium is a cofactor for glutathione peroxidase (GPx), which is one of the major endogenous antioxidant enzymes. OBJECTIVE: To determine whether selenium post-treatment activates GPx, decreases lung injury, and improves survival in PQ intoxicated rats. MATERIALS AND METHODS: Male Spraque-Dawley rats were categorized into three groups: sham (n = 6), PQ (n = 12), and PQ + Se (n = 12). In the PQ and PQ + Se groups, 50 mg/kg of PQ was administered intraperitoneally. After 10 minutes, 60 μg/kg of Se (PQ + Se) or saline (PQ) was administered via the tail vein. Six rats per group were euthanized 6 hours or 24 hours later. Lung tissues were harvested for the measurement of GPx activity, reduced glutathione (GSH), glutathione disulfide (GSSG) and malondialdehyde (MDA) and for histological analysis. Using separated set of rats, survival of PQ (n = 10) and PQ + Se (n = 10) were observed for 72 hours. RESULTS: GPx activity in the PQ group at the 6-hour and 24-hour time points was lower than in the sham group (p CONCLUSION: Single dose of selenium post-treatment activates GPx and attenuates lipid peroxidation and lung injury early after paraquat intoxication, but does not improve 72 hours of survival.

  13. Paraquat initially damages cochlear support cells leading to anoikis-like hair cell death.

    Science.gov (United States)

    Zhang, Jianhui; Sun, Hong; Salvi, Richard; Ding, Dalian

    2018-07-01

    Paraquat (PQ), one of the most widely used herbicides, is extremely dangerous because it generates the highly toxic superoxide radical. When paraquat was applied to cochlear organotypic cultures, it not only damaged the outer hair cells (OHCs) and inner hair cells (IHCs), but also caused dislocation of the hair cell rows. We hypothesized that the dislocation arose from damage to the support cells (SCs) that anchors hair cells within the epithelium. To test this hypothesis, rat postnatal cochlear cultures were treated with PQ. Shortly after PQ treatment, the rows of OHCs separated from one another and migrated radially away from IHCs suggesting loss of cell-cell adhesion that hold the hair cells in proper alignment. Hair cells dislocation was associated with extensive loss of SCs in the organ of Corti, loss of tympanic border cells (TBCs) beneath the basilar membrane, the early appearance of superoxide staining and caspase-8 labeling in SCs below the OHCs and disintegration of E-cadherin and β-catenin in the organ of Corti. Damage to the TBCs and SCs occurred prior to loss of OHC or IHC loss suggesting a form of detachment-induced apoptosis referred to as anoikis. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Use of Cdse/ZnS quantum dots for sensitive detection and quantification of paraquat in water samples

    Energy Technology Data Exchange (ETDEWEB)

    Durán, Gema M. [Department of Analytical Chemistry and Food Technology, University of Castilla – La Mancha, Avenida Camilo José Cela, 10, 13004 Ciudad Real (Spain); IRICA (Regional Institute of Applied Scientific Research), Avenida Camilo José Cela, s/n., 13071 Ciudad Real (Spain); Contento, Ana M. [Department of Analytical Chemistry and Food Technology, University of Castilla – La Mancha, Avenida Camilo José Cela, 10, 13004 Ciudad Real (Spain); Ríos, Ángel, E-mail: Angel.Rios@uclm.es [Department of Analytical Chemistry and Food Technology, University of Castilla – La Mancha, Avenida Camilo José Cela, 10, 13004 Ciudad Real (Spain)

    2013-11-01

    Graphical abstract: -- Highlights: •Analytical use of CdSe/ZnS quantum dots. •Methodology for water solubilization of CdSe/ZnS QDs. •Sensitive and selective reaction with paraquat herbicide. •Application to water samples. -- Abstract: Based on the highly sensitive fluorescence change of water-soluble CdSe/ZnS core-shell quantum dots (QD) by paraquat herbicide, a simple, rapid and reproducible methodology was developed to selectively determine paraquat (PQ) in water samples. The methodology enabled the use of simple pretreatment procedure based on the simple water solubilization of CdSe/ZnS QDs with hydrophilic heterobifunctional thiol ligands, such as 3-mercaptopropionic acid (3-MPA), using microwave irradiation. The resulting water-soluble QDs exhibit a strong fluorescence emission at 596 nm with a high and reproducible photostability. The proposed analytical method thus satisfies the need for a simple, sensible and rapid methodology to determine residues of paraquat in water samples, as required by the increasingly strict regulations for health protection introduced in recent years. The sensitivity of the method, expressed as detection limits, was as low as 3.0 ng L{sup −1}. The lineal range was between 10–5 × 10{sup 3} ng L{sup −1}. RSD values in the range of 71–102% were obtained. The analytical applicability of proposed method was demonstrated by analyzing water samples from different procedence.

  15. Use of Cdse/ZnS quantum dots for sensitive detection and quantification of paraquat in water samples

    International Nuclear Information System (INIS)

    Durán, Gema M.; Contento, Ana M.; Ríos, Ángel

    2013-01-01

    Graphical abstract: -- Highlights: •Analytical use of CdSe/ZnS quantum dots. •Methodology for water solubilization of CdSe/ZnS QDs. •Sensitive and selective reaction with paraquat herbicide. •Application to water samples. -- Abstract: Based on the highly sensitive fluorescence change of water-soluble CdSe/ZnS core-shell quantum dots (QD) by paraquat herbicide, a simple, rapid and reproducible methodology was developed to selectively determine paraquat (PQ) in water samples. The methodology enabled the use of simple pretreatment procedure based on the simple water solubilization of CdSe/ZnS QDs with hydrophilic heterobifunctional thiol ligands, such as 3-mercaptopropionic acid (3-MPA), using microwave irradiation. The resulting water-soluble QDs exhibit a strong fluorescence emission at 596 nm with a high and reproducible photostability. The proposed analytical method thus satisfies the need for a simple, sensible and rapid methodology to determine residues of paraquat in water samples, as required by the increasingly strict regulations for health protection introduced in recent years. The sensitivity of the method, expressed as detection limits, was as low as 3.0 ng L −1 . The lineal range was between 10–5 × 10 3 ng L −1 . RSD values in the range of 71–102% were obtained. The analytical applicability of proposed method was demonstrated by analyzing water samples from different procedence

  16. Resistance to oxidative stress induced by paraquat correlates well with both decreased and increased lifespan in Drosophila melanogaster

    NARCIS (Netherlands)

    Vermeulen, CJ; Van De Zande, L; Bijlsma, R

    2005-01-01

    There is increasing support for the notion that genetic variation for lifespan, both within and between species, is correlated with variation in the efficiency of the free radical scavenging system and the ability to withstand oxidative stress. In Drosophila, resistance to dietary paraquat, a free

  17. Toxicological responses on cytochrome P450 and metabolic transferases in liver of goldfish (Carassius auratus) exposed to lead and paraquat.

    Science.gov (United States)

    Xu, Xiaoming; Cui, Zhaojie; Wang, Xinlei; Wang, Xixin; Zhang, Su

    2018-04-30

    As the producer of reactive oxygen species (ROS), both lead (Pb) and paraquat (PQ) can generate serious oxidative stress in target organs which result in irreversible toxic effects on organisms. They can disturb the normal catalytic activities of many enzymes by means of different toxicity mechanism. The changed responses of enzymes are frequently used as the biomarkers for indicating the relationship between toxicological effects and exposure levels. In this work, goldfish was exposed to a series of test groups containing lead and paraquat in the range of 0.05-10mg/L, respectively. Four hepatic enzyme activities, including 7-ethoxyresorufinO-deethylase (EROD), 7-benzyloxy-4-trifluoromethyl-coumarin-O-debenzyloxylase (BFCOD), glutathione S-transferase (GST) and UDP-glucuronosyltransferase (UGT) were determined after 1, 7, 14, 28 days exposure. The results showed that the activities of EROD and BFCOD in fish were significantly inhibited in response to paraquat at all exposure levels during the whole experiment. Similarly, the inhibitory effects of lead exposure on BFCOD activity were found in our study, while different responses of lead on EROD were observed. There were no significant differences on EROD activity under lower concentrations of lead (less than 0.1mg/L) before 14 days until an obvious increase was occurred for the 0.5mg/L lead treatment group at day 14. Furthermore, lead showed stronger inhibition on GST activity than paraquat when the concentrations of the two toxicants were more than 0.5mg/L. However, the similar dose and time-dependent manners of UGT activity were found under lead and paraquat exposure. Our results indicated that higher exposure levels and longer accumulations caused inhibitory effects on the four enzymes regardless of lead or paraquat stress. In addition, the responses of phase I enzymes were more sensitive than that of phase II enzymes and they may be served as the acceptable biomarkers for evaluating the toxicity effects of both

  18. Intoxicação grave por paraquat: achados clínicos e radiológicos em um sobrevivente Severe paraquat poisoning: clinical and radiological findings in a survivor

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    Fábio Fernandes Neves

    2010-08-01

    Full Text Available O paraquat é um herbicida não seletivo que possui grande importância toxicológica, sendo associado a altas taxas de letalidade, devidas principalmente à insuficiência respiratória. Este é o relato do caso de um homem de 22 anos admitido no departamento de emergência com queixa de dor de garganta, disfagia, hemoptise e dor retroesternal. Ele relatava a ingestão de cerca de 50 mL de uma solução de paraquat quatro dias antes da admissão hospitalar. A TC de tórax exibia opacidades pulmonares, pneumomediastino, pneumotórax e enfisema subcutâneo. O paciente foi submetido a dois ciclos de terapia imunossupressora com ciclofosfamida, metilprednisolona e dexametasona. Os parâmetros gasométricos progressivamente melhoraram, e o paciente recebeu alta hospitalar após quatro semanas. Decorridos quatro meses da alta, o paciente foi submetido a controles clínico e tomográfico, os quais confirmaram a melhora clínica. Apresentamos também uma revisão sucinta da literatura, bem como uma discussão do processo de decisão terapêutica para intoxicação grave por paraquat.Paraquat is a nonselective contact herbicide of great toxicological importance, being associated with high mortality rates, mainly due to respiratory failure. We report the case of a 22-year-old male admitted to the emergency room with a sore throat, dysphagia, hemoptysis, and retrosternal pain after the ingestion of 50 mL of a paraquat solution, four days prior to admission. Chest CT scans revealed pulmonary opacities, pneumomediastinum, pneumothorax, and subcutaneous emphysema. The patient was submitted to two cycles of immunosuppressive therapy with cyclophosphamide, methylprednisolone, and dexamethasone. The pulmonary gas exchange parameters gradually improved, and the patient was discharged four weeks later. The clinical and tomographic follow-up evaluations performed at four months after discharge showed that there had been further clinical improvement. We also

  19. Efeito de doses reduzidas de glyphosate e paraquat simulando deriva na cultura do milho Effect of reduced rates of glyphosate and paraquat simulating drift in corn crop

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    P.C. Magalhães

    2001-08-01

    Full Text Available A aplicação de herbicidas, seja para a dissecação de culturas ou para o controle de plantas daninhas, vem crescendo, devido a expansão da fronteira agrícola brasileira. Esse fato aumenta os riscos de ocorrência de deriva acidental em culturas vizinhas suscetíveis. As perdas em produtividade são desconhecidas em muitas situações de ocorrência de deriva de herbicidas. O objetivo deste trabalho foi avaliar a possível toxicidade causada pela deriva de doses reduzidas de dois herbicidas (glyphosate e paraquat no período inicial de desenvolvimento da cultura do milho. Foram utilizadas cinco doses simulando deriva - 2, 4, 6, 8 e 12% da dose recomendada (1.440 g ha-1 de glyphosate e 400 g ha-1 de paraquat - sobre o cultivar de milho híbrido triplo BRS 3123. No florescimento, foram avaliados altura da planta, área foliar, peso da matéria seca, teor de clorofila e sintomas visuais de injúria. Na colheita, avaliaram-se estande final, peso de espigas, peso de 1.000 grãos e produção de grãos. A altura das plantas, a área foliar e o peso da matéria seca não foram afetados pelo efeito das derivas nos dois anos agrícolas (1996/97 e 1997/98, exceto pela área foliar, que em 1997/98 sofreu redução, sobretudo no tratamento com 12% da dose normal de glyphosate. De maneira geral, os resultados obtidos para as demais características foram semelhantes nos dois anos de condução do ensaio. O teor de clorofila nas folhas e o estande final não foram afetados pelas doses reduzidas. O grau de toxicidade, avaliado por meio de plantas injuriadas pela deriva, aos 7, 14 e 21 dias após a aplicação dos herbicidas, apresentou diferenças significativas. Os maiores danos foram observados com a maior subdose simulando deriva dos herbicidas. O peso de 1.000 grãos não foi afetado, ao passo que a produção de espigas e de grãos foi severamente prejudicada. Observou-se que a deriva simulada dos herbicidas em altas concentrações afetou o

  20. Eficiência dos dessecantes paraquat e diquat na antecipação da colheita do milho Effectiveness of the desiccants paraquat and diquat in anticipating maize harvesting

    Directory of Open Access Journals (Sweden)

    P.C. Magalhães

    2002-12-01

    Full Text Available O uso de dessecantes na cultura do milho pode trazer benefícios para os agricultores, especialmente visando a disponibilização antecipada do solo para implantação de uma nova cultura, assim como o oferecimento antecipado do produto colhido ao mercado. Dentre os dessecantes disponíveis comercialmente, os herbicidas paraquat e diquat merecem destaque. O objetivo deste trabalho foi avaliar a eficiência dos herbicidas paraquat e diquat, aplicados como dessecantes em diversos estádios de desenvolvimento da cultura de milho, sobre parâmetros produtivos e incidência de doenças nos grãos de milho. O ensaio foi conduzido na Embrapa Milho e Sorgo, Sete Lagoas, MG, utilizando-se os seguintes tratamentos: aplicação de paraquat e diquat aos 14 e 7 dias antes e aos 7 dias depois do ponto de maturação fisiológica (MF, assim como na própria MF. Ambos os produtos foram aplicados na dosagem de 400 g ha-1. O cultivar de milho utilizado foi o BRS 3101. Aos 0, 3, 6, 9, 12 e 15 dias após a aplicação dos produtos foram coletados 30 grãos de seis espigas aleatórias, para determinação da umidade dos grãos e peso da matéria seca. Na colheita foram avaliados: altura da planta e da espiga, índice de espigas, produção de grãos e espigas e sanidade dos grãos. Os produtos testados não apresentaram diferenças de eficiência para a maioria dos parâmetros avaliados, embora visualmente tenha sido constatado que o paraquat age mais rapidamente do que o diquat na secagem do tecido foliar verde. Apesar disso, quando se detectou alguma diferença entre os dois produtos químicos, o diquat foi superior ao paraquat. Com relação às épocas de aplicação dos produtos, foi constatado que a aplicação dos dessecantes aos 14 dias antes da MF resultou em redução na produção de grãos, devido à diminuição no peso da matéria seca dos grãos, apesar de ter antecipado em dois dias a MF e em quatro dias a colheita. Esse fato ficou mais bem

  1. Early Stage Blood Purification for Paraquat Poisoning: A Multicenter Retrospective Study.

    Science.gov (United States)

    Li, An; Li, Wenxiong; Hao, Fengtong; Wang, Haishi

    2016-01-01

    To evaluate the efficacy of conservative treatment vs. hemoperfusion (HP) vs. HP + continuous veno-venous hemofiltration (CVVH) for acute Paraquat (PQ) poisoning. This was a multicenter retrospective study of patients with PQ poisoning between January 2013 and June 2014. Clinical data and PQ serum levels were collected at baseline and after 24, 48, and 72 h of treatment. Seventy-five, 65, and 43 underwent conservative treatment only (conservative treatment group), conservative treatment + HP (HP group), and conservative treatment + HP + CVVH (HP + CVVH group), respectively. PQ serum levels decreased in all groups after 72 h of treatment (p treatment group. More importantly, PQ blood levels were significantly lower in the HP + CVVH group compared with the HP group at 24 h (p treatment group (p poisoning could decrease PQ blood levels, alleviate organ damage, and increase survival. © 2016 S. Karger AG, Basel.

  2. Triptolide suppresses paraquat induced idiopathic pulmonary fibrosis by inhibiting TGFB1-dependent epithelial mesenchymal transition.

    Science.gov (United States)

    Chen, Hong; Chen, Qun; Jiang, Chun-Ming; Shi, Guang-Yue; Sui, Bo-Wen; Zhang, Wei; Yang, Li-Zhen; Li, Zhu-Ying; Liu, Li; Su, Yu-Ming; Zhao, Wen-Cheng; Sun, Hong-Qiang; Li, Zhen-Zi; Fu, Zhou

    2018-03-01

    Idiopathic pulmonary fibrosis (IPF) and tumor are highly similar to abnormal cell proliferation that damages the body. This malignant cell evolution in a stressful environment closely resembles that of epithelial-mesenchymal transition (EMT). As a popular EMT-inducing factor, TGFβ plays an important role in the progression of multiple diseases. However, the drugs that target TGFB1 are limited. In this study, we found that triptolide (TPL), a Chinese medicine extract, exerts an anti-lung fibrosis effect by inhibiting the EMT of lung epithelial cells. In addition, triptolide directly binds to TGFβ and subsequently increase E-cadherin expression and decrease vimentin expression. In in vivo studies, TPL improves the survival state and inhibits lung fibrosis in mice. In summary, this study revealed the potential therapeutic effect of paraquat induced TPL in lung fibrosis by regulating TGFβ-dependent EMT progression. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Comparative studies of the mechanisms of paraquat and 1-methyl-4-phenylpyridine (MPP+) cytotoxicity

    International Nuclear Information System (INIS)

    Di Monte, D.; Sandy, M.S.; Ekstroem, G.; Smith, M.T.

    1986-01-01

    1-Methyl-4-phenylpyridine (MPP + ) is the putative toxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and is structurally similar to the herbicide paraquat (PQ ++ ). The authors have therefore compared the effects of MPP + and PQ ++ on isolated rat hepatocytes. PQ ++ generates reactive oxygen species within cells by redox cycling and its toxicity to hepatocytes was potentiated by pretreatment with 1,3-bis(2-chlorethyl)-1-nitrosourea (BCNU), an inhibitor of glutathione reductase. In BCNU-treated cells, PQ ++ caused GSH depletion, lipid peroxidation and cell death. These cytotoxic effects were prevented by the antioxidant N,N'-diphenyl-p-phenylenediamine (DPPD) and the iron-chelating agent desferrioxamine. MPP + also caused GSH depletion in BCNU-treated hepatocytes but its cytotoxicity was not markedly affected by BCNU, nor was it accompanied by significant lipid peroxidation. DPPD and desferrioxamine also failed to prevent MPP + -induced cell death

  4. A dopamine receptor contributes to paraquat-induced neurotoxicity in Drosophila

    Science.gov (United States)

    Cassar, Marlène; Issa, Abdul-Raouf; Riemensperger, Thomas; Petitgas, Céline; Rival, Thomas; Coulom, Hélène; Iché-Torres, Magali; Han, Kyung-An; Birman, Serge

    2015-01-01

    Long-term exposure to environmental oxidative stressors, like the herbicide paraquat (PQ), has been linked to the development of Parkinson's disease (PD), the most frequent neurodegenerative movement disorder. Paraquat is thus frequently used in the fruit fly Drosophila melanogaster and other animal models to study PD and the degeneration of dopaminergic neurons (DNs) that characterizes this disease. Here, we show that a D1-like dopamine (DA) receptor, DAMB, actively contributes to the fast central nervous system (CNS) failure induced by PQ in the fly. First, we found that a long-term increase in neuronal DA synthesis reduced DAMB expression and protected against PQ neurotoxicity. Secondly, a striking age-related decrease in PQ resistance in young adult flies correlated with an augmentation of DAMB expression. This aging-associated increase in oxidative stress vulnerability was not observed in a DAMB-deficient mutant. Thirdly, targeted inactivation of this receptor in glutamatergic neurons (GNs) markedly enhanced the survival of Drosophila exposed to either PQ or neurotoxic levels of DA, whereas, conversely, DAMB overexpression in these cells made the flies more vulnerable to both compounds. Fourthly, a mutation in the Drosophila ryanodine receptor (RyR), which inhibits activity-induced increase in cytosolic Ca2+, also strongly enhanced PQ resistance. Finally, we found that DAMB overexpression in specific neuronal populations arrested development of the fly and that in vivo stimulation of either DNs or GNs increased PQ susceptibility. This suggests a model for DA receptor-mediated potentiation of PQ-induced neurotoxicity. Further studies of DAMB signaling in Drosophila could have implications for better understanding DA-related neurodegenerative disorders in humans. PMID:25158689

  5. [Clinical study on the treatment of acute paraquat poisoning with sequential whole gastric and bowel irrigation].

    Science.gov (United States)

    Zhao, Bo; Dai, Jingbin; Li, Jun; Xiao, Lei; Sun, Baoquan; Liu, Naizheng; Zhang, Yanmin; Jian, Xiangdong

    2015-03-01

    To explore the clinical efficacy of early application of sequential gastrointestinal lavage in patients with acute paraquat poisoning by analyzing the clinical data of 97 patients. A total of 97 eligible patients with acute paraquat poisoning were divided into conventional treatment group (n = 48) and sequential treatment group (n = 49). The conventional treatment group received routine gastric lavage with water. Then 30 g of montmorillonite powder, 30 g of activated charcoal, and mannitol were given to remove intestinal toxins once a day for five days. The sequential treatment group received 60 g of montmorillonite powder for oral administration, followed by small-volume low-pressure manual gastric lavage with 2.5%bicarbonate liquid. Then 30 g of activated charcoal, 30 g of montmorillonite powder, and polyethylene glycol electrolyte lavage solution were given one after another for gastrointestinal lavage once a day for five days. Both groups received large doses of corticosteroids, blood perfusion, and anti-oxidation treatment. The levels of serum potassium, serum amylase (AMY) alanine aminotransferase (ALT), total bilirubin (TBIL), blood urea nitrogen (BUN), creatinine (Cr), lactate (Lac), and PaO₂of patients were determined at 1, 3, 5, 7, and 10 days. Laxative time, mortality, and survival time of dead cases were evaluated in the two groups. The incidence rates of hypokalemia (110 U/L) were significantly lower in the sequential treatment group than in the conventional treatment group (P 80 U/L), TBIL (>34.2 µmol/L), BUN (>7.2 mmol/L), and Cr (>177 µmol/L) between the two groups (P>0.05). However, the highest levels of ALT, TBIL, BUN, Cr, and Lac were significantly lower in the sequential treatment group than in the conventional treatment group (P treatment group had significantly lower incidence of PaO₂(treatment group (P poisoning.

  6. Paraquat poisoning

    Science.gov (United States)

    ... herbicide). In the past, the United States encouraged Mexico to use it to destroy marijuana plants. Later, ... Saunders; 2016:chap 75. Welker K, Thompson TM. Pesticides. In: Walls RM, Hockberger RS, Gausche-Hill M, ...

  7. Addition of immunosuppressive treatment to hemoperfusion is associated with improved survival after paraquat poisoning: a nationwide study.

    Directory of Open Access Journals (Sweden)

    Wen-Pyng Wu

    Full Text Available Paraquat poisoning associates very high mortality rate. Early treatment with hemoperfusion is strongly suggested by animal and human studies. Although the survival benefit of additional immunosuppressive treatment (IST in combination with hemoperfusion is also reported since 1971, the large-scale randomized control trials to confirm the effects of IST is difficult to be executed. Therefore, we designed this nationwide large-scale population-based retrospective cohort study to investigate the outcome of paraquat poisoning with hemoperfusion and the additional effects of IST combined with hemoperfusion. This nationwide retrospective cohort study utilized data retrieved from the National Health Insurance Research Database (NHIRD of Taiwan. A total of 1811 hospitalized patients with a diagnosis of paraquat poisoning who received hemoperfusion between 1997 and 2009 were enrolled. The mean age of all 1811 study subjects was 47.3 years. 70% was male. The overall survival rate was only 26.4%. Respiratory failure and renal failure were diagnosed in 56.2% and 36% patients. The average frequency of hemoperfusion was twice. IST was added in 42.2% patients. IST significantly increases survival rate (from 24.3% to 29.3%, P<0.001. The combined IST with methylprednisolone, cyclophosphamide and dexamethasone associates with the highest survival rate (48%, P<0.001. Moreover, patients younger than 45 years of age in the IST group had the best survival (41.0% vs. 33.7%, p<0.001. Our results support the use of IST with hemoperfusion for paraquat-poisoned patients. The best survival effect of IST is the combination of methylprednisolone, cyclophosphamide and daily dexamethasone, especially in patients with younger age.

  8. Developmental exposure to paraquat and maneb can impair cognition, learning and memory in Sprague-Dawley rats.

    Science.gov (United States)

    Li, Bai; He, Xi; Sun, Yan; Li, Baixiang

    2016-10-20

    Paraquat and maneb are identified environmental pollutants. Combined exposure to paraquat and maneb is a latent risk factor for many diseases, particularly those of the central nervous system, including Parkinson's disease and Alzheimer's disease. Hippocampus is the key structure in memory formation and babies are more sensitive to environmental stimuli than adults, so we investigated the neurotoxicity of paraquat and maneb on the hippocampi of rat pups. Female and male Sprague-Dawley rats were mated (female : male = 2 : 1) every night for a week. The gravid rats were randomly divided into three groups (one control and two experimental groups). A mixed solution of paraquat-maneb was administered twice a week by lavage at a dose of 10 or 15 mg kg(-1) bodyweight (containing 30 or 45 mg kg(-1) bodyweight maneb, respectively) from day 6 after pregnancy till ablactation. Maternal weight gain and offspring bodyweights were not affected by the drugs. However, behavioral tests showed that reaction latency and mistake frequency increased after treatment. Intuitively, we found significant changes in the hippocampal neurons in the morphological observation. Taking into account the interaction of the related genes in the cAMP-PKA-CREB pathway, we used a variety of methods to detect the gene and protein levels. Reduced expression of cAMP and related genes and proteins in the hippocampus and serum was also observed. These results indicate that PQ-MB stimulates cAMP to reduce the production of PKA, thus reducing the phosphorylation of CREB and inhibiting the activation of other elements (BDNF, C-JUN, and C-FOS). These changes lead to hippocampal damage and impaired abilities (learning, cognition, and memory). Our results demonstrate that PQ-MB induces hippocampal toxicity in the early life of rats, and they thus provide a theoretical foundation for further investigation of the bathypelagic mechanism involved and measures that can be taken to avoid PQ-MB neurotoxicity.

  9. Traditional chinese medicine Xuebijing treatment is associated with decreased mortality risk of patients with moderate paraquat poisoning.

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    Ping Gong

    Full Text Available Paraquat poisoning causes multiple organ injury and high mortality due to severe toxicity and lack of effective treatment. Xuebijing (XBJ injection, a traditional Chinese medicine preparation of five Chinese herbs (Radix Salviae Miltiorrhiae, Rhizoma Chuanxiong, Flos Carthami, Angelica Sinensis and Radix Paeoniae Rubra, has an anti-inflammatory effect and is widely used in the treatment of sepsis. This retrospective study was designed to evaluate the effects of XBJ combined with conventional therapy on mortality risk of patients with acute paraquat poisoning. Out of 68 patients, 27 were treated with conventional therapy (control group and 41 were treated with intravenous administration of XBJ (100 ml, twice a day, up to 7 days plus conventional therapy (XBJ group. Vital organ function, survival time within 28 days and adverse events during the treatment were reviewed. Results indicated that XBJ treatment significantly increased median survival time among patients ingesting 10-30 ml of paraquat (P=0.02 compared with the control group. After adjustment for covariates, XBJ treatment was associated significantly with a lower mortality risk (adjusted HR 0.242, 95% CI 0.113 to 0.516, P=0.001 compared with the control group. Additionally, compared with Day 1, on Day 3 the value of PaO2/FiO2 was significantly decreased, and the values of serum alanine aminotransferase, creatinine and troponin T were significantly increased in the control group (all P<0.05, but these values were significant improved in the XBJ group (all P<0.05. Only one patient had skin rash with itch within 30 minutes after injection and no severe adverse events were found in the XBJ group. In conclusion, XBJ treatment is associated with decreased mortality risk of patients with moderate paraquat poisoning, which may be attributed to improved function of vital organs with no severe adverse events.

  10. Traditional chinese medicine Xuebijing treatment is associated with decreased mortality risk of patients with moderate paraquat poisoning.

    Science.gov (United States)

    Gong, Ping; Lu, Zhidan; Xing, Jing; Wang, Na; Zhang, Yu

    2015-01-01

    Paraquat poisoning causes multiple organ injury and high mortality due to severe toxicity and lack of effective treatment. Xuebijing (XBJ) injection, a traditional Chinese medicine preparation of five Chinese herbs (Radix Salviae Miltiorrhiae, Rhizoma Chuanxiong, Flos Carthami, Angelica Sinensis and Radix Paeoniae Rubra), has an anti-inflammatory effect and is widely used in the treatment of sepsis. This retrospective study was designed to evaluate the effects of XBJ combined with conventional therapy on mortality risk of patients with acute paraquat poisoning. Out of 68 patients, 27 were treated with conventional therapy (control group) and 41 were treated with intravenous administration of XBJ (100 ml, twice a day, up to 7 days) plus conventional therapy (XBJ group). Vital organ function, survival time within 28 days and adverse events during the treatment were reviewed. Results indicated that XBJ treatment significantly increased median survival time among patients ingesting 10-30 ml of paraquat (P=0.02) compared with the control group. After adjustment for covariates, XBJ treatment was associated significantly with a lower mortality risk (adjusted HR 0.242, 95% CI 0.113 to 0.516, P=0.001) compared with the control group. Additionally, compared with Day 1, on Day 3 the value of PaO2/FiO2 was significantly decreased, and the values of serum alanine aminotransferase, creatinine and troponin T were significantly increased in the control group (all Ptreatment is associated with decreased mortality risk of patients with moderate paraquat poisoning, which may be attributed to improved function of vital organs with no severe adverse events.

  11. Electrochemical determination of paraquat in citric fruit based on electrodeposition of silver particles onto carbon paste electrode

    OpenAIRE

    Abdelfettah Farahi; Mounia Achak; Laila El Gaini; Moulay Abderrahim El Mhammedi; Mina Bakasse

    2015-01-01

    Carbon paste electrodes (CPEs) modified with silver particles present an interesting tool in the determination of paraquat (PQ) using square wave voltammetry. Metallic silver particle deposits have been obtained via electrochemical deposition in acidic media using cyclic voltammetry. Scanning electron microscopy and X-ray diffraction measurements show that the silver particles are deposited onto carbon surfaces in aggregate form. The response of PQ with modified electrode (Ag-CPE) related to ...

  12. Autoradiography of [14C]paraquat or [14C]diquat in frogs and mice: accumulation in neuromelanin

    International Nuclear Information System (INIS)

    Lindquist, N.G.; Larsson, B.S.; Lyden-Sokolowski, A.

    1988-01-01

    The herbicide paraquat has been suggested as a causative agent for Parkinson's disease because of its structural similarity to a metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which may induce a parkinsonism-like condition. MPTP as well as its metabolite 1-methyl-4-phenylpyridine have melanin affinity, and the parkinsonism-inducing potency of MPTP is much stronger in species with melanin in the nerve cells. Autoradiography of [ 3 H]MPTP in experimental animals has shown accumulation in melanin-containing tissues, including pigmented neurons. In the present whole body autoradiographic study accumulation and retention was seen in neuromelanin in frogs after i.p. injection of [ 14 C]paraquat or[ 14 C]diquat. By means of whole body autoradiography of [ 14 C]diquat in mice (a species with no or very limited amounts of neuromelanin) a low, relatively uniformly distributed level of radioactivity was observed in brain tissue. Accumulation of toxic chemical compounds, such as paraquat, in neuromelanin may ultimately cause lesions in the pigmented nerve cells, leading to Parkinson's disease

  13. Preparation of methacrylic acid-modified rice husk improved by an experimental design and application for paraquat adsorption

    International Nuclear Information System (INIS)

    Hsu, Shih-Tong; Chen, Lung-Chuan; Lee, Cheng-Chieh; Pan, Ting-Chung; You, Bing-Xuan; Yan, Qi-Feng

    2009-01-01

    Methacrylic acid (MAA) grafted rice husk was synthesized using graft copolymerization with Fenton's reagent as the redox initiator and applied to the adsorption of paraquat. The highest grafting percentage of 44.3% was obtained using the traditional kinetic method. However, a maximum grafting percentage of 65.3% was calculated using the central composite design. Experimental results based on the recipes predicted from the statistical analysis are consistent with theoretical calculations. A representative polymethacrylic acid-g-rice husk (PMAA-g-rice husk) copolymer was hydrolyzed to a salt type and applied to the adsorption of paraquat. The adsorption equilibrium data correlate more closely with the Langmuir isotherm than with the Freundlich equation. The maximum adsorption capacity of modified rice husk is 292.5 mg/g-adsorbent. This value exceeds those for Fuller's earth and activated carbon, which are the most common binding agents used for paraquat. The samples at various stages were characterized by solid-state 13 C NMR spectroscopy.

  14. Viral-toxin interactions and Parkinson’s disease: poly(I:C priming enhanced the neurodegenerative effects of paraquat

    Directory of Open Access Journals (Sweden)

    Bobyn Jessica

    2012-05-01

    Full Text Available Abstract Background Parkinson’s disease (PD has been linked with exposure to a variety of environmental and immunological insults (for example, infectious pathogens in which inflammatory and oxidative processes seem to be involved. In particular, epidemiological studies have found that pesticide exposure and infections may be linked with the incidence of PD. The present study sought to determine whether exposure to a viral mimic prior to exposure to pesticides would exacerbate PD-like pathology. Methods Mice received a supra-nigral infusion of 5 μg of the double-stranded RNA viral analog, polyinosinic: polycytidylic acid (poly(I:C, followed 2, 7 or 14 days later by administration of the pesticide, paraquat (nine 10 mg/kg injections over three weeks. Results As hypothesized, poly(I:C pre-treatment enhanced dopamine (DA neuron loss in the substantia nigra pars compacta elicited by subsequent paraquat treatment. The augmented neuronal loss was accompanied by robust signs of microglial activation, and by increased expression of the catalytic subunit (gp91 of the NADPH oxidase oxidative stress enzyme. However, the paraquat and poly(I:C treatments did not appreciably affect home-cage activity, striatal DA terminals, or subventricular neurogenesis. Conclusions These findings suggest that viral agents can sensitize microglial-dependent inflammatory responses, thereby rendering nigral DA neurons vulnerable to further environmental toxin exposure.

  15. Autoradiography of ( sup 14 C)paraquat or ( sup 14 C)diquat in frogs and mice: accumulation in neuromelanin

    Energy Technology Data Exchange (ETDEWEB)

    Lindquist, N G; Larsson, B S; Lyden-Sokolowski, A [Uppsala Univ., Biomedical Center, (Sweden). Dept. of Toxicology

    1988-10-31

    The herbicide paraquat has been suggested as a causative agent for Parkinson's disease because of its structural similarity to a metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), which may induce a parkinsonism-like condition. MPTP as well as its metabolite 1-methyl-4-phenylpyridine have melanin affinity, and the parkinsonism-inducing potency of MPTP is much stronger in species with melanin in the nerve cells. Autoradiography of ({sup 3}H)MPTP in experimental animals has shown accumulation in melanin-containing tissues, including pigmented neurons. In the present whole body autoradiographic study accumulation and retention was seen in neuromelanin in frogs after i.p. injection of ({sup 14}C)paraquat or({sup 14}C)diquat. By means of whole body autoradiography of ({sup 14}C)diquat in mice (a species with no or very limited amounts of neuromelanin) a low, relatively uniformly distributed level of radioactivity was observed in brain tissue. Accumulation of toxic chemical compounds, such as paraquat, in neuromelanin may ultimately cause lesions in the pigmented nerve cells, leading to Parkinson's disease.

  16. Addition of immunosuppressive treatment to hemoperfusion is associated with improved survival after paraquat poisoning: a nationwide study.

    Science.gov (United States)

    Wu, Wen-Pyng; Lai, Ming-Nan; Lin, Ching-Heng; Li, Yu-Fen; Lin, Ching-Yuang; Wu, Ming-Ju

    2014-01-01

    Paraquat poisoning associates very high mortality rate. Early treatment with hemoperfusion is strongly suggested by animal and human studies. Although the survival benefit of additional immunosuppressive treatment (IST) in combination with hemoperfusion is also reported since 1971, the large-scale randomized control trials to confirm the effects of IST is difficult to be executed. Therefore, we designed this nationwide large-scale population-based retrospective cohort study to investigate the outcome of paraquat poisoning with hemoperfusion and the additional effects of IST combined with hemoperfusion. This nationwide retrospective cohort study utilized data retrieved from the National Health Insurance Research Database (NHIRD) of Taiwan. A total of 1811 hospitalized patients with a diagnosis of paraquat poisoning who received hemoperfusion between 1997 and 2009 were enrolled. The mean age of all 1811 study subjects was 47.3 years. 70% was male. The overall survival rate was only 26.4%. Respiratory failure and renal failure were diagnosed in 56.2% and 36% patients. The average frequency of hemoperfusion was twice. IST was added in 42.2% patients. IST significantly increases survival rate (from 24.3% to 29.3%, Ppoisoned patients. The best survival effect of IST is the combination of methylprednisolone, cyclophosphamide and daily dexamethasone, especially in patients with younger age.

  17. Preparation of methacrylic acid-modified rice husk improved by an experimental design and application for paraquat adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Shih-Tong, E-mail: shihtong@mail.ksu.edu.tw [Department of Polymer Materials, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City, Tainan Hsien, Taiwan (China); Chen, Lung-Chuan, E-mail: lcchen@mail.ksu.edu.tw [Department of Polymer Materials, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City, Tainan Hsien, Taiwan (China); Lee, Cheng-Chieh, E-mail: etmediagoing@yahoo.com.tw [Department of Environmental Engineering, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City 710, Tainan Hsien, Taiwan (China); Pan, Ting-Chung, E-mail: tcpan@mail.ksu.edutw [Department of Environmental Engineering, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City 710, Tainan Hsien, Taiwan (China); You, Bing-Xuan, E-mail: kp2681@yahoo.com.tw [Department of Polymer Materials, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City, Tainan Hsien, Taiwan (China); Yan, Qi-Feng, E-mail: rsrs0938@yahoo.com.tw [Department of Polymer Materials, Kun Shan University, No. 949 Da-Wan Rd., Yung-Kang City, Tainan Hsien, Taiwan (China)

    2009-11-15

    Methacrylic acid (MAA) grafted rice husk was synthesized using graft copolymerization with Fenton's reagent as the redox initiator and applied to the adsorption of paraquat. The highest grafting percentage of 44.3% was obtained using the traditional kinetic method. However, a maximum grafting percentage of 65.3% was calculated using the central composite design. Experimental results based on the recipes predicted from the statistical analysis are consistent with theoretical calculations. A representative polymethacrylic acid-g-rice husk (PMAA-g-rice husk) copolymer was hydrolyzed to a salt type and applied to the adsorption of paraquat. The adsorption equilibrium data correlate more closely with the Langmuir isotherm than with the Freundlich equation. The maximum adsorption capacity of modified rice husk is 292.5 mg/g-adsorbent. This value exceeds those for Fuller's earth and activated carbon, which are the most common binding agents used for paraquat. The samples at various stages were characterized by solid-state {sup 13}C NMR spectroscopy.

  18. Preparation of methacrylic acid-modified rice husk improved by an experimental design and application for paraquat adsorption.

    Science.gov (United States)

    Hsu, Shih-Tong; Chen, Lung-Chuan; Lee, Cheng-Chieh; Pan, Ting-Chung; You, Bing-Xuan; Yan, Qi-Feng

    2009-11-15

    Methacrylic acid (MAA) grafted rice husk was synthesized using graft copolymerization with Fenton's reagent as the redox initiator and applied to the adsorption of paraquat. The highest grafting percentage of 44.3% was obtained using the traditional kinetic method. However, a maximum grafting percentage of 65.3% was calculated using the central composite design. Experimental results based on the recipes predicted from the statistical analysis are consistent with theoretical calculations. A representative polymethacrylic acid-g-rice husk (PMAA-g-rice husk) copolymer was hydrolyzed to a salt type and applied to the adsorption of paraquat. The adsorption equilibrium data correlate more closely with the Langmuir isotherm than with the Freundlich equation. The maximum adsorption capacity of modified rice husk is 292.5mg/g-adsorbent. This value exceeds those for Fuller's earth and activated carbon, which are the most common binding agents used for paraquat. The samples at various stages were characterized by solid-state (13)C NMR spectroscopy.

  19. Paraquat induces oxidative stress, neuronal loss in substantia nigra region and Parkinsonism in adult rats: Neuroprotection and amelioration of symptoms by water-soluble formulation of Coenzyme Q10

    Directory of Open Access Journals (Sweden)

    Sridhar TS

    2009-07-01

    Full Text Available Abstract Background Parkinson's disease, for which currently there is no cure, develops as a result of progressive loss of dopamine neurons in the brain; thus, identification of any potential therapeutic intervention for disease management is of a great importance. Results Here we report that prophylactic application of water-soluble formulation of coenzyme Q10 could effectively offset the effects of environmental neurotoxin paraquat, believed to be a contributing factor in the development of familial PD. In this study we utilized a model of paraquat-induced dopaminergic neurodegeneration in adult rats that received three weekly intra-peritoneal injections of the herbicide paraquat. Histological and biochemical analyses of rat brains revealed increased levels of oxidative stress markers and a loss of approximately 65% of dopamine neurons in the substantia nigra region. The paraquat-exposed rats also displayed impaired balancing skills on a slowly rotating drum (rotorod evidenced by their reduced spontaneity in gait performance. In contrast, paraquat exposed rats receiving a water-soluble formulation of coenzyme Q10 in their drinking water prior to and during the paraquat treatment neither developed neurodegeneration nor reduced rotorod performance and were indistinguishable from the control paraquat-untreated rats. Conclusion Our data confirmed that paraquat-induced neurotoxicity represents a convenient rat model of Parkinsonian neurodegeneration suitable for mechanistic and neuroprotective studies. This is the first preclinical evaluation of a water-soluble coenzyme Q10 formulation showing the evidence of prophylactic neuroprotection at clinically relevant doses.

  20. The Protective Effect of Minocycline in a Paraquat-Induced Parkinson's Disease Model in Drosophila is Modified in Altered Genetic Backgrounds

    Directory of Open Access Journals (Sweden)

    Arati A. Inamdar

    2012-01-01

    Full Text Available Epidemiological studies link the herbicide paraquat to increased incidence of Parkinson's disease (PD. We previously reported that Drosophila exposed to paraquat recapitulate PD symptoms, including region-specific degeneration of dopaminergic neurons. Minocycline, a tetracycline derivative, exerts ameliorative effects in neurodegenerative disease models, including Drosophila. We investigated whether our environmental toxin-based PD model could contribute to an understanding of cellular and genetic mechanisms of minocycline action and whether we could assess potential interference with these drug effects in altered genetic backgrounds. Cofeeding of minocycline with paraquat prolonged survival, rescued mobility defects, blocked generation of reactive oxygen species, and extended dopaminergic neuron survival, as has been reported previously for a genetic model of PD in Drosophila. We then extended this study to identify potential interactions of minocycline with genes regulating dopamine homeostasis that might modify protection against paraquat and found that deficits in GTP cyclohydrolase adversely affect minocycline rescue. We further performed genetic studies to identify signaling pathways that are necessary for minocycline protection against paraquat toxicity and found that mutations in the Drosophila genes that encode c-Jun N-terminal kinase (JNK and Akt/Protein kinase B block minocycline rescue.

  1. The roles of anion and solvent transport during the redox switching process at a poly(butyl viologen) film studied by an EQCM

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Chih-Yu.; Liao, Chun-Hao [Department of Chemical Engineering, National Taiwan University, Taipei 10617 (China); Ho, Kuo-Chuan [Department of Chemical Engineering, National Taiwan University, Taipei 10617 (China); Institute of Polymer Science and Engineering, National Taiwan University, Taipei 10617 (China)

    2008-02-15

    In this study, three electrolytes (KCl, LiCl, and KNO{sub 3}, each at 0.5 M in aqueous solution) were chosen to study the ion and solvent effect on the redox performance of poly(butyl viologen) (PBV) thin-films between its di-cation and radical-cation state, which is referred as its first redox couple. Before considering the role of ionic transport on the redox process, the exchange between ferrocyanide and anion should be completed. Since the deposition solution of PBV contains potassium ferrocyanide, the residual ferrocyanides inside the films would be exchanged by smaller anions from the bulk solution during the redox reaction of PBV. From cyclic voltammetry (CV) and electrochemical quartz crystal microbalance (EQCM) results, the exchange was almost complete around 50 cycles when scanning the potential within its first redox range. After completion of the exchange process, the transfer would reach a steady state. At 50 cycles, the EQCM results suggested that the transport involves anions and water only for both being extracted upon reduction and being inserted upon oxidation. Therefore, we could obtain the molar fluxes of Cl{sup -}, NO{sub 3}{sup -}, and water. Besides, the average numbers of accompanying water were calculated to be about 24.8 per Cl{sup -} and 14.2 per NO{sub 3}{sup -} upon redox switching process. The instantaneous water to anion molar ratios at any potential were also obtained for Cl{sup -} and NO{sub 3}{sup -}. (author)

  2. Charge-Transfer Supra-Amphiphiles Built by Water-Soluble Tetrathiafulvalenes and Viologen-Containing Amphiphiles: Supramolecular Nanoassemblies with Modifiable Dimensions.

    Science.gov (United States)

    Lv, Zhong-Peng; Chen, Bin; Wang, Hai-Ying; Wu, Yue; Zuo, Jing-Lin

    2015-08-05

    In this study, multidimensional nanoassemblies with various morphologies such as nanosheets, nanorods, and nanofibers are developed via charge-transfer interaction and supra-amphiphile self-assembling in aqueous phase. The charge-transfer interactions between tetrathiafulvalene derivatives (TTFs) and methyl viologen derivatives (MVs) have been confirmed by the characteristic charger-transfer absorption. (1) H NMR and electrospray ionizsation mass spectrometry (ESI-MS) analyses also indicate supra-amphiphiles are formed by the combination of TTFs and MVs head group through charge-transfer interaction and Coulombic force. X-ray single crystal structural studies, transmission electron microscopy (TEM), and scanning electron microscopy (SEM) reveal that both linkage pattern of TTFs in hydrophilic part and alkane chain structure in hydrophobic part have significant influence on nanoassemblies morphology and microstructure. Moreover, gold nanoparticles (AuNPs) are introduced in the above supramolecular nanoassemblies to construct a supra-amphiphile-driven organic-AuNPs assembly system. AuNPs could be assembled into 1D-3D structures by adding different amount of MVs. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Neurobehavioral effects of concurrent exposure to cesium-137 and paraquat during neonatal development in mice

    International Nuclear Information System (INIS)

    Heredia, Luis; Bellés, Montserrat; Llovet, Maria Isabel; Domingo, Jose L.; Linares, Victoria

    2015-01-01

    As a result of nuclear power plants accidents such as Chernobyl or Fukushima, some people were exposed to external and internal ionizing radiation (IR). Human brain is highly sensitive to IR during fetal and postnatal period when the molecular processes are not completely finished. Various studies have shown that exposure to low doses of IR causes a higher incidence of cognitive impairment. On the other hand, in industrialized countries, people are daily exposed to a number of toxicant pollutants. Exposure to environmental chemicals, such as paraquat (PQ), may potentiate the toxic effects induced by radiation on brain development. In this study, we evaluated the cognitive effects of concomitant exposure to low doses of internal radiation ( 137 Cs) and PQ during neonatal brain development. At the postnatal day 10 (PND10), two groups of mice (C57BL/6J) were exposed to 137 Cs (4000 and 8000 Bq/kg) and/or PQ (7 mg/kg). To investigate the spontaneous behavior, learning, memory capacities and anxiety, behavioral tests were conducted in the offspring at two months of age. The results showed that cognitive functions were not significantly affected when 137 Cs or PQ were administered alone. However, alterations in the working memory and anxiety were detected in mice exposed to 137 Cs combined with PQ

  4. Neurobehavioral effects of concurrent exposure to cesium-137 and paraquat during neonatal development in mice.

    Science.gov (United States)

    Heredia, Luis; Bellés, Montserrat; Llovet, Maria Isabel; Domingo, Jose L; Linares, Victoria

    2015-03-02

    As a result of nuclear power plants accidents such as Chernobyl or Fukushima, some people were exposed to external and internal ionizing radiation (IR). Human brain is highly sensitive to IR during fetal and postnatal period when the molecular processes are not completely finished. Various studies have shown that exposure to low doses of IR causes a higher incidence of cognitive impairment. On the other hand, in industrialized countries, people are daily exposed to a number of toxicant pollutants. Exposure to environmental chemicals, such as paraquat (PQ), may potentiate the toxic effects induced by radiation on brain development. In this study, we evaluated the cognitive effects of concomitant exposure to low doses of internal radiation ((137)Cs) and PQ during neonatal brain development. At the postnatal day 10 (PND10), two groups of mice (C57BL/6J) were exposed to (137)Cs (4000 and 8000 Bq/kg) and/or PQ (7 mg/kg). To investigate the spontaneous behavior, learning, memory capacities and anxiety, behavioral tests were conducted in the offspring at two months of age. The results showed that cognitive functions were not significantly affected when (137)Cs or PQ were administered alone. However, alterations in the working memory and anxiety were detected in mice exposed to (137)Cs combined with PQ. Copyright © 2015. Published by Elsevier Ireland Ltd.

  5. Tualang Honey Protects the Rat Midbrain and Lung against Repeated Paraquat Exposure

    Directory of Open Access Journals (Sweden)

    Suk Peng Tang

    2017-01-01

    Full Text Available Paraquat (PQ is a dopaminergic neurotoxin and a well-known pneumotoxicant that exerts its toxic effect via oxidative stress-mediated cellular injuries. This study investigated the protective effects of Tualang honey against PQ-induced toxicity in the midbrain and lungs of rats. The rats were orally treated with distilled water (2 mL/kg/day, Tualang honey (1.0 g/kg/day, or ubiquinol (0.2 g/kg/day throughout the experimental period. Two weeks after the respective treatments, the rats were injected intraperitoneally with saline (1 mL/kg/week or PQ (10 mg/kg/week once per week for four consecutive weeks. After four weekly exposures to PQ, the glutathione peroxidase activity and the number of tyrosine-hydroxylase immunopositive neurons in the midbrain were significantly decreased in animals from group PQ (p<0.05. The lungs of animals from group PQ showed significantly decreased activity of superoxide dismutase and glutathione-S-transferase. Treatment with Tualang honey ameliorated the toxic effects observed in the midbrain and lungs. The beneficial effects of Tualang honey were comparable to those of ubiquinol, which was used as a positive control. These findings suggest that treatment with Tualang honey may protect against PQ-induced toxicity in the rat midbrain and lung.

  6. Tualang Honey Protects the Rat Midbrain and Lung against Repeated Paraquat Exposure.

    Science.gov (United States)

    Tang, Suk Peng; Kuttulebbai Nainamohamed Salam, Sirajudeen; Jaafar, Hasnan; Gan, Siew Hua; Muzaimi, Mustapha; Sulaiman, Siti Amrah

    2017-01-01

    Paraquat (PQ) is a dopaminergic neurotoxin and a well-known pneumotoxicant that exerts its toxic effect via oxidative stress-mediated cellular injuries. This study investigated the protective effects of Tualang honey against PQ-induced toxicity in the midbrain and lungs of rats. The rats were orally treated with distilled water (2 mL/kg/day), Tualang honey (1.0 g/kg/day), or ubiquinol (0.2 g/kg/day) throughout the experimental period. Two weeks after the respective treatments, the rats were injected intraperitoneally with saline (1 mL/kg/week) or PQ (10 mg/kg/week) once per week for four consecutive weeks. After four weekly exposures to PQ, the glutathione peroxidase activity and the number of tyrosine-hydroxylase immunopositive neurons in the midbrain were significantly decreased in animals from group PQ ( p honey ameliorated the toxic effects observed in the midbrain and lungs. The beneficial effects of Tualang honey were comparable to those of ubiquinol, which was used as a positive control. These findings suggest that treatment with Tualang honey may protect against PQ-induced toxicity in the rat midbrain and lung.

  7. Tualang Honey Protects the Rat Midbrain and Lung against Repeated Paraquat Exposure

    Science.gov (United States)

    Sulaiman, Siti Amrah

    2017-01-01

    Paraquat (PQ) is a dopaminergic neurotoxin and a well-known pneumotoxicant that exerts its toxic effect via oxidative stress-mediated cellular injuries. This study investigated the protective effects of Tualang honey against PQ-induced toxicity in the midbrain and lungs of rats. The rats were orally treated with distilled water (2 mL/kg/day), Tualang honey (1.0 g/kg/day), or ubiquinol (0.2 g/kg/day) throughout the experimental period. Two weeks after the respective treatments, the rats were injected intraperitoneally with saline (1 mL/kg/week) or PQ (10 mg/kg/week) once per week for four consecutive weeks. After four weekly exposures to PQ, the glutathione peroxidase activity and the number of tyrosine-hydroxylase immunopositive neurons in the midbrain were significantly decreased in animals from group PQ (p honey ameliorated the toxic effects observed in the midbrain and lungs. The beneficial effects of Tualang honey were comparable to those of ubiquinol, which was used as a positive control. These findings suggest that treatment with Tualang honey may protect against PQ-induced toxicity in the rat midbrain and lung. PMID:28127418

  8. Determination of paraquat in water samples using a sensitive fluorescent probe titration method.

    Science.gov (United States)

    Yao, Feihu; Liu, Hailong; Wang, Guangquan; Du, Liming; Yin, Xiaofen; Fu, Yunlong

    2013-06-01

    Paraquat (PQ), a nonselective herbicide, is non-fluorescent in aqueous solutions. Thus, its determination through direct fluorescent methods is not feasible. The supramolecular inclusion interaction of PQ with cucurbit[7]uril was studied by a fluorescent probe titration method. Significant quenching of the fluorescence intensity of the cucurbit[7]uril-coptisine fluorescent probe was observed with the addition of PQ. A new fluorescent probe titration method with high selectivity and sensitivity at the ng/mL level was developed to determine PQ in aqueous solutions with good precision and accuracy based on the significant quenching of the supramolecular complex fluorescence intensity. The proposed method was successfully used in the determination of PQ in lake water, tap water, well water, and ditch water in an agricultural area, with recoveries of 96.73% to 105.77%. The fluorescence quenching values (deltaF) showed a good linear relationship with PQ concentrations from 1.0 x 10(-8) to 1.2 x 10(-5) mol/L with a detection limit of 3.35 x 10(-9) mol/L. In addition, the interaction models of the supramolecular complexes formed between the host and the guest were established using theoretical calculations. The interaction mechanism between the cucurbit[7]uril and PQ was confirmed by 1H NMR spectroscopy.

  9. Maneb and Paraquat-Mediated Neurotoxicity: Involvement of Peroxiredoxin/Thioredoxin System

    Science.gov (United States)

    Roede, James R.; Hansen, Jason M.; Go, Young-Mi; Jones, Dean P.

    2011-01-01

    Epidemiological and in vivo studies have demonstrated that exposure to the pesticides paraquat (PQ) and maneb (MB) increase the risk of developing Parkinson’s disease (PD) and cause dopaminergic cell loss, respectively. PQ is a well-recognized cause of oxidative toxicity; therefore, the purpose of this study was to determine if MB potentiates oxidative stress caused by PQ, thus providing a mechanism for enhanced neurotoxicity by the combination. The results show that PQ alone at a moderately toxic dose (20–30% cell death in 24 h) caused increased reactive oxygen species (ROS) generation, oxidation of mitochondrial thioredoxin-2 and peroxiredoxin-3, lesser oxidation of cytoplasmic thioredoxin-1 and peroxiredoxin-1, and no oxidation of cellular GSH/GSSG. In contrast, MB alone at a similar toxic dose resulted in no ROS generation, no oxidation of thioredoxin and peroxiredoxin, and an increase in cellular GSH after 24 h. Together, MB increased GSH and inhibited ROS production and thioredoxin/peroxiredoxin oxidation observed with PQ alone, yet resulted in more extensive (> 50%) cell death. MB treatment resulted in increased abundance of nuclear Nrf2 and mRNA for phase II enzymes under the control of Nrf2, indicating activation of cell protective responses. The results show that MB potentiation of PQ neurotoxicity does not occur by enhancing oxidative stress and suggests that increased toxicity occurs by a combination of divergent mechanisms, perhaps involving alkylation by MB and oxidation by PQ. PMID:21402726

  10. Metabolomic Analysis Provides Insights on Paraquat-Induced Parkinson-Like Symptoms in Drosophila melanogaster.

    Science.gov (United States)

    Shukla, Arvind Kumar; Ratnasekhar, Ch; Pragya, Prakash; Chaouhan, Hitesh Singh; Patel, Devendra Kumar; Chowdhuri, Debapratim Kar; Mudiam, Mohana Krishna Reddy

    2016-01-01

    Paraquat (PQ) exposure causes degeneration of the dopaminergic neurons in an exposed organism while altered metabolism has a role in various neurodegenerative disorders. Therefore, the study presented here was conceived to depict the role of altered metabolism in PQ-induced Parkinson-like symptoms and to explore Drosophila as a potential model organism for such studies. Metabolic profile was generated in control and in flies that were fed PQ (5, 10, and 20 mM) in the diet for 12 and 24 h concurrent with assessment of indices of oxidative stress, dopaminergic neurodegeneration, and behavioral alteration. PQ was found to significantly alter 24 metabolites belonging to different biological pathways along with significant alterations in the above indices. In addition, PQ attenuated brain dopamine content in the exposed organism. The study demonstrates that PQ-induced alteration in the metabolites leads to oxidative stress and neurodegeneration in the exposed organism along with movement disorder, a phenotype typical of Parkinson-like symptoms. The study is relevant in the context of Drosophila and humans because similar alteration in the metabolic pathways has been observed in both PQ-exposed Drosophila and in postmortem samples of patients with Parkinsonism. Furthermore, this study provides advocacy towards the applicability of Drosophila as an alternate model organism for pre-screening of environmental chemicals for their neurodegenerative potential with altered metabolism.

  11. Toxicidad in vitro de los herbicidas atrazina y paraquat sobre el crecimiento vegetativo y la esporulación de hongos saprobios del suelo

    OpenAIRE

    CHAN CUPUL, Wilberth; HEREDIA ABARCA, Gabriela; RODRÍGUEZ VÁZQUEZ, Refugio; ARIAS MOTA, Rosa María

    2014-01-01

    El objetivo de este estudio fue evaluar la toxicidad in vitro de los herbicidas atrazina y paraquat sobre el crecimiento vegetativo y la esporulación de hongos saprobios del suelo. Se realizaron bioensayos dosis-respuesta en trece especies con cuatro concentraciones de atrazina (468, 937, 1875 y 3750 mg/L) y paraquat (93, 187, 375 y 750 mg/L). Los hongos fueron inoculados con 2 μL de una suspensión de 1.0 x 10(6) esporas/mL en cajas de Petri con agar papa dextrosa (APD) adicionado con atrazin...

  12. Paraquat and maneb co-exposure induces noradrenergic locus coeruleus neurodegeneration through NADPH oxidase-mediated microglial activation

    International Nuclear Information System (INIS)

    Hou, Liyan; Zhang, Cong; Wang, Ke; Liu, Xiaofang; Wang, Hongwei; Che, Yuning; Sun, Fuqiang; Zhou, Xueying; Zhao, Xiulan; Wang, Qingshan

    2017-01-01

    Highlights: • Microglial activation induced by paraquat and maneb precedes noradrenergic neurodegeneration in locus coeruleus. • NADPH oxidase activation contributes to microglia-mediated neuroinflammation and related noradrenergic neurodegeneration. • Inhibition of NADPH oxidase by apocynin protects noradrenergic neurons against paraquat and maneb-induced toxicity. - Abstract: Co-exposure to paraquat (PQ) and maneb (Mb) has been shown to increase the risk of Parkinson’s disease (PD) and dopaminergic (DA) neurodegeneration in the substantia nigra pars compacta (SNpc) is observed in PQ and Mb-treated experimental animals. The loss of noradrenergic locus coeruleus (LC/NE) neurons in brainstem is a common feature shared by multiple neurodegenerative diseases, including PD. However, whether PQ and Mb is able to damage LC/NE neurons remains undefined. In this study, mice treated with combined PQ and Mb displayed progressive LC/NE neurodegeneration. Time course studies revealed that the activation of microglia preceded LC/NE neurodegeneration. Mechanistically, the activation of NADPH oxidase contributed to microglial activation and subsequent LC/NE neurodegeneration. We found that PQ and Mb co-exposure induced activation of NADPH oxidase as shown by increased superoxide production and membrane translocation of p47 phox , a cytosolic subunit of NADPH oxidase. Inhibition of NADPH oxidase by apocynin, a widely used NADPH oxidase inhibitor, suppressed microglial activation and gene expressions of proinflammatory factors. Furthermore, reduced activation of nuclear factor-κB (NF-κB) pathway was observed in apocynin-treated mice. More importantly, inhibition of NADPH oxidase by apocynin afforded LC/NE neuroprotection against PQ and Mb-induced neurotoxicity. Thus, our findings revealed the critical role NADPH oxidase-mediated microglial activation in driving LC/NE neurodegeneration induced by PQ and Mb, providing new insights into the pathogenesis of environmental

  13. Efeito tóxico dos praguicidas maneb e paraquat sobre a atividade da enzima antioxidante catalase em ratos

    Directory of Open Access Journals (Sweden)

    M. D. Arbo

    2009-01-01

    Full Text Available

    Os radicais livres estão envolvidos em um grande número de enfermidades do ser humano. O cérebro tem níveis baixos de enzimas antioxidantes e um conteúdo lípidico elevado, tornando-se muito susceptível ao ataque de espécies reativas de oxigênio. Neste trabalho avaliou- se a lipoperoxidação em hipocampo e a atividade da enzima catalase em estriado e hipocampo de ratos tratados com o fungicida maneb (30 mg/kg e o herbicida paraquat (10 mg/kg. Não houve alteração na lipoperoxidação nem na atividade enzimática no hipocampo dos animais tratados com ambos os praguicidas, porém foi observada uma inibição da catalase no estriado dos ratos tratados com maneb e com paraquat. Com estes resultados pode-se sugerir, de forma preliminar, uma ação tóxica maior sobre centros dopaminérgicos. Estudos sobre a toxicidade destes compostos são essenciais na compreensão do papel destes praguicidas e dos radicais livres na etiologia das doenças. Palavras-chave: catalase; paraquat; maneb; estriado; hipocampo; radicais livres.

  14. P-glycoprotein induction in Caco-2 cells by newly synthetized thioxanthones prevents paraquat cytotoxicity.

    Science.gov (United States)

    Silva, Renata; Palmeira, Andreia; Carmo, Helena; Barbosa, Daniel José; Gameiro, Mariline; Gomes, Ana; Paiva, Ana Mafalda; Sousa, Emília; Pinto, Madalena; Bastos, Maria de Lourdes; Remião, Fernando

    2015-10-01

    The induction of P-glycoprotein (P-gp), an ATP-dependent efflux pump, has been proposed as a strategy against the toxicity induced by P-gp substrates such as the herbicide paraquat (PQ). The aim of this study was to screen five newly synthetized thioxanthonic derivatives, a group known to interact with P-gp, as potential inducers of the pump's expression and/or activity and to evaluate whether they would afford protection against PQ-induced toxicity in Caco-2 cells. All five thioxanthones (20 µM) caused a significant increase in both P-gp expression and activity as evaluated by flow cytometry using the UIC2 antibody and rhodamine 123, respectively. Additionally, it was demonstrated that the tested compounds, when present only during the efflux of rhodamine 123, rapidly induced an activation of P-gp. The tested compounds also increased P-gp ATPase activity in MDR1-Sf9 membrane vesicles, indicating that all derivatives acted as P-gp substrates. PQ cytotoxicity was significantly reduced in the presence of four thioxanthone derivatives, and this protective effect was reversed upon incubation with a specific P-gp inhibitor. In silico studies showed that all the tested thioxanthones fitted onto a previously described three-feature P-gp induction pharmacophore. Moreover, in silico interactions between thioxanthones and P-gp in the presence of PQ suggested that a co-transport mechanism may be operating. Based on the in vitro activation results, a pharmacophore model for P-gp activation was built, which will be of further use in the screening for new P-gp activators. In conclusion, the study demonstrated the potential of the tested thioxanthonic compounds in protecting against toxic effects induced by P-gp substrates through P-gp induction and activation.

  15. Adiponectin attenuates lung fibroblasts activation and pulmonary fibrosis induced by paraquat.

    Science.gov (United States)

    Yao, Rong; Cao, Yu; He, Ya-rong; Lau, Wayne Bond; Zeng, Zhi; Liang, Zong-an

    2015-01-01

    Pulmonary fibrosis is one of the most common complications of paraquat (PQ) poisoning, which demands for more effective therapies. Accumulating evidence suggests adiponectin (APN) may be a promising therapy against fibrotic diseases. In the current study, we determine whether the exogenous globular APN isoform protects against pulmonary fibrosis in PQ-treated mice and human lung fibroblasts, and dissect the responsible underlying mechanisms. BALB/C mice were divided into control group, PQ group, PQ + low-dose APN group, and PQ + high-dose APN group. Mice were sacrificed 3, 7, 14, and 21 days after PQ treatment. We compared pulmonary histopathological changes among different groups on the basis of fibrosis scores, TGF-β1, CTGF and α-SMA pulmonary content via Western blot and real-time quantitative fluorescence-PCR (RT-PCR). Blood levels of MMP-9 and TIMP-1 were determined by ELISA. Human lung fibroblasts WI-38 were divided into control group, PQ group, APN group, and APN receptor (AdipoR) 1 small-interfering RNA (siRNA) group. Fibroblasts were collected 24, 48, and 72 hours after PQ exposure for assay. Cell viability and apoptosis were determined via Kit-8 (CCK-8) and fluorescein Annexin V-FITC/PI double labeling. The protein and mRNA expression level of collagen type III, AdipoR1, and AdipoR2 were measured by Western blot and RT-PCR. APN treatment significantly decreased the lung fibrosis scores, protein and mRNA expression of pulmonary TGF-β1, CTGF and α-SMA content, and blood MMP-9 and TIMP-1 in a dose-dependent manner (ppulmonary fibrosis in a dose-dependent manner, via suppression of lung fibroblast activation. Functional AdipoR1 are expressed by human WI-38 lung fibroblasts, suggesting potential future clinical applicability of APN against pulmonary fibrosis.

  16. Mineral uptake by taro (colocasla esculenta) in swamp agroecosystem following gramoxone paraquat herbicide spraying

    International Nuclear Information System (INIS)

    Nashriyah Mat; Mazleha Maskin; Abdul Khalik Wood

    2006-01-01

    Mineral elemental uptake by Colocasia esculenta growing in swamp agroecosystem was studied following 14, 18 or 28 months of field spraying (MAT, months after treatment) with herbicide Gramoxone paraquat. In overall, Al (68226.67 ± 24066.56 μ/g dw) was the major element in riverine alluvial swamp soil, followed by micronutrient Fe (22280.00 ± 6328.87 μ/g dw). Concentration of macronutrient K (20733.33 ± 7371.82, μ/g dw) was the highest in swamp taro leaf followed by macronutrient Ca (7050.00 ± 3767.26 μ/g dw). In overall, the order of importance of the average mineral concentration in swamp taro leaf was K > Ca > Mn > Al > Na > Fe > Zn > Br > Co. However at 14 MAT, the order of importance of mineral content concentration in swamp taro leaf was K > Ca > Al > Na > Mn > Fe > Zn > Br > Co. At 18 MAT, the order of importance of mineral content concentration in swamp taro leaf was K > Ca > Mn > Al > Fe > Na > Zn > Br > Co. At 28 AMT, the order of importance of mineral content concentration in swamp taro leaf was K > Ca > Mn > Fe > Al > Zn > Na > Br > Co. In overall, the average order of importance of mineral elemental uptake or the soil plant transfer coefficient was Mn > K > Na > Zn > Co > Fe > Al; similar with the order at 28 MAT However, at 14 MAT the order of importance of the soil plant transfer coefficient was different at Mn > K > Na > Co > Zn > Al > Fe. (Author)

  17. Medical Management and Outcome of Paraquat Poisoning in Ahvaz, Iran: A Hospital-Based Study

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    Ali Hasan Rahmani

    2015-06-01

    Full Text Available Background: Paraquat (PQ poisoning is highly fatal; and therefore, clinicians should be familiar with prompt approach to and poor prognostic features of this type of poisoning. Hence, in this study, clinical profile, management and outcome of a series of patients with PQ poisoning are presented. Methods: A retrospective review of medical records of patients poisoned with PQ who were treated at Clinical Toxicology Department of Razi Hospital in Ahwaz, Iran during 2005 to 2008 was performed.  Results: Forty-two patients (66.7% men were studied. Majority of them (83.3% were between 15-29 years of age. Most of PQ poisonings occurred following suicidal ideation (39 patients; 92.9%. The most common on-admission clinical findings of the patients were vomiting (69% and respiratory distress (47.6%. Activated charcoal was given to 35 patients (83.3%. N-acetyl cysteine (100 mg/kg IV stat, vitamin E (100 IU daily IV and vitamin C (500 mg daily IV were given to all patients. Exploratory endoscopy for plausible mucosal ulcers was carried out for 23 patients (54.8%. Pantoprazole (40 mg twice daily was given to all patients and for 7 patients with upper gastrointestinal (GI irritation and GI bleeding, higher doses of pantoprazole (8 mg/hour was administered. All patients received pulse therapy with methyl prednisolone (1g daily for three days and cyclophosphamide (15 mg/kg daily for two days. Twenty patients died. Comparing death and survival, death was significantly higher in patients with respiratory distress (100 vs. 0.0 %, P < 0.001, renal dysfunction (85.0 vs. 9.1 %, P < 0.001 and hepatic dysfunction (75.0 vs. 4.5 %, P < 0.001. Conclusion: PQ poisoning creates a life-threatening clinical situation, which requires quick and proper treatment. Based on this research, mortality rate is greater in the presence of renal, hepatic and respiratory dysfunction.

  18. A narrow quantitative trait locus in C. elegans coordinately affects longevity, thermotolerance, and resistance to paraquat

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    Anthony eVertino

    2011-09-01

    Full Text Available By linkage mapping of quantitative trait loci, we previously identified at least 11 natural genetic variants that significantly modulate C. elegans lifespan, many of which would have eluded discovery by knockdown or mutation screens. A region on chromosome IV between markers stP13 and stP35 had striking effects on longevity in three interstrain crosses (each P < 1E–9. In order to define the limits of that interval, we have now constructed two independent lines by marker-based selection during 20 backcross generations, isolating the stP13–stP35 interval from strain Bergerac-BO in a CL2a background. These congenic lines differed significantly from CL2a in lifespan, assayed in two environments (each P<0.001. We then screened for exchange of flanking markers to isolate recombinants that partition this region, because fine mapping the boundaries for overlapping heteroallelic spans can greatly narrow the implicated interval. Recombinants carrying the CL2a allele at stP35 were consistently long-lived compared to those retaining the Bergerac-BO allele (P<0.001, and more resistant to temperature elevation and paraquat (each ~1.7-fold, P<0.0001, but gained little protection from ultraviolet or peroxide stresses. Two rounds of recombinant screening, followed by fine-mapping of break-points and survival testing, narrowed the interval to 0.18 Mb (13.35–13.53 Mb containing 26 putative genes and 6 small-nuclear RNAs – a manageable number of targets for functional assessment.

  19. Leaching of the S-metolachlor herbicide associated with paraquat or glyphosate in a no-tillage system

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    Anderson Luis Nunes

    2016-09-01

    Full Text Available The combined use of desiccant and residual herbicides is a common management practice under no-tillage systems. However, the effect of desiccant herbicides and mulch on the leaching of residual herbicide is unknown. This study aimed at assessing the leaching of the S-metolachlor herbicide applied to ryegrass sequentially or in association with paraquat or glyphosate. A randomized blocks design was used, with four repetitions and treatments distributed over split-plots. The desiccant herbicides paraquat (600 g ha-1 or glyphosate (720 g ha-1 were used in the main plot, while S-metolachlor (2,800 g ha-1 was applied sequentially or in association with the desiccant herbicides in the subplots. There was also a control containing only desiccant herbicide, with no application of residual herbicide. The type of desiccant did not affect the leaching of the residual herbicide. In addition, the chosen method to apply the residual herbicide, sequentially or in association with the desiccant, did not impact the S-metolachlor behavior in the soil. The bioavailable concentration in the soil, 25 days after the application, was 90 g a.i. ha-1, at a depth of 18 cm.

  20. Persistence of paraquat in the soil and observations with other herbicides relevant to the theme of bound residues

    International Nuclear Information System (INIS)

    Hance, R.J.; Byast, T.H.

    1984-01-01

    Results from three separate experiments that have some relevance to bound residues are reported. In the first, 14 C-labelled paraquat was lost when applied to soil in the field, about 26% of the radioactivity disappearing in 15 months, whereas in laboratory incubation studies there was no loss of radioactivity in one year. Two possible explanations are (i) that there was photolytic decomposition in the field, (ii) the preparation of the soil for the laboratory study upset the microbial ecology of the soil to the detriment of organisms that can degrade paraquat. In an experiment with 14 C-labelled isoproturon, there was an indication that there was slightly more 14 C in the unextractable humin fraction in soil in which wheat plants were grown than in bare soil. Work in the UK, Federal Republic of Germany and in Switzerland has shown that the phytotoxicity of residues of atrazine, carbetamide, chloridazone, propyzamide, simazine, lenacil, monolinuron, linuron, propachlor and methabenzthiazuron can be satisfactorily predicted on the basis of the amount that is extractable with water. This implies that bound residues of these compounds, if they exist, are unlikely to be phytotoxic. (author)

  1. Electrochemical impedance spectroscopy for analytical determination of paraquat in meconium samples using an immunosensor modified with fullerene, ferrocene and ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Sun Xiulan [State Key Laboratory of Food Science and Technology, Wuxi 214122 (China); Li Zaijun, E-mail: zaijunli@263.ne [School of Chemical and Materials Engineering, Jiangnan University, Lihu Road 1800, Wuxi 214122 (China); Cai, Yan; Wei, Zhilei [School of Chemical and Materials Engineering, Jiangnan University, Lihu Road 1800, Wuxi 214122 (China); Fang Yinjun; Ren Guoxiao; Huang Yaru [Zhejiang Zanyu Technology Limited Corporation, Hangzhou 311215 (China)

    2011-01-01

    The paper reports a highly sensitive electrochemical immunosensor for the detection of paraquat. The immunosensor bases on glassy carbon electrode modified with a composite made from fullerene, ferrocene and the ionic liquid. The components were immobilized on the electrode surface by chitosan. The antibody of paraquat was covalently conjugated to the surface which was then blocked with bovine serum albumin. Analytical characteristics of the immunosensor were investigated by electrochemical impedance spectroscopy. It offers good repeatability (RSD = 1.5%), a stability of more than 150 days, an impedimetric response to paraquat in the range from 3.89 x 10{sup -11} to 4.0 x 10{sup -8} mol L{sup -1}, and a detection limit (S/N = 3) of 9.0 x 10{sup -12} mol L{sup -1}. The effects of omitting fullerene and the ionic liquid were well tested. The results indicated that sensitivity of the immunosensor is 3.7-fold better if fullerene and ionic liquid are used. This demonstrates that fullerene facilitates electron transfer on surface of the electrode due to unique electrochemical properties, while the ionic liquid provides biocompatible microenvironment for the antibody, which results in the enhanced sensitivity and stability. Moreover, surface morphology feature and electrochemical properties of the electrode were also examined. The method was satisfactorily applied to the determination of paraquat in meconium.

  2. The role of paraquat (1,1-dimethyl-4,4-bipyridinium chloride) and glyphosate (n-phosphonomethyl glycine) in translocation of metal ions to subsurface soils

    International Nuclear Information System (INIS)

    Mbuk, R.O.; Sha'Ato, R.; Nkpa, N.N.

    2009-01-01

    We investigated the role of paraquat (1,1'-Dimethyl-4,4'-bipyridinium dichloride) and glyphosate (N-(phosphonomethyl) glycine), on the translocation of some metals (K, Mg(II), Mn(II), Fe(II), Pb(II), Cu(II) and Cd(II)) in soil, using a topsoil (Aquic Ustifluvent: USDA Soil Taxonomy, 2000) sampled at the University of Agriculture Makurdi Crop Farm, in Central Nigeria (7 degree 47'N, 8 degree 32'E). Employing column leaching experiments with water only on native soil and soil spiked with the metals and different levels of glyphosate or paraquat treatment, leachates were collected and analyzed for their metal contents. Results showed that in the presence of paraquat the transport of Fe(II) and Mn(II) by leaching in the soil was suppressed while that of Cu(II), K and Pb(II) was enhanced. Glyphosate, similarly suppressed Mn(II) and to some extent Fe(II) translocation in the soil; however, it enhanced the mobility of Cd(II), Cu(II), Mg(II), Pb(II) and K under similar treatment. While paraquat seemed to enhance the translocation of Mg(II) at low application rates of the herbicide, glyphosate promoted its transport only at high application rates; there was no evidence that paraquat affected the movement of Cd(II) in the soil. Our results show that the long term use of these pesticides in the field may result in the depletion of Cu(II), K and Mg(II) in agricultural soils, and that the use of glyphosate may present the additional risk of possible groundwater contamination with Cd(II) and Pb(II). (author)

  3. Adiponectin attenuates lung fibroblasts activation and pulmonary fibrosis induced by paraquat.

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    Rong Yao

    Full Text Available Pulmonary fibrosis is one of the most common complications of paraquat (PQ poisoning, which demands for more effective therapies. Accumulating evidence suggests adiponectin (APN may be a promising therapy against fibrotic diseases. In the current study, we determine whether the exogenous globular APN isoform protects against pulmonary fibrosis in PQ-treated mice and human lung fibroblasts, and dissect the responsible underlying mechanisms. BALB/C mice were divided into control group, PQ group, PQ + low-dose APN group, and PQ + high-dose APN group. Mice were sacrificed 3, 7, 14, and 21 days after PQ treatment. We compared pulmonary histopathological changes among different groups on the basis of fibrosis scores, TGF-β1, CTGF and α-SMA pulmonary content via Western blot and real-time quantitative fluorescence-PCR (RT-PCR. Blood levels of MMP-9 and TIMP-1 were determined by ELISA. Human lung fibroblasts WI-38 were divided into control group, PQ group, APN group, and APN receptor (AdipoR 1 small-interfering RNA (siRNA group. Fibroblasts were collected 24, 48, and 72 hours after PQ exposure for assay. Cell viability and apoptosis were determined via Kit-8 (CCK-8 and fluorescein Annexin V-FITC/PI double labeling. The protein and mRNA expression level of collagen type III, AdipoR1, and AdipoR2 were measured by Western blot and RT-PCR. APN treatment significantly decreased the lung fibrosis scores, protein and mRNA expression of pulmonary TGF-β1, CTGF and α-SMA content, and blood MMP-9 and TIMP-1 in a dose-dependent manner (p<0.05. Pretreatment with APN significantly attenuated the reduced cell viability and up-regulated collagen type III expression induced by PQ in lung fibroblasts, (p<0.05. APN pretreatment up-regulated AdipoR1, but not AdipoR2, expression in WI-38 fibroblasts. AdipoR1 siRNA abrogated APN-mediated protective effects in PQ-exposed fibroblasts. Taken together, our data suggests APN protects against PQ-induced pulmonary fibrosis in a

  4. The effect of paraquat inhalation on parkinsonism, organ morphology and anatomy of mice and its recovery with the application of etliringea hemisphaerica (blume, r.m. smith) crude extract

    Science.gov (United States)

    Muslim, Choirul; Nurul Kamila, Santi

    2018-03-01

    This research is aimed to understand the effect of paraquat herbicide inhalation on Parkinsonism, morphology and anatomy change in mice, and its recovery with Etliringea hemisphaerica crude extract application. Sixty mice were placed into three following groups: group R0 were mice receiving standard food ransom, R1 were a group of mice receiving the regular food ransom plus inhalation of 1% paraquat, and R2 were a group of R1 plus obtaining 0,39mg/bw extract E. hemisphaerica (Bl.) R.M. Smith). After 2 X 7 days of sub-sequential application of both paraquat and “helani tulip” extract, we observed the effects. The examination included bradikinesia attitude, postural instability and rigidity, morphology and anatomy of brain, liver, blood, lung, and kidney. The data were tabulated and analyzed qualitative and semi quantitative description on the behavioural disorder, the alteration of morphology and anatomy, and their remedy based on Sander 2004, Junqueira and Carneiro, 2007. The results showed that the application of paraquat caused strong bradikinesia, postural instability and rigidity. The treatment of the extract was only resulting in the bradikinesia removal but was minor improving the consequence of postural instability and rigidity. Paraquat was not affecting the morphology of neural brain but was altering the morphology and anatomy of lung, liver, blood, and the kidney. In general, the negative impact of the paraquat was weakly eliminated by the treatment of “helani tulip” extract.

  5. Efecto del control de malezas con paraquat y glifosato sobre la erosión y pérdida de nutrimentos del suelo en cafeto

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    Robin G\\u00F3mez G\\u00F3mez

    2005-01-01

    Full Text Available Efecto del control de malezas con paraquat y glifosatosobre la erosión y pérdida de nutrimentos del suelo encafeto. En Alajuela, Costa Rica, se realizó un experimento enlos años 2002 y 2003 tendiente a determinar el control de malezas, la dinámica poblacional de las malezas y la erosión ypérdida de nutrimentos del suelo debido a aplicaciones sucesivas de paraquat y glifosato. Dos parcelas de 900 m2dentrode una plantación de café fueron aplicadas con paraquat y dosmás tratadas con glifosato. En el año 2003 una parcela de ca-da tratamiento fue disturbada aplicándole materia orgánica(broza de café y carbonato de calcio. El agua de escorrentía ylos sedimentos provenientes de parcelas de 2x7m fueron recogidos en colectores de 200 litros de capacidad y se midieronlas pérdidas de nutrientes. Al inicio de los tratamientos el control de malezas con ambos herbicidas fue de 90-100%, posteriormente con las continuas aplicaciones de herbicidas, sepresentaron malezas tolerantes, haciendo necesario el controlmecánico y aumentar la dosis del herbicida para controlarlas.Durante el 2002 las pérdidas de suelo de las parcelas tratadascon glifosato fueron el doble (3,956 t/ha comparadas con lasocurridas en las parcelas aplicadas con paraquat (1,936 t/ha.En el 2003, en las parcelas no disturbadas tratadas con paraquat se determinó menos erosión (0,231 t/ha en comparacióncon 0,329 t/ha en aquellas aplicadas con glifosato. Asimismo,en las parcelas disturbadas por enmiendas las pérdidas fueronmenores en las aplicadas con paraquat: 0,170 vs. 0,187 t/ha deglifosato. Los análisis de sedimentos y agua mostraron unapérdida importante de Ca, Mg y K, similar en ambos tratamientos. El rendimiento estimado en el año 2003 fue muy similar en ambos tratamientos

  6. Development of a sequential injection-square wave voltammetry method for determination of paraquat in water samples employing the hanging mercury drop electrode.

    Science.gov (United States)

    dos Santos, Luciana B O; Infante, Carlos M C; Masini, Jorge C

    2010-03-01

    This work describes the development and optimization of a sequential injection method to automate the determination of paraquat by square-wave voltammetry employing a hanging mercury drop electrode. Automation by sequential injection enhanced the sampling throughput, improving the sensitivity and precision of the measurements as a consequence of the highly reproducible and efficient conditions of mass transport of the analyte toward the electrode surface. For instance, 212 analyses can be made per hour if the sample/standard solution is prepared off-line and the sequential injection system is used just to inject the solution towards the flow cell. In-line sample conditioning reduces the sampling frequency to 44 h(-1). Experiments were performed in 0.10 M NaCl, which was the carrier solution, using a frequency of 200 Hz, a pulse height of 25 mV, a potential step of 2 mV, and a flow rate of 100 µL s(-1). For a concentration range between 0.010 and 0.25 mg L(-1), the current (i(p), µA) read at the potential corresponding to the peak maximum fitted the following linear equation with the paraquat concentration (mg L(-1)): i(p) = (-20.5 ± 0.3)C (paraquat) - (0.02 ± 0.03). The limits of detection and quantification were 2.0 and 7.0 µg L(-1), respectively. The accuracy of the method was evaluated by recovery studies using spiked water samples that were also analyzed by molecular absorption spectrophotometry after reduction of paraquat with sodium dithionite in an alkaline medium. No evidence of statistically significant differences between the two methods was observed at the 95% confidence level.

  7. Multiple resistance to glyphosate, paraquat and ACCase-inhibiting herbicides in Italian ryegrass populations from California: confirmation and mechanisms of resistance.

    Science.gov (United States)

    Tehranchian, Parsa; Nandula, Vijay; Jugulam, Mithila; Putta, Karthik; Jasieniuk, Marie

    2018-04-01

    Glyphosate, paraquat and acetyl CoA carboxylase (ACCase)-inhibiting herbicides are widely used in California annual and perennial cropping systems. Recently, glyphosate, paraquat, and ACCase- and acetolactate synthase (ALS)-inhibitor resistance was confirmed in several Italian ryegrass populations from the Central Valley of California. This research characterized the possible mechanisms of resistance. Multiple-resistant populations (MR1, MR2) are resistant to several herbicides from at least three modes of action. Dose-response experiments revealed that the MR1 population was 45.9-, 122.7- and 20.5-fold, and the MR2 population was 24.8-, 93.9- and 4.0-fold less susceptible to glyphosate, sethoxydim and paraquat, respectively, than the susceptible (Sus) population. Accumulation of shikimate in Sus plants was significantly greater than in MR plants 32 h after light pretreatments. Glyphosate resistance in MR plants was at least partially due to Pro106-to-Ala and Pro106-to-Thr substitutions at site 106 of 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). EPSPS gene copy number and expression level were similar in plants from the Sus and MR populations. An Ile1781-to-Leu substitution in ACCase gene of MR plants conferred a high level of resistance to sethoxydim and cross-resistance to other ACCase-inhibitors. Radiolabeled herbicide studies and phosphorimaging indicated that MR plants had restricted translocation of 14 C-paraquat to untreated leaves compared to Sus plants. This study shows that multiple herbicide resistance in Italian ryegrass populations in California, USA, is due to both target-site and non-target-site resistance mechanisms. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  8. The Intervention of Sucralfate Suspension Gel on Paraquat Poisoned Patients%硫糖铝干预百草枯中毒的研究

    Institute of Scientific and Technical Information of China (English)

    朱峻波; 于勇涛; 李洪波; 郑粉双; 苏敬; 杨春爱

    2016-01-01

    目的:探讨硫糖铝治疗百草枯中毒患者的疗效。方法:将100例百草枯中毒的患者分成两组,对照组(50例)与硫糖铝治疗组(50)例,经治疗后对比病人的死亡率,生存率和肺损伤的情况。结果:硫糖铝治疗组病人肺损伤下降,出院时间缩短。结论:早期使用硫糖铝进行胃肠灌洗的病人肺损伤下降,提高了生存率。%Objective: To investigate the effect of sucralfate suspension gel in paraquat-poisoned patients. Methods: 100 paraquat-poisoned patients were divided into two groups: control group (50) and sucralfate suspension gel group (50). The death rate, survival rate and the acute lung injury of the patients after treatment were compared between two groups. Results: The acute lung injury in the sucralfate suspension gel group more reduced, and their recovery time was shorter. Conclusions: Early use of sucralfate suspension gel reduced the acute lung injury reduced, improved the survival rate in paraquat-poisoned patients.

  9. Efeito do dessecante paraquat na qualidade da fração lipídica da soja Effects of paraquat on the quality of lipidic fraction of soybean

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    José Carlos Gomes

    2003-02-01

    Full Text Available Para se determinar a qualidade da fração lipídica de grãos de soja submetidas à aplicação do dessecante bipiridílio (paraquat, foram estudados a composição química e os índices químicos de 3 (três amostras de óleo bruto e 1 (uma amostra de óleo refinado. Os óleos analisados no presente trabalho foram provenientes da região de Itumbiara - GO, extraídos de grãos de soja submetidos ou não à aplicação de paraquat. Utilizaram-se também amostras de óleo bruto extraídas por solvente, em laboratório, provenientes de grãos de soja sujeitos ou não à aplicação de dessecante. Nenhum resíduo do dessecante foi detectado, sensibilidade de 0,01 µg/g. O perfil de ácidos graxos, medido pelos teores dos ácidos palmítico, esteárico, oléico, linoléico e linolênico, encontrara-se dentro das faixas convencionais do óleo de soja de 9 a 4,5, 2,5 a 5,0, 18 a 34, 45 a 60 e 3,5 a 8,0%, respectivamente. No entanto, os índices de saponificação (de 161 a 171 ficaram abaixo dos valores estabelecidos pela legislação brasileira (189 a 198. Já os ácidos graxos livres, matéria insaponificável dos óleos brutos, e o índice de iodo do óleo refinado estão dentro desses padrões, máximos de 2,0%, 1,5% e 120 a 143, respectivamente. Os teores de ferro e de cadmio de 1,45 e 0,39 µg/g, respectivamente, de óleo refinado, atendem à legislação. Não se detectou chumbo, à sensibilidade de 0,01 µg/g. Esses metais foram analisados por espectrofotometria de absorção atômica.In order to determine the quality of lipidic fraction of soybean seeds from plants submitted to paraquat application, the composition and chemical indices of three crude extracts and one refined oil were studied. All samples were from Itumbiara-GO , Brazil. No residues of bipiridyls were detected, sensitivity less than 0.01µg/g. Fat acids profile, measured through palmitic, estearic, oleic, linoleic and linolenic acids were as espected for soybean oils

  10. Porous Se@SiO2 nanospheres treated paraquat-induced acute lung injury by resisting oxidative stress

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    Zhu Y

    2017-09-01

    Full Text Available Yong Zhu,1,* Guoying Deng,2,* Anqi Ji,2 Jiayi Yao,1 Xiaoxiao Meng,1 Jinfeng Wang,1 Qian Wang,2 Qiugen Wang,2 Ruilan Wang1 1Department of Critical Care Medicine, Shanghai General Hospital, Shanghai Jiaotong University, School of Medicine, 2Trauma Center, Shanghai General Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai, China *These authors contributed equally to this work Abstract: Acute paraquat (PQ poisoning is one of the most common forms of pesticide poisoning. Oxidative stress and inflammation are thought to be important mechanisms in PQ-induced acute lung injury (ALI. Selenium (Se can scavenge intracellular free radicals directly or indirectly. In this study, we investigated whether porous Se@SiO2 nanospheres could alleviate oxidative stress and inflammation in PQ-induced ALI. Male Sprague Dawley rats and RLE-6TN cells were used in this study. Rats were categorized into 3 groups: control (n=6, PQ (n=18, and PQ + Se@SiO2 (n=18. The PQ and PQ + Se@SiO2 groups were randomly and evenly divided into 3 sub-groups according to different time points (24, 48 and 72 h after PQ treatment. Porous Se@SiO2 nanospheres 1 mg/kg (in the PQ + Se@SiO2 group were administered via intraperitoneal injection every 24 h. Expression levels of reduced glutathione, malondialdehyde, superoxide dismutase, reactive oxygen species (ROS, nuclear factor-κB (NF-κB, phosphorylated NF-κB (p-NF-κB, tumor necrosis factor-α and interleukin-1β were detected, and a histological analysis of rat lung tissues was performed. The results showed that the levels of ROS, malondialdehyde, NF-κB, p-NF-κB, tumor necrosis factor-α and interleukin-1β were markedly increased after PQ treatment. Glutathione and superoxide dismutase levels were reduced. However, treatment with porous Se@SiO2 nanospheres markedly alleviated PQ-induced oxidative stress and inflammation. Additionally, the results from histological examinations and wet-to-dry weight ratios of rat lung

  11. Connective tissue growth factor stimulates the proliferation, migration and differentiation of lung fibroblasts during paraquat-induced pulmonary fibrosis.

    Science.gov (United States)

    Yang, Zhizhou; Sun, Zhaorui; Liu, Hongmei; Ren, Yi; Shao, Danbing; Zhang, Wei; Lin, Jinfeng; Wolfram, Joy; Wang, Feng; Nie, Shinan

    2015-07-01

    It is well established that paraquat (PQ) poisoning can cause severe lung injury during the early stages of exposure, finally leading to irreversible pulmonary fibrosis. Connective tissue growth factor (CTGF) is an essential growth factor that is involved in tissue repair and pulmonary fibrogenesis. In the present study, the role of CTGF was examined in a rat model of pulmonary fibrosis induced by PQ poisoning. Histological examination revealed interstitial edema and extensive cellular thickening of interalveolar septa at the early stages of poisoning. At 2 weeks after PQ administration, lung tissue sections exhibited a marked thickening of the alveolar walls with an accumulation of interstitial cells with a fibroblastic appearance. Masson's trichrome staining revealed a patchy distribution of collagen deposition, indicating pulmonary fibrogenesis. Western blot analysis and immunohistochemical staining of tissue samples demonstrated that CTGF expression was significantly upregulated in the PQ-treated group. Similarly, PQ treatment of MRC-5 human lung fibroblast cells caused an increase in CTGF in a dose-dependent manner. Furthermore, the addition of CTGF to MRC-5 cells triggered cellular proliferation and migration. In addition, CTGF induced the differentiation of fibroblasts to myofibroblasts, as was evident from increased expression of α-smooth muscle actin (α-SMA) and collagen. These findings demonstrate that PQ causes increased CTGF expression, which triggers proliferation, migration and differentiation of lung fibroblasts. Therefore, CTGF may be important in PQ-induced pulmonary fibrogenesis, rendering this growth factor a potential pharmacological target for reducing lung injury.

  12. Electrochemical determination of paraquat in citric fruit based on electrodeposition of silver particles onto carbon paste electrode.

    Science.gov (United States)

    Farahi, Abdelfettah; Achak, Mounia; El Gaini, Laila; El Mhammedi, Moulay Abderrahim; Bakasse, Mina

    2015-09-01

    Carbon paste electrodes (CPEs) modified with silver particles present an interesting tool in the determination of paraquat (PQ) using square wave voltammetry. Metallic silver particle deposits have been obtained via electrochemical deposition in acidic media using cyclic voltammetry. Scanning electron microscopy and X-ray diffraction measurements show that the silver particles are deposited onto carbon surfaces in aggregate form. The response of PQ with modified electrode (Ag-CPE) related to Ag/CP loading, preconcentration time, and measuring solution pH was investigated. The result shows that the increase in the two cathodic peak currents (Peak 1 and Peak 2), under optimized conditions, was linear with the increase in PQ concentration in the range 1.0 × 10 -7  mol/L to 1.0 × 10 -3  mol/L. The detection limit and quantification limit were 2.01 × 10 -8  mol/L and 6.073 × 10 -8  mol/L, respectively for Peak 1. The precision expressed as relative standard deviation for the concentration level 1.0 × 10 -5  mol/L (n = 8) was found to be 1.45%. The methodology was satisfactorily applied for the determination of PQ in citric fruit cultures. Copyright © 2015. Published by Elsevier B.V.

  13. Differential Effects of Methyl-4-Phenylpyridinium Ion, Rotenone, and Paraquat on Differentiated SH-SY5Y Cells

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    João Barbosa Martins

    2013-01-01

    Full Text Available Paraquat (PQ, a cationic nonselective bipyridyl herbicide, has been used as neurotoxicant to modulate Parkinson’s disease in laboratory settings. Other compounds like rotenone (ROT, a pesticide, and 1-methyl-4-phenylpyridinium ion (MPP+ have been widely used as neurotoxicants. We compared the toxicity of these three neurotoxicants using differentiated dopaminergic SH-SY5Y human cells, aiming to elucidate their differential effects. PQ-induced neurotoxicity was shown to be concentration and time dependent, being mitochondrial dysfunction followed by neuronal death. On the other hand, cells exposure to MPP+ induced mitochondrial dysfunction, but not cellular lyses. Meanwhile, ROT promoted both mitochondrial dysfunction and neuronal death, revealing a biphasic pattern. To further elucidate PQ neurotoxic mechanism, several protective agents were used. SH-SY5Y cells pretreatment with tiron (TIR and 2-hydroxybenzoic acid sodium salt (NaSAL, both antioxidants, and Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME, a nitric oxide synthase inhibitor, partially protected against PQ-induced cell injury. Additionally, 1-(2-[bis(4-fluorophenylmethoxy]ethyl-4-(3-phenyl-propylpiperazine (GBR 12909, a dopamine transporter inhibitor, and cycloheximide (CHX, a protein synthesis inhibitor, also partially protected against PQ-induced cell injury. In conclusion, we demonstrated that PQ, MPP+, and ROT exerted differential toxic effects on dopaminergic cells. PQ neurotoxicity occurred through exacerbated oxidative stress, with involvement of uptake through the dopamine transporter and protein synthesis.

  14. DNaseI Protects against Paraquat-Induced Acute Lung Injury and Pulmonary Fibrosis Mediated by Mitochondrial DNA

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    Guo Li

    2015-01-01

    Full Text Available Background. Paraquat (PQ poisoning is a lethal toxicological challenge that served as a disease model of acute lung injury and pulmonary fibrosis, but the mechanism is undetermined and no effective treatment has been discovered. Methods and Findings. We demonstrated that PQ injures mitochondria and leads to mtDNA release. The mtDNA mediated PBMC recruitment and stimulated the alveolar epithelial cell production of TGF-β1 in vitro. The levels of mtDNA in circulation and bronchial alveolar lavage fluid (BALF were elevated in a mouse of PQ-induced lung injury. DNaseI could protect PQ-induced lung injury and significantly improved survival. Acute lung injury markers, such as TNFα, IL-1β, and IL-6, and marker of fibrosis, collagen I, were downregulated in parallel with the elimination of mtDNA by DNaseI. These data indicate a possible mechanism for PQ-induced, mtDNA-mediated lung injury, which may be shared by other causes of lung injury, as suggested by the same protective effect of DNaseI in bleomycin-induced lung injury model. Interestingly, increased mtDNA in the BALF of patients with amyopathic dermatomyositis-interstitial lung disease can be appreciated. Conclusions. DNaseI targeting mtDNA may be a promising approach for the treatment of PQ-induced acute lung injury and pulmonary fibrosis that merits fast tracking through clinical trials.

  15. Testing the effect of paraquat exposure on genomic recombination rates in queens of the western honey bee, Apis mellifera.

    Science.gov (United States)

    Langberg, Kurt; Phillips, Matthew; Rueppell, Olav

    2018-04-01

    The rate of genomic recombination displays evolutionary plasticity and can even vary in response to environmental factors. The western honey bee (Apis mellifera L.) has an extremely high genomic recombination rate but the mechanistic basis for this genome-wide upregulation is not understood. Based on the hypothesis that meiotic recombination and DNA damage repair share common mechanisms in honey bees as in other organisms, we predicted that oxidative stress leads to an increase in recombination rate in honey bees. To test this prediction, we subjected honey bee queens to oxidative stress by paraquat injection and measured the rates of genomic recombination in select genome intervals of offspring produced before and after injection. The evaluation of 26 genome intervals in a total of over 1750 offspring of 11 queens by microsatellite genotyping revealed several significant effects but no overall evidence for a mechanistic link between oxidative stress and increased recombination was found. The results weaken the notion that DNA repair enzymes have a regulatory function in the high rate of meiotic recombination of honey bees, but they do not provide evidence against functional overlap between meiotic recombination and DNA damage repair in honey bees and more mechanistic studies are needed.

  16. Electrochemical determination of paraquat in citric fruit based on electrodeposition of silver particles onto carbon paste electrode

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    Abdelfettah Farahi

    2015-09-01

    Full Text Available Carbon paste electrodes (CPEs modified with silver particles present an interesting tool in the determination of paraquat (PQ using square wave voltammetry. Metallic silver particle deposits have been obtained via electrochemical deposition in acidic media using cyclic voltammetry. Scanning electron microscopy and X-ray diffraction measurements show that the silver particles are deposited onto carbon surfaces in aggregate form. The response of PQ with modified electrode (Ag-CPE related to Ag/CP loading, preconcentration time, and measuring solution pH was investigated. The result shows that the increase in the two cathodic peak currents (Peak 1 and Peak 2, under optimized conditions, was linear with the increase in PQ concentration in the range 1.0 × 10−7 mol/L to 1.0 × 10−3 mol/L. The detection limit and quantification limit were 2.01 × 10−8 mol/L and 6.073 × 10−8 mol/L, respectively for Peak 1. The precision expressed as relative standard deviation for the concentration level 1.0 × 10−5 mol/L (n = 8 was found to be 1.45%. The methodology was satisfactorily applied for the determination of PQ in citric fruit cultures.

  17. Efeitos dos herbicidas glyphosate e paraquat, aplicados ao solo, sobre a emergência de feijão e soja e de algumas espécies daninhas Effects of the herbicides glyphosate and paraquat, applied to the soil, on the emergence of dry beans and soybeans and some weed species

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    C.A. Dias

    1982-06-01

    Full Text Available Em trabalho conduzido a campo na Estação Experimental Agronômica da UFRGS, Guaíba, RS em 1979/80, usaram-se os herbicidas glyphosate, paraquat e sua combinação, objetivando determinar os efe itos de doses e de épocas de aplicação destes herbicidas em plântulas de feijão e de soja e sobre nutrientes do solo. Pelos resultados obtidos para emergência e peso de maté ria seca da parte aé re a de soja , não houve di ferenças para os tratamentos testados. Também não ocorreram diferenças significativas à população in ic ia l de feijão e sobre os elementos de solo analisados (Ca, Mg e K. Com relação ao peso de matéria seca da parte aérea do feijão, verificou-se que houve interação entre herbicida e doses usadas, tendo glyphosate isolado e glyphosate mais paraquat aplicados seqüencialmente nas doses máximas causado redução significativa naquele parâmetro. Com relação ao paraquat, não foram detectadas diferenças significativas entre as doses testadas.A field xeperiment was conducted during the 1979/80 growing season at the Agronomic Experimental Station of the Federal University of Rio Grande do Sul, in Guaíba, RS, Brazil, in order to evaluate the efects of rates and times of appl ication of the herbicides glyphosate, paraqu at, and the ir combin at ion, on dry beans (Phaseolus vulgaris L. and soybeans (Glvcine max (L. Merrill, and on some soil nutrierts. The results indicated no significant differences among the soybeans treatments tested fo r plant population and shoot dry weight. Also no sta ti sti cal diffe re nces occurred fo r dry beans plant population and for soil nutrients analysed (Ca, Mg, and K. For dry beans shoot dry weight, there was an interaction of herbicides and rates, where glyphosate sprayed alone and glyphosate plus paraquat applied at the maxima ra te s te sted caused significant decreases on that variable. For paraquat utilized alone, no significant effects were detected among the rates applied.

  18. Docosahexaenoic acid prevents paraquat-induced reactive oxygen species production in dopaminergic neurons via enhancement of glutathione homeostasis

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyoung Jun; Han, Jeongsu; Jang, Yunseon; Kim, Soo Jeong; Park, Ji Hoon; Seo, Kang Sik [Department of Biochemistry, College of Medicine, Chungnam National University, Daejeon (Korea, Republic of); Jeong, Soyeon; Shin, Soyeon; Lim, Kyu [Department of Biochemistry, College of Medicine, Chungnam National University, Daejeon (Korea, Republic of); Infection Signaling Network Research Center, Chungnam National University, Daejeon (Korea, Republic of); Heo, Jun Young, E-mail: junyoung3@gmail.com [Brainscience Institute, Chungnam National University, Daejeon (Korea, Republic of); Kweon, Gi Ryang, E-mail: mitochondria@cnu.ac.kr [Department of Biochemistry, College of Medicine, Chungnam National University, Daejeon (Korea, Republic of); Infection Signaling Network Research Center, Chungnam National University, Daejeon (Korea, Republic of)

    2015-01-30

    Highlights: • DHA prevents PQ-induced dopaminergic neuronal loss via decreasing of excessive ROS. • DHA increases GR and GCLm derivate GSH pool by enhancement of Nrf2 expression. • Protective mechanism is removal of PQ-induced ROS via DHA-dependent GSH pool. • DHA may be a good preventive strategy for Parkinson’s disease (PD) therapy. - Abstract: Omega-3 polyunsaturated fatty acid levels are reduced in the substantia nigra area in Parkinson’s disease patients and animal models, implicating docosahexaenoic acid (DHA) as a potential treatment for preventing Parkinson’s disease and suggesting the need for investigations into how DHA might protect against neurotoxin-induced dopaminergic neuron loss. The herbicide paraquat (PQ) induces dopaminergic neuron loss through the excessive production of reactive oxygen species (ROS). We found that treatment of dopaminergic SN4741 cells with PQ reduced cell viability in a dose-dependent manner, but pretreatment with DHA ameliorated the toxic effect of PQ. To determine the toxic mechanism of PQ, we measured intracellular ROS content in different organelles with specific dyes. As expected, all types of ROS were increased by PQ treatment, but DHA pretreatment selectively decreased cytosolic hydrogen peroxide content. Furthermore, DHA treatment-induced increases in glutathione reductase and glutamate cysteine ligase modifier subunit (GCLm) mRNA expression were positively correlated with glutathione (GSH) content. Consistent with this increase in GCLm mRNA levels, Western blot analysis revealed that DHA pretreatment increased nuclear factor-erythroid 2 related factor 2 (Nrf2) protein levels. These findings indicate that DHA prevents PQ-induced neuronal cell loss by enhancing Nrf2-regulated GSH homeostasis.

  19. Effect of paraquat-induced oxidative stress on gene expression and aging of the filamentous ascomycete Podospora anserina

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    Matthias Wiemer

    2014-06-01

    Full Text Available Aging of biological systems is influenced by various factors, conditions and processes. Among others, processes allowing organisms to deal with various types of stress are of key importance. In particular, oxidative stress as the result of the generation of reactive oxygen species (ROS at the mitochondrial respiratory chain and the accumulation of ROS-induced molecular damage has been strongly linked to aging. Here we view the impact of ROS from a different angle: their role in the control of gene expression. We report a genome-wide transcriptome analysis of the fungal aging model Podospora anserina grown on medium containing paraquat (PQ. This treatment leads to an increased cellular generation and release of H2O2, a reduced growth rate, and a decrease in lifespan. The combined challenge by PQ and copper has a synergistic negative effect on growth and lifespan. The data from the transcriptome analysis of the wild type cultivated under PQ-stress and their comparison to those of a longitudinal aging study as well as of a copper-uptake longevity mutant of P. anserina revealed that PQ-stress leads to the up-regulation of transcripts coding for components involved in mitochondrial remodeling. PQ also affects the expression of copper-regulated genes suggesting an increase of cytoplasmic copper levels as it has been demonstrated earlier to occur during aging of P. anserina and during senescence of human fibroblasts. This effect may result from the induction of the mitochondrial permeability transition pore via PQ-induced ROS, leading to programmed cell death as part of an evolutionary conserved mechanism involved in biological aging and lifespan control.

  20. Prolonged methylprednisolone therapy after the pulse treatment for patients with moderate-to-severe paraquat poisoning: A retrospective analysis.

    Science.gov (United States)

    Gao, Jie; Feng, ShunYi; Wang, Jian; Yang, SiYuan; Li, Yong

    2017-06-01

    This retrospective study aims to evaluate the effect of prolonged methylprednisolone (MP) therapy on the mortality of patients with moderate-to-severe paraquat (PQ) poisoning after the pulse treatment.We performed a retrospective analysis of patients with acute moderate-to-severe PQ poisoning that were admitted to the emergency department from May 2012 to August 2016. Out of 138 patients, 60 were treated with pulse treatment (15 mg kg day MP for 3 days) and 78 were treated with prolonged MP therapy after pulse treatment (15 mg kg day MP for 3 days; afterward, the dosage was reduced in half every 2 days, and the MP therapy was terminated until 0.47 mg kg day). Kaplan-Meier method was used to compare the mortality between the 2 groups. Cox proportional hazard models were used to estimate the hazard ratios (HR) and 95% confidence intervals (CI).The mortality of the prolonged MP therapy after pulse treatment group was lower than that of the pulse group (47.4% vs 63.3%; log-rank tests, P  =  .003). According to the multivariate Cox analysis, the prolonged MP therapy after pulse treatment was significantly associated with a lower mortality risk (HR: 0.31, 95% CI: 0.19-0.52, P treatment caused more incidences of leucopenia than the pulse treatment alone (25.6% vs 11.7%, P  =  .04).The prolonged MP therapy after pulse treatment can reduce the mortality of moderate-to-severe PQ poisoning patients.

  1. Docosahexaenoic acid prevents paraquat-induced reactive oxygen species production in dopaminergic neurons via enhancement of glutathione homeostasis

    International Nuclear Information System (INIS)

    Lee, Hyoung Jun; Han, Jeongsu; Jang, Yunseon; Kim, Soo Jeong; Park, Ji Hoon; Seo, Kang Sik; Jeong, Soyeon; Shin, Soyeon; Lim, Kyu; Heo, Jun Young; Kweon, Gi Ryang

    2015-01-01

    Highlights: • DHA prevents PQ-induced dopaminergic neuronal loss via decreasing of excessive ROS. • DHA increases GR and GCLm derivate GSH pool by enhancement of Nrf2 expression. • Protective mechanism is removal of PQ-induced ROS via DHA-dependent GSH pool. • DHA may be a good preventive strategy for Parkinson’s disease (PD) therapy. - Abstract: Omega-3 polyunsaturated fatty acid levels are reduced in the substantia nigra area in Parkinson’s disease patients and animal models, implicating docosahexaenoic acid (DHA) as a potential treatment for preventing Parkinson’s disease and suggesting the need for investigations into how DHA might protect against neurotoxin-induced dopaminergic neuron loss. The herbicide paraquat (PQ) induces dopaminergic neuron loss through the excessive production of reactive oxygen species (ROS). We found that treatment of dopaminergic SN4741 cells with PQ reduced cell viability in a dose-dependent manner, but pretreatment with DHA ameliorated the toxic effect of PQ. To determine the toxic mechanism of PQ, we measured intracellular ROS content in different organelles with specific dyes. As expected, all types of ROS were increased by PQ treatment, but DHA pretreatment selectively decreased cytosolic hydrogen peroxide content. Furthermore, DHA treatment-induced increases in glutathione reductase and glutamate cysteine ligase modifier subunit (GCLm) mRNA expression were positively correlated with glutathione (GSH) content. Consistent with this increase in GCLm mRNA levels, Western blot analysis revealed that DHA pretreatment increased nuclear factor-erythroid 2 related factor 2 (Nrf2) protein levels. These findings indicate that DHA prevents PQ-induced neuronal cell loss by enhancing Nrf2-regulated GSH homeostasis

  2. The in vivo antioxidant effect of vitamin C on hemogram in Paraquat treated male rats (rattus norvegicus

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    Benjamin Nnamdi Okolonkwo

    2013-06-01

    Full Text Available Paraquat (PQ is one of the most used herbicide globally; applied around trees in orchards and between crop rows to control broad-leaved and grassy weeds. Its oxidation results in the formation of superoxides which causes damage to cellular components. In this study, we determined the antioxidant effect vitamin C has on hemograms [hemoglobin (Hb, packed cell volume (PCV and total white blood cells count] of rats under these toxic insults. The animals grouped (A-D, comprising subgroups without vitamin C (A1, B1, C1, D1 and subgroups on vitamin C (A2, B2, C2, D2, received different sub-lethal doses of PQ administered intraperitoneally monthly to the animals over a period of three months. The Hb values obtained were significantly reduced (P≤0.05 at month 1 and (P≤0.001 at months 2 and 3. These changes became more pronounced with increased dose and time. Vitamin C treated subgroups (B2, C2 and D2 had better Hb values than those without it (B1, C1 and D1 but the values were still significantly low when compared to the control subgroups (A1 and A2. This same trend was observed in the PCV results obtained. The Control subgroups showed that vitamin C treated subgroup (A2 had a more improved hemogram values than subgroup on water only (A1, but they were all higher than that of the test subgroups. These PQ induced anaemia were ameliorated by the subsequent administration of vitamin C, and continuous treatment with vitamin C restored the health status of the animals so treated.

  3. Synthesis of [Ru3(μ3-NPh)(Br)(CO)9]- on self-assembled monolayers of di(3-aminopropyl)viologen/ITO surfaces and its application to photoelectrochemical cells

    International Nuclear Information System (INIS)

    Lee, Deok Yeon; Lee, Mi-Sun; Lim, Iseul; Kang, Soon Hyung; Nah, Yoon-Chae; Lee, Wonjoo; Han, Sung-Hwan

    2011-01-01

    Triruthenium carbonyl clusters {[Ru 3 (Br)(CO) 11 ] - (denoted as Ru-1), [Ru 3 (μ 2 -Br)(CO) 10 ] - (denoted as Ru-2), and [Ru 3 (μ 3 -NPh)(Br)(CO) 9 ] - (denoted as Ru-3)} were synthesized on di(3-aminopropyl)viologen (DAPV)/indium tin oxide (ITO) using a surface reaction in a ruthenium (III) carbonyl [Ru 3 (CO) 12 ] solution, and were applied to photoelectrochemical cells (PECs) at the molecular level. The formation of DAPV on ITO was realized in the form of self-assembled monolayers. Ru 3 (CO) 12 then easily reacted with the Br - of DAPV, and a mixture of Ru-1 and Ru-2 was formed on DAPV/ITO. Furthermore, Ru-3 was successfully anchored on DAPV/ITO by adding nitrosobenzene in order to react with Ru-2 on DAPV/ITO. The photocurrents of (Ru-1 and Ru-2)/DAPV/ITO and Ru-3/DAPV/ITO in PECs at the molecular level were 6.3 nA cm -2 and 8.6 nA cm -2 , respectively. The quantum yield of Ru-3/DAPV/ITO was ∼0.8%. Time-resolved photoluminescence spectroscopy and emission spectroscopy were recorded to bring out the photoinduced charge transfer process from ruthenium clusters to DAPV.

  4. TEMPO/viologen electrochemical heterojunction for diffusion-controlled redox mediation: a highly rectifying bilayer-sandwiched device based on cross-reaction at the interface between dissimilar redox polymers.

    Science.gov (United States)

    Tokue, Hiroshi; Oyaizu, Kenichi; Sukegawa, Takashi; Nishide, Hiroyuki

    2014-03-26

    A couple of totally reversible redox-active molecules, which are different in redox potentials, 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) and viologen (V(2+)), were employed to give rise to a rectified redox conduction effect. Single-layer and bilayer devices were fabricated using polymers containing these sites as pendant groups per repeating unit. The devices were obtained by sandwiching the redox polymer layer(s) with indium tin oxide (ITO)/glass and Pt foil electrodes. Electrochemical measurements of the single-layer device composed of polynorbornene-bearing TEMPO (PTNB) exhibited a diffusion-limited current-voltage response based on the TEMPO(+)/TEMPO exchange reaction, which was almost equivalent to a redox gradient through the PTNB layer depending upon the thickness. The bilayer device gave rise to the current rectification because of the thermodynamically favored cross-reaction between TEMPO(+) and V(+) at the polymer/polymer interface. A current-voltage response obtained for the bilayer device demonstrated a two-step diffusion-limited current behavior as a result of the concurrent V(2+)/V(+) and V(+)/V(0) exchange reactions according to the voltage and suggested that the charge transport process through the device was most likely to be rate-determined by a redox gradient in the polymer layer. Current collection experiments revealed a charge transport balance throughout the device, as a result of the electrochemical stability and robustness of the polymers in both redox states.

  5. An aqueous all-organic redox-flow battery employing a (2,2,6,6-tetramethylpiperidin-1-yl)oxyl-containing polymer as catholyte and dimethyl viologen dichloride as anolyte

    Science.gov (United States)

    Hagemann, Tino; Winsberg, Jan; Grube, Mandy; Nischang, Ivo; Janoschka, Tobias; Martin, Norbert; Hager, Martin D.; Schubert, Ulrich S.

    2018-02-01

    Herein we present a new redox-flow battery (RFB) that employs a (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) containing copolymer (P1) as catholyte and the viologen derivative N,N‧-dimethyl-4,4‧-bipyridinium dichloride (MV) as anolyte in an aqueous sodium chloride solution. This is the first time that a combination of an organic polymer and a low-molar-mass organic redox-active material is presented. The electrochemical behavior of the utilized charge-storage materials were investigated by cyclic voltammetry (CV) and feature reversible redox-reactions at E½ = 0.7 V (TEMPO/TEMPO+) and E½ = -0.6 V vs. AgCl/Ag (MV++/MV+•), which lead to a promising cell voltage of 1.3 V in the subsequent battery application. Studies were performed to determine the most suitable anion-exchange membrane (AEM), the ideal conducting salt concentration and the optimal flow rate. The resulting battery reveals a stable charge/discharge performance over 100 consecutive cycles with coulombic efficiencies of up to 95%, a high energy efficiency of 85% and an overall energy density of the electrolyte system of 3.8 W h L-1.

  6. Impact on mormortality of o one conjugated treatment in 10 paraquat intoxicated patients attended at the San Vicente de Paul University Hospital in Medellín, Colombia, from august 2002 to august 2003 Impacto en la mortalidad de un tratamiento conjugado, en pacientes intoxicados no ocupacionalmente, con paraquat en el Hospital Universitario San Vicente de Paúl de Medellín, entre agosto de 2002 y agosto de 2003

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    Luz Marina Quiceno Quiceno

    2004-01-01

    Full Text Available Paraquat is a frequently used herbicide in Colombia. Its ingestion produces a severe intoxication with a high lethality. Up to now there is not a successful treatment for it. The purpose of this study was to determine if a conjugated treatment with NAcetylcysteine; A, C, and E vitamins, Propranolol, Colchicine and Furosemide increased the survival of ten paraquat intoxicated patients attended at the San Vicente de Paul University Hospital in Medellín, Colombia, based on the predicted probability of survival, Paraquat plasmatic concentration and clinical assessment. Six patients died because of their intoxication severity, three of them due to multisystemic organic failure, and three from acute respiratory failure. The results had statistical significance, showing a direct proportion between the high plasma levels of paraquat and mortality; and the fact that those with a multiorganic involvement died, despite their low Paraquat plasma levels. Based on clinical data it is possible to conclude that the treatment is useful only for patients with mild to moderate intoxication; there is not an exact correlation between the clinical features and the Paraquat plasma levels; and the clinical features are a very good indicator of the prognosis in Paraquat intoxicated patients. Further experimental and clinical trials are needed. En Colombia se utiliza frecuentemente el Paraquat, herbicida que al ser ingerido en cualquier cantidad produce toxicidad grave y alta mortalidad, sin haberse encontrado un tratamiento eficaz para la recuperación de los intoxicados. El objetivo de este estudio fue establecer si un tratamiento conjugado con N-acetilcisteína, vitamina A, C, E, propranolol, colchicina y furosemida, disminuye la mortalidad en pacientes, basados en la probabilidad de supervivencia, los niveles plasmáticos y el seguimiento clínico. Resultados: De diez pacientes con intoxicaciones no ocupacionales que ingresaron al Hospital Universitario San Vicente

  7. PARAQUAT TOLERANCE3 Is an E3 Ligase That Switches off Activated Oxidative Response by Targeting Histone-Modifying PROTEIN METHYLTRANSFERASE4b.

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    Chao Luo

    2016-09-01

    Full Text Available Oxidative stress is unavoidable for aerobic organisms. When abiotic and biotic stresses are encountered, oxidative damage could occur in cells. To avoid this damage, defense mechanisms must be timely and efficiently modulated. While the response to oxidative stress has been extensively studied in plants, little is known about how the activated response is switched off when oxidative stress is diminished. By studying Arabidopsis mutant paraquat tolerance3, we identified the genetic locus PARAQUAT TOLERANCE3 (PQT3 as a major negative regulator of oxidative stress tolerance. PQT3, encoding an E3 ubiquitin ligase, is rapidly down-regulated by oxidative stress. PQT3 has E3 ubiquitin ligase activity in ubiquitination assay. Subsequently, we identified PRMT4b as a PQT3-interacting protein. By histone methylation, PRMT4b upregulates the expression of APX1 and GPX1, encoding two key enzymes against oxidative stress. On the other hand, PRMT4b is recognized by PQT3 for targeted degradation via 26S proteasome. Therefore, we have identified PQT3 as an E3 ligase that acts as a negative regulator of activated response to oxidative stress and found that histone modification by PRMT4b at APX1 and GPX1 loci plays an important role in oxidative stress tolerance.

  8. Glucose Metabolism and AMPK Signaling Regulate Dopaminergic Cell Death Induced by Gene (α-Synuclein)-Environment (Paraquat) Interactions.

    Science.gov (United States)

    Anandhan, Annadurai; Lei, Shulei; Levytskyy, Roman; Pappa, Aglaia; Panayiotidis, Mihalis I; Cerny, Ronald L; Khalimonchuk, Oleh; Powers, Robert; Franco, Rodrigo

    2017-07-01

    While environmental exposures are not the single cause of Parkinson's disease (PD), their interaction with genetic alterations is thought to contribute to neuronal dopaminergic degeneration. However, the mechanisms involved in dopaminergic cell death induced by gene-environment interactions remain unclear. In this work, we have revealed for the first time the role of central carbon metabolism and metabolic dysfunction in dopaminergic cell death induced by the paraquat (PQ)-α-synuclein interaction. The toxicity of PQ in dopaminergic N27 cells was significantly reduced by glucose deprivation, inhibition of hexokinase with 2-deoxy-D-glucose (2-DG), or equimolar substitution of glucose with galactose, which evidenced the contribution of glucose metabolism to PQ-induced cell death. PQ also stimulated an increase in glucose uptake, and in the levels of glucose transporter type 4 (GLUT4) and Na + -glucose transporters isoform 1 (SGLT1) proteins, but only inhibition of GLUT-like transport with STF-31 or ascorbic acid reduced PQ-induced cell death. Importantly, while autophagy protein 5 (ATG5)/unc-51 like autophagy activating kinase 1 (ULK1)-dependent autophagy protected against PQ toxicity, the inhibitory effect of glucose deprivation on cell death progression was largely independent of autophagy or mammalian target of rapamycin (mTOR) signaling. PQ selectively induced metabolomic alterations and adenosine monophosphate-activated protein kinase (AMPK) activation in the midbrain and striatum of mice chronically treated with PQ. Inhibition of AMPK signaling led to metabolic dysfunction and an enhanced sensitivity of dopaminergic cells to PQ. In addition, activation of AMPK by PQ was prevented by inhibition of the inducible nitric oxide syntase (iNOS) with 1400W, but PQ had no effect on iNOS levels. Overexpression of wild type or A53T mutant α-synuclein stimulated glucose accumulation and PQ toxicity, and this toxic synergism was reduced by inhibition of glucose metabolism

  9. Overexpression of Iron Superoxide Dismutase in Transformed Poplar Modifies the Regulation of Photosynthesis at Low CO2 Partial Pressures or Following Exposure to the Prooxidant Herbicide Methyl Viologen1

    Science.gov (United States)

    Arisi, Ana-Carolina M.; Cornic, Gabriel; Jouanin, Lise; Foyer, Christine H.

    1998-01-01

    Chloroplast-targeted overexpression of an Fe superoxide dismutase (SOD) from Arabidopsis thaliana resulted in substantially increased foliar SOD activities. Ascorbate peroxidase, glutathione reductase, and monodehydroascorbate reductase activities were similar in the leaves from all of the lines, but dehydroascorbate reductase activity was increased in the leaves of the FeSOD transformants relative to untransformed controls. Foliar H2O2, ascorbate, and glutathione contents were comparable in all lines of plants. Irradiance-dependent changes in net CO2 assimilation and chlorophyll a fluorescence quenching parameters were similar in all lines both in air (21% O2) and at low (1%) O2. CO2-response curves for photosynthesis showed similar net CO2-exchange characteristics in all lines. In contrast, values of photochemical quenching declined in leaves from untransformed controls at intercellular CO2 (Ci) values below 200 μL L−1 but remained constant with decreasing Ci in leaves of FeSOD transformants. When the O2 concentration was decreased from 21 to 1%, the effect of FeSOD overexpression on photochemical quenching at limiting Ci was abolished. At high light (1000 μmol m−2 s−1) a progressive decrease in the ratio of variable (Fv) to maximal (Fm) fluorescence was observed with decreasing temperature. At 6oC the high-light-induced decrease in the Fv/Fm ratio was partially prevented by low O2 but values were comparable in all lines. Methyl viologen caused decreased Fv/Fm ratios, but this was less marked in the FeSOD transformants than in the untransformed controls. These observations suggest that the rate of superoxide dismutation limits flux through the Mehler-peroxidase cycle in certain conditions. PMID:9625709

  10. EFECTO DEL GLIFOSATO Y PARAQUAT SOBRE EL PROCESO DE NITRIFICACION EN UN SUELO DEL CORREGIMIENTO DE RÍO FRÍO (MAGDALENA, COLOMBIA

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    Dary Luz Mendoza M.

    2010-08-01

    Full Text Available Se realizaron ensayos in vitro para determinar el efecto tóxico de los herbicidas glifosato y paraquat sobre el proceso de nitrificación con suelo franco-arenoso (pH: 5.8, Humedad: 13.05%, en el corregimiento de Río Frío, Magdalena. Los experimentos se realizaron por cuantificación espectrofométrica (método del ácido fenoldisulfonico de la concentración de nitratos producidos durante un periodo de incubación de 30 días usando el producto comercial y el principio activo grado estándard, en concentraciones de 10, 100 y 1000 ppm de cada uno de los herbicidas. Se observó una reducción de la nitrificación y un incremento en el período de retardo al aumentar las concentraciones, sin embargo, solamente con altas dosis del glifosato comercial (100 y 1000 ppm de Round Up y paraquat comercial (1000 ppm de Gramoxone hubo inhibición de la nitrificación. Tanto el paraquat comercial como el estándard, a 10 y 100 ppm, causaron leves disturbios sobre la nitrificación, la cual retornó a una normalidad relativa después de 30 días de incubación. Se observó una diferencia significativa (p<0,00\\ entre el glifosato comercial (concentración máxima de nitrato 55,0pg/g y el glifosato estándar (510,12pg/g NO3' a una concentración de 1000 ppm, lo cual sugiere que los adyuvantes en el producto comercial contribuyen a aumentar el efecto tóxico del herbicida. Estos datos son de interés para desarrollar técnicas de utilización de plaguicidas que permitan la recuperación de las poblaciones microbianas importantes para la fertilidad de los suelos.

  11. Aplicação de misturas de diuron com MSMA, e com paraquat, no controle de plantas daninhas de folhas largas em cultura de algodão (Gossypium hirsutum L. Mixture of diuron whit MSMA and with paraquat for broadleaved weeds control in cotton

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    L. S. P. Cruz

    1978-01-01

    Full Text Available Em ensaio de campo conduzido em 1975/76 procurou-se avaliar a ação de misturas de MSMA com diuron e de paraquat com diuron, aplicadas em pós-emergência, em jato dirigido, em duas épocas diferentes, no controle de algumas plantas daninhas de folhas largas em algodão: carrapicho- do-campo (Acanthospermum australe (Loef O. Kuntze , falsa-poaia (Borreria ala ta (Aubl DC, poaia-branca (Richardia brasiliensis Gomez e guanxuma (Sida spp . A vegetação natural da área do ensaio era formada ainda pela gramínea capim-de-colchão (Digitaria sanguinalis (L. Scop . Os resultados mostraram que as misturas de 2,00 kg e 2,70 kg/ha de MSMA com, respectivamente 0,30 kg e 0,40 kg/ha de diuron, e a mistura de 0.60 kg/ha de paraquat com 0,60 kg/ ha de diuron, foram eficientes no co ntro le daquelas dicotiledôneas, e também no da gramínea. Todos os tratamentos provocaram leves sintomas de fitotoxicidade nos algodoeiros, mas desapareceram depois e não prejudicaram o desenvolvimento vegetativo das plantas, assim como a produção de algodão em caroço.In a field trial carried out in 1975/76, a diuron mixtu re with MSMA and another with paraquat was tested on broadleaved weeds in cotton crops. The applications were done in postemergence, directed-spray, in two different periods. The broadleaved weeds observed in the trial were Acanthospermum australe , Borreria alata, Richardia brasiliensis, and Sida spp, also the grass Digitaria sanguinalis. Best results were obtained with the mixture of 0,60 kg/ha of paraquat with 0,60 kg/ha of diuron, and 2,70 kg/ha of MSMA with 0,40 kg/ ha of diuron, or 2,00 kg/ha of MSMA with 0,30 kg/ha of diuron. All the treatments caused sl ight symptons of toxic ity in cotton, which disappeared later and did not damage the production.

  12. Complexation of triptycene-derived macrotricyclic polyether with paraquat derivatives, diquat, and a 2,7-diazapyrenium salt: guest-induced conformational changes of the host.

    Science.gov (United States)

    Han, Ying; Cao, Jing; Li, Peng-Fei; Zong, Qian-Shou; Zhao, Jian-Min; Guo, Jia-Bin; Xiang, Jun-Feng; Chen, Chuan-Feng

    2013-04-05

    Complexation between a triptycene-derived macrotricyclic polyether containing two dibenzo-[30]-crown-10 cavities and different functionalized paraquat derivatives, diquat, and a 2,7-diazapyrenium salt in both solution and solid state was investigated in detail. It was found that depending on the guests with different terminal functional groups and structures, the macrotricyclic polyether could form 1:1 or 1:2 complexes with the guests in different complexation modes in solution and also in the solid state. Especially, the conformation of the macrotricyclic polyether was efficiently adjusted by the encapsulated guests, which was to some extent similar to substrate-induced fit of enzymes. Moreover, the binding and releasing of the guests in the complexes could be controlled by potassium ions.

  13. Salvianolic acid B protects against paraquat-induced pulmonary injury by mediating Nrf2/Nox4 redox balance and TGF-β1/Smad3 signaling

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bin, E-mail: iamicehe@163.com [Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Logistic University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Cao, Bo, E-mail: caobo19814@126.com [Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Tianjin Key Laboratory of Cardiovascular Remodeling and Target Organ Injury, Tianjin, 300162 (China); Zhang, Di, E-mail: zhangdibad@163.com [Department of Otorhinolaryngology Head and Neck Surgery, Institute of Otorhinolaryngology, Tianjin First Center Hospital, Tianjin 300192 (China); Xiao, Na [Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Logistic University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Chen, Hong [Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Li, Guo-qiang; Peng, Shou-chun [Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Logistic University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Wei, Lu-qing, E-mail: luqing-wei@163.com [Department of Respiratory and Critical Care Medicine, Affiliated Hospital of Logistic University of Chinese People' s Armed Police Force, Tianjin 300162 (China)

    2016-10-15

    The present study was aimed at exploring the protective effects of Salvianolic acid B (SalB) against paraquat (PQ)-induced lung injury in mice. Lung fibrotic injuries were induced in mice by a single intragastrical administration of 300 mg/kg PQ, then the mice were administrated with 200 mg/kg, 400 mg/kg SalB, 100 mg/kg vitamin C (Vit C) and dexamethasone (DXM) for 14 days. PQ-triggered structure distortion, collagen overproduction, excessive inflammatory infiltration, pro-inflammatory cytokine release, and oxidative stress damages in lung tissues and mortality of mice were attenuated by SalB in a dose-dependent manner. Furthermore, SalB was noted to enhance the expression and nuclear translocation of nuclear factor erythroid 2–related factor 2 (Nrf2) and reduce expression of the reactive oxygen species-generating enzyme Nox4 [NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidase-4]. SalB also inhibited the increasing expression of transforming growth factor (TGF)-β1 and the phosphorylation of its downstream target Smad3 which were enhanced by PQ. These results suggest that SalB may exert protective effects against PQ-induced lung injury and pulmonary fibrosis. Its mechanisms involve the mediation of Nrf2/Nox4 redox balance and TGF-β1/Smad3 signaling. - Highlights: • Salvianolic acid B (SalB) reduced Paraquat-induced mortality and pulmonary injury in mice. • SalB has anti-oxidation, anti-inflammatory and anti-fibrogenic effects simultaneously. • Its mechanisms were targeting Nrf2-Nox4 redox balance and TGF-β1/Smad3 signaling.

  14. Regulation by SoxR of mfsA, Which Encodes a Major Facilitator Protein Involved in Paraquat Resistance in Stenotrophomonas maltophilia.

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    Kriangsuk Srijaruskul

    Full Text Available Stenotrophomonas maltophilia MfsA (Smlt1083 is an efflux pump in the major facilitator superfamily (MFS. Deletion of mfsA renders the strain more susceptible to paraquat, but no alteration in the susceptibility levels of other oxidants is observed. The expression of mfsA is inducible upon challenge with redox cycling/superoxide-generating drug (paraquat, menadione and plumbagin treatments and is directly regulated by SoxR, which is a transcription regulator and sensor of superoxide-generating agents. Analysis of mfsA expression patterns in wild-type and a soxR mutant suggests that oxidized SoxR functions as a transcription activator of the gene. soxR (smlt1084 is located in a head-to-head fashion with mfsA, and these genes share the -10 motif of their promoter sequences. Purified SoxR specifically binds to the putative mfsA promoter motifs that contain a region that is highly homologous to the consensus SoxR binding site, and mutation of the SoxR binding site abolishes binding of purified SoxR protein. The SoxR box is located between the putative -35 and -10 promoter motifs of mfsA; and this position is typical for a promoter in which SoxR acts as a transcriptional activator. At the soxR promoter, the SoxR binding site covers the transcription start site of the soxR transcript; thus, binding of SoxR auto-represses its own transcription. Taken together, our results reveal for the first time that mfsA is a novel member of the SoxR regulon and that SoxR binds and directly regulates its expression.

  15. Salvianolic acid B protects against paraquat-induced pulmonary injury by mediating Nrf2/Nox4 redox balance and TGF-β1/Smad3 signaling

    International Nuclear Information System (INIS)

    Liu, Bin; Cao, Bo; Zhang, Di; Xiao, Na; Chen, Hong; Li, Guo-qiang; Peng, Shou-chun; Wei, Lu-qing

    2016-01-01

    The present study was aimed at exploring the protective effects of Salvianolic acid B (SalB) against paraquat (PQ)-induced lung injury in mice. Lung fibrotic injuries were induced in mice by a single intragastrical administration of 300 mg/kg PQ, then the mice were administrated with 200 mg/kg, 400 mg/kg SalB, 100 mg/kg vitamin C (Vit C) and dexamethasone (DXM) for 14 days. PQ-triggered structure distortion, collagen overproduction, excessive inflammatory infiltration, pro-inflammatory cytokine release, and oxidative stress damages in lung tissues and mortality of mice were attenuated by SalB in a dose-dependent manner. Furthermore, SalB was noted to enhance the expression and nuclear translocation of nuclear factor erythroid 2–related factor 2 (Nrf2) and reduce expression of the reactive oxygen species-generating enzyme Nox4 [NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidase-4]. SalB also inhibited the increasing expression of transforming growth factor (TGF)-β1 and the phosphorylation of its downstream target Smad3 which were enhanced by PQ. These results suggest that SalB may exert protective effects against PQ-induced lung injury and pulmonary fibrosis. Its mechanisms involve the mediation of Nrf2/Nox4 redox balance and TGF-β1/Smad3 signaling. - Highlights: • Salvianolic acid B (SalB) reduced Paraquat-induced mortality and pulmonary injury in mice. • SalB has anti-oxidation, anti-inflammatory and anti-fibrogenic effects simultaneously. • Its mechanisms were targeting Nrf2-Nox4 redox balance and TGF-β1/Smad3 signaling.

  16. Early Metabolome Profiling and Prognostic Value in Paraquat-Poisoned Patients: Based on Ultraperformance Liquid Chromatography Coupled To Quadrupole Time-of-Flight Mass Spectrometry.

    Science.gov (United States)

    Hu, Lufeng; Hong, Guangliang; Tang, Yahui; Wang, Xianqin; Wen, Congcong; Lin, Feiyan; Lu, Zhongqiu

    2017-12-18

    Paraquat (PQ) has caused countless deaths throughout the world. There remains no effective treatment for PQ poisoning. Here we study the blood metabolome of PQ-poisoned patients using ultraperformance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS). Patients were divided into groups according to blood PQ concentration. Healthy subjects served as controls. Metabolic features were statistically analyzed using multivariate pattern-recognition techniques to identify the most important metabolites. Selected metabolites were further compared with a series of clinical indexes to assess the prognostic value. PQ-poisoned patients showed substantial differences compared with healthy subjects. Based on variable of importance in the project (VIP) values and statistical analysis, 17 metabolites were selected and identified. These metabolites well-classified low PQ-poisoned patients, high PQ-poisoned patients, and healthy subjects, which was better than that of a complete blood count (CBC). Among the 17 metabolites, 20:3/18:1-PC (PC), LPA (0:0/16:0) (LPA), 19-oxo-deoxycorticosterone (19-oxo-DOC), and eicosapentaenoic acid (EPA) had prognostic value. In particular, EPA was the most sensitive one. Besides, the levels of EPA was correlated with LPA and 19-oxo-DOC. If EPA was excessively consumed, then prognosis was poor. In conclusion, the serum metabolome is substantially perturbed by PQ poisoning. EPA is the most important biomarker in early PQ poisoning.

  17. Mucuna pruriens seed extract reduces oxidative stress in nigrostriatal tissue and improves neurobehavioral activity in paraquat-induced Parkinsonian mouse model.

    Science.gov (United States)

    Yadav, Satyndra Kumar; Prakash, Jay; Chouhan, Shikha; Singh, Surya Pratap

    2013-06-01

    Parkinson's disease (PD) is a neurodegenerative disease which causes rigidity, resting tremor and postural instability. Treatment for this disease is still under investigation. Mucuna pruriens (L.), is a traditional herbal medicine, used in India since 1500 B.C., as a neuroprotective agent. In this present study, we evaluated the therapeutic effects of aqueous extract of M. pruriens (Mp) seed in Parkinsonian mouse model developed by chronic exposure to paraquat (PQ). Results of our study revealed that the nigrostriatal portion of Parkinsonian mouse brain showed significantly increased levels of nitrite, malondialdehyde (MDA) and reduced levels of catalase compared to the control. In the Parkinsonian mice hanging time was decreased, whereas narrow beam walk time and foot printing errors were increased. Treatment with aqueous seed extract of Mp significantly increased the catalase activity and decreased the MDA and nitrite level, compared to untreated Parkinsonian mouse brain. Mp treatment also improved the behavioral abnormalities. It increased hanging time, whereas it decreased narrow beam walk time and foot printing error compared to untreated Parkinsonian mouse brain. Furthermore, we observed a significant reduction in tyrosine hydroxylase (TH) immunoreactivity in the substantia nigra (SN) and striatum region of the brain, after treatment with PQ which was considerably restored by the use of Mp seed extract. Our result suggested that Mp seed extract treatment significantly reduced the PQ induced neurotoxicity as evident by decrease in oxidative damage, physiological abnormalities and immunohistochemical changes in the Parkinsonian mouse. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Paraquat-induced reactive oxygen species inhibit neutrophil apoptosis via a p38 MAPK/NF-κB-IL-6/TNF-α positive-feedback circuit.

    Directory of Open Access Journals (Sweden)

    Xiaolong Wang

    Full Text Available Paraquat (PQ, a widely used herbicide and potent reactive oxygen species (ROS inducer, can injure multiple tissues and organs, especially the lung. However, the underlying mechanism is still poorly understood. According to previous reports, neutrophil aggregation and excessive ROS production might play pivotal pathogenetic roles. In the present study, we found that PQ could prolong neutrophil lifespan and induce ROS generation in a concentration-independent manner. Activated nuclear factor-κB (NF-κB, p38 mitogen-activated kinase (p38 MAPK, and myeloid cell leukemia sequence 1 (Mcl-1 but not Akt signaling pathways were involved in this process, as well as increasing levels of interleukin-6 (IL-6, tumor necrosis factor-α (TNF-α, and IL-1β. Furthermore, the proinflammatory mediators IL-6 and TNF-α could in turn promote ROS generation, creating a vicious cycle. The existence of such a feedback loop is supported by our finding that neutrophil apoptosis is attenuated by PQ in a concentration-independent manner and could partially explain the clinical dilemma why oxygen therapy will exacerbate PQ induced tissue injury.

  19. Paraquat induces extrinsic pathway of apoptosis in A549 cells by induction of DR5 and repression of anti-apoptotic proteins, DDX3 and GSK3 expression.

    Science.gov (United States)

    Hathaichoti, Sasiphen; Visitnonthachai, Daranee; Ngamsiri, Pronrumpa; Niyomchan, Apichaya; Tsogtbayar, Oyu; Wisessaowapak, Churaibhon; Watcharasit, Piyajit; Satayavivad, Jutamaad

    2017-08-01

    Paraquat (PQ) is a bipyridyl derivative herbicide known to cause lung toxicity partly through induction of apoptosis. Here we demonstrated that PQ caused apoptosis in A549 cells. PQ increased cleavage of caspase-8 and Bid, indicating caspase-8 activation and truncated Bid, the two key mediators of extrinsic apoptosis. Additionally, PQ treatment caused an increase in DR5 (death receptor-5) and caspase-8 interaction, indicating formation of DISC (death-inducing signaling complex). These results indicate that PQ induces apoptosis through extrinsic pathway in A549 cells. Moreover, PQ drastically increased DR5 expression and membrane localization. Furthermore, PQ caused prominent concentration dependent reductions of DDX3 (the DEAD box protein-3) and GSK3 (glycogen synthase kinase-3) which can associate with DR5 and prevent DISC formation. Additionally, PQ decreased DR5-DDX3 interaction, suggesting a reduction of DDX3/GSK3 anti-apoptotic complex. Inhibition of GSK3, which is known to promote extrinsic apoptosis by its pharmacological inhibitor, BIO accentuated PQ-induced apoptosis. Moreover, GSK3 inhibition caused a further decrease in PQ-reduced DR5-DDX3 interaction. Taken together, these results suggest that PQ may induce extrinsic pathway of apoptosis in A549 cells through upregulation of DR5 and repression of anti-apoptotic proteins, DDX3/GSK3 leading to reduction of anti-apoptotic complex. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. The antioxidant effects of vitamin C on liver enzymes: aspartate aminotransferase, alanine aminotranferease, alkaline phosphatase and gamma-glutamyltransferase activities in rats under Paraquat insult

    Directory of Open Access Journals (Sweden)

    Benjamin Nnamdi Okolonkwo

    2013-06-01

    Full Text Available Paraquat (PQ is a bipyridylium herbicide; applied around trees in orchards and between crop rows to control broad-leaved and grassy weeds. Its oxidation results in the formation of superoxides which causes damage to cellular components. In this study, we determined the antioxidant effect vitamin C has on the liver enzymes [aspartate aminotransferase (SGOT, alanine aminotranferease (SGPT, alkaline phosphatase (ALP, and gamma-glutamyltransferase (GGT] of rats under this toxic insult. Male rats in groups (A, B, C and D were intraperitoneally injected with different sublethal increasing doses (0, 0.02, 0.04 and 0.06 g/kg body weigh of PQ respectively on monthly basis. Subsequently, the subgroups (A2, B2, C2 and D2 were given orally, 200 mg/L vitamin C, while the subgroups A1, B1, C1, and D1, received only water. Four animals per subgroup were decapitated on monthly basis and blood samples taken for enzyme assay. The parameters studied were - SGOT, SGPT, ALP and GGT - liver enzymes. The dose and time dependent PQ toxicity effect resulted in highly elevated Liver enzymes activities. The subgroups on vitamin C had significantly lower enzyme activities when compared to the same subgroups on only PQ insult. But the values were high when compared to the control subgroups (A1 and A2. These results were indication that vitamin C when given at moderate doses and maintained for a longer period could be a life saving adjunct to toxic insult.

  1. Pesticide risk assessment: A study on inhalation and dermal exposure to 2,4-D and paraquat among Malaysian paddy farmers.

    Science.gov (United States)

    Baharuddin, Mohd Rafee B; Sahid, Ismail B; Noor, Mohamad Azhar B Mohd; Sulaiman, Norela; Othman, Fadzil

    2011-01-01

    A cross-section analytical study was conducted to evaluate the risk of pesticide exposure to those applying the Class II pesticides 2,4-D and paraquat in the paddy-growing areas of Kerian, Perak, Malaysia. It investigated the influence of weather on exposure as well as documented health problems commonly related to pesticide exposure. Potential inhalation and dermal exposure for 140 paddy farmers (handlers of pesticides) were assessed. Results showed that while temperature and humidity affected exposure, windspeed had the strongest impact on pesticide exposure via inhalation. However, the degree of exposure to both herbicides via inhalation was below the permissible exposure limits set by United States National Institute of Occupational Safety and Health (NIOSH). Dermal Exposure Assessment Method (DREAM) readings showed that dermal exposure with manual spraying ranged from moderate to high. With motorized sprayers, however, the level of dermal exposure ranged from low to moderate. Dermal exposure was significantly negatively correlated with the usage of protective clothing. Various types of deleterious health effects were detected among users of manual knapsack sprayers. Long-term spraying activities were positively correlated with increasing levels of the gamma-glutamyl transpeptidase (GGT) liver enzyme. The type of spraying equipment, usage of proper protective clothing and adherence to correct spraying practices were found to be the most important factors influencing the degree of pesticide exposure among those applying pesticides.

  2. Acid-base balance and cardiac index in SO2-bronchitic, papaine-emphysematous and paraquat-fibrotic rats after isoproterenol treatment.

    Science.gov (United States)

    Vértes, K; Debreczeni, L A

    1990-01-01

    SO2-bronchitis, papaine-emphysema and paraquat fibrosis were induced in Wistar rats. Blood pressure, cardiac index, total peripheral resistance, arterial blood gas values, parameters of acid-base balance were determined. Effects of 0.1 and 0.3 microgram.-1.min-1 isoproterenol iv. infusion were examined. Morphologic alterations of the lungs were verified by histopathological examinations. All the parameters investigated were found to be normal in the control rats. The treated groups differed from the normal ones: an increased blood pressure was observed in emphysema and fibrosis. A decreased cardiac index was characteristic of chronic bronchitis, high cardiac index of emphysema, high TPR of bronchitis and arterial hypoxaemy of fibrosis. The groups reacted differently to beta adrenergic stimulation: in bronchitic and fibrotic rats the cardiac index was augmented, whereas in emphysematous ones the increase proved to be smaller. The effects of isoproterenol infusion can be related to the altered beta-receptor function in the various experimental pulmonary diseases.

  3. Paraquat and Maneb Exposure Alters Rat Neural Stem Cell Proliferation by Inducing Oxidative Stress: New Insights on Pesticide-Induced Neurodevelopmental Toxicity.

    Science.gov (United States)

    Colle, Dirleise; Farina, Marcelo; Ceccatelli, Sandra; Raciti, Marilena

    2018-06-01

    Pesticide exposure has been linked to the pathogenesis of neurodevelopmental and neurodegenerative disorders including autism spectrum disorders, attention deficit/hyperactivity, and Parkinson's disease (PD). Developmental exposure to pesticides, even at low concentrations not harmful for the adult brain, can lead to neuronal loss and functional deficits. It has been shown that prenatal or early postnatal exposure to the herbicide paraquat (PQ) and the fungicide maneb (MB), alone or in combination, causes permanent toxicity in the nigrostriatal dopamine system, supporting the idea that early exposure to these pesticides may contribute to the pathophysiology of PD. However, the mechanisms mediating PQ and MB developmental neurotoxicity are not yet understood. Therefore, we investigated the neurotoxic effect of low concentrations of PQ and MB in primary cultures of rat embryonic neural stem cells (NSCs), with particular focus on cell proliferation and oxidative stress. Exposure to PQ alone or in combination with MB (PQ + MB) led to a significant decrease in cell proliferation, while the cell death rate was not affected. Consistently, PQ + MB exposure altered the expression of major genes regulating the cell cycle, namely cyclin D1, cyclin D2, Rb1, and p19. Moreover, PQ and PQ + MB exposures increased the reactive oxygen species (ROS) production that could be neutralized upon N-acetylcysteine (NAC) treatment. Notably, in the presence of NAC, Rb1 expression was normalized and a normal cell proliferation pattern could be restored. These findings suggest that exposure to PQ + MB impairs NSCs proliferation by mechanisms involving alterations in the redox state.

  4. Caenorhabditis elegans as an alternative in vivo model to determine oral uptake, nanotoxicity, and efficacy of melatonin-loaded lipid-core nanocapsules on paraquat damage.

    Science.gov (United States)

    Charão, Mariele Feiffer; Souto, Caroline; Brucker, Natália; Barth, Anelise; Jornada, Denise S; Fagundez, Daiandra; Ávila, Daiana Silva; Eifler-Lima, Vera L; Guterres, Silvia S; Pohlmann, Adriana R; Garcia, Solange Cristina

    2015-01-01

    Caenorhabditis elegans is an alternative in vivo model that is being successfully used to assess the pharmacological and toxic effects of drugs. The exponential growth of nanotechnology requires the use of alternative in vivo models to assess the toxic effects of theses nanomaterials. The use of polymeric nanocapsules has shown promising results for drug delivery. Moreover, these formulations have not been used in cases of intoxication, such as in treatment of paraquat (PQ) poisoning. Thus, the use of drugs with properties improved by nanotechnology is a promising approach to overcome the toxic effects of PQ. This research aimed to evaluate the absorption of rhodamine B-labeled melatonin (Mel)-loaded lipid-core nanocapsules (LNC) by C. elegans, the application of this model in nanotoxicology, and the protection of Mel-LNC against PQ damage. The formulations were prepared by self-assembly and characterized by particle sizing, zeta potential, drug content, and encapsulation efficiency. The results demonstrated that the formulations had narrow size distributions. Rhodamine B-labeled Mel-LNC were orally absorbed and distributed in the worms. The toxicity assessment of LNC showed a lethal dose 50% near the highest dose tested, indicating low toxicity of the nanocapsules. Moreover, pretreatment with Mel-LNC significantly increased the survival rate, reduced the reactive oxygen species, and maintained the development in C. elegans exposed to PQ compared to those worms that were either untreated or pretreated with free Mel. These results demonstrated for the first time the uptake and distribution of Mel-LNC by a nematode, and indicate that while LNC is not toxic, Mel-LNC prevents the effects of PQ poisoning. Thus, C. elegans may be an interesting alternative model to test the nanocapsules toxicity and efficacy.

  5. Standardized extracts of Bacopa monniera protect against MPP+- and paraquat-induced toxicity by modulating mitochondrial activities, proteasomal functions, and redox pathways.

    Science.gov (United States)

    Singh, Manjeet; Murthy, Ven; Ramassamy, Charles

    2012-01-01

    Parkinson's disease (PD) is one of the most common age-related neurodegenerative diseases and affects millions of people worldwide. Strong evidence supports the role of free radicals, oxidative stress, mitochondrial, and proteasomal dysfunctions underlying neuronal death in PD. Environmental factors, especially pesticides, represent one of the primary classes of neurotoxic agents associated with PD, and several epidemiological studies have identified the exposure of the herbicide paraquat (PQ) as a potential risk factor for the onset of PD. The objective of our study was to investigate the neuroprotective effects of the standardized extracts of Bacopa monniera (BM) against PQ-induced and 1-methyl-4-phenyl-pyridinium iodide (MPP(+))-induced toxicities and to elucidate the mechanisms underlying this protection. Our results show that a pretreatment with the BM extract from 50 μg/ml protected the dopaminergic SK-N-SH cell line against MPP(+)- and PQ-induced toxicities in various cell survival assays. We demonstrate that BM pretreatment prevented the depletion of glutathione (GSH) besides preserving the mitochondrial membrane potential and maintaining the mitochondrial complex I activity. BM pretreatment from 10.0 μg/ml also prevented the generation of intracellular reactive oxygen species and decreased the mitochondrial superoxide level. BM treatment activated the nuclear factor erythroid 2-related factor 2 pathway by modulating the expression of Keap1, thereby upregulating the endogenous GSH synthesis. The effect of BM on the phosphorylation of Akt further strengthens its role in the promotion of cell survival. By preserving the cellular redox homeostasis and mitochondrial activities and by promoting cell survival pathways, BM extract may have therapeutic uses in various age-related neurodegenerative diseases such as PD.

  6. Lysine acetylsalicylate increases the safety of a paraquat formulation to freshwater primary producers: A case study with the microalga Chlorella vulgaris

    International Nuclear Information System (INIS)

    Baltazar, Maria Teresa; Dinis-Oliveira, Ricardo Jorge; Martins, Alexandra; Bastos, Maria de Lourdes; Duarte, José Alberto

    2014-01-01

    Highlights: •The formulation has a reduced toxicity to C. vulgaris when compared to Gramoxone ® . •The highest protection was achieved at the proportion of 1:8 (PQ/LAS). •LAS conferred a protection of approximately 1.8 fold (% of inhibition of growth). •Salicylic acid is biotransformed by C. vulgaris after 48 h, and not detectable at 96 h. -- Abstract: Large amounts of herbicides are presently used in the industrialized nations worldwide, with an inexorable burden to the environment, especially to aquatic ecosystems. Primary producers such as microalgae are of especial concern because they are vital for the input of energy into the ecosystem and for the maintenance of oxygen in water on which most of other marine life forms depend on. The herbicide paraquat (PQ) is known to cause inhibition of photosynthesis and irreversible damage to photosynthetic organisms through generation of reactive oxygen species in a light-dependent manner. Previous studies have led to the development of a new formulation of PQ containing lysine acetylsalicylate (LAS) as an antidote, which was shown to prevent the mammalian toxicity of PQ, while maintaining the herbicidal effect. However, the safety of this formulation to primary producers in relation to commercially available PQ formulations has hitherto not been established. Therefore, the aim of this study was to evaluate the toxicity of the PQ + LAS formulation in comparison with the PQ, using Chlorella vulgaris as a test organism. Effect criterion was the inhibition of microalgal population growth. Following a 96 h exposure to increasing concentrations of PQ, C. vulgaris growth was almost completely inhibited, an effect that was significantly prevented by LAS at the proportion used in the formulation (PQ + LAS) 1:2 (mol/mol), while the highest protection was achieved at the proportion of 1:8. In conclusion, the present work demonstrated that the new formulation with PQ + LAS has a reduced toxicity to C. vulgaris when compared

  7. Activation of apoptosis signal-regulating kinase 1 is a key factor in paraquat-induced cell death: modulation by the Nrf2/Trx axis.

    Science.gov (United States)

    Niso-Santano, Mireia; González-Polo, Rosa A; Bravo-San Pedro, José M; Gómez-Sánchez, Rubén; Lastres-Becker, Isabel; Ortiz-Ortiz, Miguel A; Soler, Germán; Morán, José M; Cuadrado, Antonio; Fuentes, José M

    2010-05-15

    Although oxidative stress is fundamental to the etiopathology of Parkinson disease, the signaling molecules involved in transduction after oxidant exposure to cell death are ill-defined, thus making it difficult to identify molecular targets of therapeutic relevance. We have addressed this question in human dopaminergic neuroblastoma SH-SY5Y cells exposed to the parkinsonian toxin paraquat (PQ). This toxin elicited a dose-dependent increase in reactive oxygen species and cell death that correlated with activation of ASK1 and the stress kinases p38 and JNK. The relevance of these kinases in channeling PQ neurotoxicity was demonstrated with the use of interference RNA for ASK1 and two well-established pharmaceutical inhibitors for JNK and p38. The toxic effect of PQ was substantially attenuated by preincubation with vitamin E, blocking ASK1 pathways and preventing oxidative stress and cell death. In a search for a physiological pathway that might counterbalance PQ-induced ASK1 activation, we analyzed the role of the transcription factor Nrf2, master regulator of redox homeostasis, and its target thioredoxin (Trx), which binds and inhibits ASK1. Trx levels were undetectable in Nrf2-deficient mouse embryo fibroblasts (MEFs), whereas they were constitutively high in Keap1-deficient MEFs as well as in SH-SY5Y cells treated with sulforaphane (SFN). Consistent with these data, Nrf2-deficient MEFs were more sensitive and Keap1-deficient MEFs and SH-SY5Y cells incubated with SFN were more resistant to PQ-induced cell death. This study identifies ASK1/JNK and ASK1/p38 as two critical pathways involved in the activation of cell death under oxidative stress conditions and identifies the Nrf2/Trx axis as a new target to block these pathways and protect from oxidant exposure such as that found in Parkinson and other neurodegenerative diseases. Copyright 2010 Elsevier Inc. All rights reserved.

  8. Melatonin Improves the Photosynthetic Apparatus in Pea Leaves Stressed by Paraquat via Chlorophyll Breakdown Regulation and Its Accelerated de novo Synthesis

    Directory of Open Access Journals (Sweden)

    Katarzyna Szafrańska

    2017-05-01

    Full Text Available The positive effect of melatonin on the function of the photosynthetic apparatus is known, but little is known about the specific mechanisms of melatonin's action in plants. The influence of melatonin on chlorophyll metabolism of 24-day-old Pisum sativum L. seedlings during paraquat (PQ-induced oxidative stress was investigated in this study. Seeds were hydro-primed with water (H, 50 and 200 μM melatonin/water solutions (H-MEL50, H-MEL200, while non-primed seeds were used as controls (C. Increases in chlorophyllase activity (key enzyme in chlorophyll degradation and 5-aminolevulinic acid contents (the first compound in the porphyrin synthesis pathway were observed in H-MEL50 and H-MEL200 leaf disks. This suggests that melatonin may accelerate damaged chlorophyll breakdown and its de novo synthesis during the first hours of PQ treatment. Elevated level of pheophytin in control leaf disks following 24 h of PQ incubation probably was associated with an enhanced rate of chlorophyll degradation through formation of pheophytin as a chlorophyll derivative. This validates the hypothesis that chlorophyllide, considered for many years, as a first intermediate of chlorophyll breakdown is not. This is indicated by the almost unchanged chlorophyll to chlorophyllide ratio after 24 h of PQ treatment. However, prolonged effects of PQ-induced stress (48 h revealed extensive discolouration of control and water-treated leaf disks, while melatonin treatment alleviated PQ-induced photobleaching. Also the ratio of chlorophyll to chlorophyllide and porphyrin contents were significantly higher in plants treated with melatonin, which may indicate that this indoleamine both retards chlorophyll breakdown and stimulates its de novo synthesis during extended stress. We concluded that melatonin added into the seeds enhances the ability of pea seedlings to accelerate chlorophyll breakdown and its de novo synthesis before stress appeared and for several hours after, while

  9. Influence of diet with kale on lipid peroxides and malondialdehyde levels in blood serum of laboratory rats over intoxication with paraquat.

    Science.gov (United States)

    Sikora, Elżbieta; Bodziarczyk, Izabela

    2013-01-01

    Organism's lipid peroxidation is one of the most often examined and known physiological process evoked by free radicals. It concerns oxidation reaction of unsaturated fatty acid and/or other lipids leading to lipid oxidation products (LOP), which as a result of further changes generate among others the malondialdehyde molecules. The aim of the work was an estimation if raw or cooked kale addition to rat's diet influences antioxidant defense efficiency in their organisms in comparison to rats fed with standard AIN-93G diet. The experiment was conducted with 36 Wistar strain, male rats over 21 days. The rats were divided into 3 groups (each 12 stuck) which were fed with: standard diet AIN-93G (2 groups), AIN-93G diet with 10% addition of raw kale (2 groups), and AIN-93G with 10% addition of cooked lyophilised kale. The total content of polyphenols (FC method) and antioxidant activity (ABTS+•) were previously determined in raw and then in cooked kale. On the 20th day of experiment, half of rats (6 stuck) of each kind of the diet were injected intraperitoneally by the solution of paraquat (PQ) in physiological salt to evoke the oxidative stress. The next day animals were stunned and blood from their hearts was sampled. In the obtained serum, the levels of lipid oxidation products (LOP) and malondialdehyde (MDA) were assessed. It was observed that in blood serum of rats fed with modified diet with raw and cooked lyophilised kale addition the lipid oxides level was lower in comparison to control group fed with standard diet (p kale addition. Diet with kale, both raw and cooked, efficiently inhibited the lipid peroxidation process in rats' organisms, ongoing during natural metabolism and during evoked oxidative stress.

  10. Lysine acetylsalicylate increases the safety of a paraquat formulation to freshwater primary producers: A case study with the microalga Chlorella vulgaris

    Energy Technology Data Exchange (ETDEWEB)

    Baltazar, Maria Teresa, E-mail: mteresabaltazar@gmail.com [REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto (Portugal); IINFACTS-Institute of Research and Advanced Training in Health Sciences and Technologies, Department of Sciences, Advanced Institute of Health Sciences-North, CESPU, CRL, Rua Central de Gandra, 1317, 4585-116 Gandra (Portugal); Dinis-Oliveira, Ricardo Jorge [REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto (Portugal); IINFACTS-Institute of Research and Advanced Training in Health Sciences and Technologies, Department of Sciences, Advanced Institute of Health Sciences-North, CESPU, CRL, Rua Central de Gandra, 1317, 4585-116 Gandra (Portugal); Department of Legal Medicine and Forensic Sciences, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto (Portugal); CENCIFOR-Forensic Sciences Center, Largo da Sé Nova, 3000-213, Coimbra (Portugal); Martins, Alexandra [CIIMAR Interdisciplinary Centre of Marine and Environmental Research, Laboratory of Ecotoxicology and Ecology, Rua dos Bragas, 289, 4050-123 Porto (Portugal); ICBAS-Institute of Biomedical Sciences of Abel Salazar, University of Porto, Department of Populations Studies, Laboratory of Ecotoxicology, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto (Portugal); Bastos, Maria de Lourdes [REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, 4050-313 Porto (Portugal); Duarte, José Alberto [CIAFEL, Faculty of Sports, University of Porto, Rua Dr. Plácido Costa, 91-4200-450 Porto (Portugal); and others

    2014-01-15

    Highlights: •The formulation has a reduced toxicity to C. vulgaris when compared to Gramoxone{sup ®}. •The highest protection was achieved at the proportion of 1:8 (PQ/LAS). •LAS conferred a protection of approximately 1.8 fold (% of inhibition of growth). •Salicylic acid is biotransformed by C. vulgaris after 48 h, and not detectable at 96 h. -- Abstract: Large amounts of herbicides are presently used in the industrialized nations worldwide, with an inexorable burden to the environment, especially to aquatic ecosystems. Primary producers such as microalgae are of especial concern because they are vital for the input of energy into the ecosystem and for the maintenance of oxygen in water on which most of other marine life forms depend on. The herbicide paraquat (PQ) is known to cause inhibition of photosynthesis and irreversible damage to photosynthetic organisms through generation of reactive oxygen species in a light-dependent manner. Previous studies have led to the development of a new formulation of PQ containing lysine acetylsalicylate (LAS) as an antidote, which was shown to prevent the mammalian toxicity of PQ, while maintaining the herbicidal effect. However, the safety of this formulation to primary producers in relation to commercially available PQ formulations has hitherto not been established. Therefore, the aim of this study was to evaluate the toxicity of the PQ + LAS formulation in comparison with the PQ, using Chlorella vulgaris as a test organism. Effect criterion was the inhibition of microalgal population growth. Following a 96 h exposure to increasing concentrations of PQ, C. vulgaris growth was almost completely inhibited, an effect that was significantly prevented by LAS at the proportion used in the formulation (PQ + LAS) 1:2 (mol/mol), while the highest protection was achieved at the proportion of 1:8. In conclusion, the present work demonstrated that the new formulation with PQ + LAS has a reduced toxicity to C. vulgaris when

  11. [Intervention of pyrrolidine dithiocarbamate on expressions of connective tissue growth factor, type I collagen, and type III collage in acute paraquat poisoned rats].

    Science.gov (United States)

    Huang, Min; Yang, Hui-fang; Zhang, Ping; Chang, Xiu-li; Zhou, Zhi-jun

    2013-01-01

    To observe the changes in the expression of connective tissue growth factor (CTGF), type I collagen (Col I), and type III collagen (Col III) among the rats with acute paraquat (PQ) poisoning and the intervention effect of pyrrolidine dithiocarbamate (PDTC) on their expression, and to investigate the mechanism of PQ-induced pulmonary fibrosis and the intervention effect of PDTC on the disease. Sprague-Dawley rats were randomly divided into control group (n = 6), PQ group (n = 36), and PQ + PDTC group (n = 36). The PQ group and PQ + PDTC group were given a single dose of saline-diluted PQ (80 mg/kg) by gavage; 2 h later, the PQ + PDTC group was intraperitoneally injected with a single dose of PDTC (100 mg/kg), and the PQ group was intraperitoneally injected with the same amount of saline. The control group was given saline (1 ml/kg) by gavage and was intraperitoneally injected with the same amount of saline 2h later. At 1, 3, 7, 14, 25, and 56 days after operation, the protein expression of CTGF was evaluated by Western blot; the mRNA expression of CTGF, Col I, and Col III was analyzed by real-time quantitative PCR; the content of hydroxyproline in lung tissue was measured, and the pathological changes of lung tissue of the poisoned rats were observed. The protein expression of CTGF in the PQ group increased as the time went on, slowly from the 3rd to the 14th day and rapidly from the 28th to the 56th day, significantly higher than that in the control group at each time point (P < 0.05 or P < 0.01). The mRNA expression of CTGF in the PQ group began to rise markedly on the 1st day, increased rapidly from the 3rd to the 14th day, and remained at a relatively high level from the 28th to the 56th day, significantly higher than that in the control group at each time point (P < 0.01). The mRNA expression of Col I in the PQ group changed little on the 1st and 3rd day, increased slightly on the 7th day, and increased greatly from the 14th to the 56th day, significantly

  12. The preventive effect of vitamin C on the cellular and functional integrity of kidney cells in rats following repeated exposure to paraquat

    Directory of Open Access Journals (Sweden)

    Benjamin Nnamdi Okolonkwo

    2014-11-01

    Full Text Available Paraquat (PQ is a bipyridylium herbicide that is applied around trees in orchards and between crop rows to control broad-leaved and grassy weeds. Its oxidation results in the formation of superoxides which causes damage to cellular components. In this study, we determined the antioxidant effect vitamin C has on the cellular integrity of kidney function in rats following repeated exposure to PQ. Ninety-six male rats, grouped twelve rats per subgroup (A, Avit.c, B, Bvit.c, C, Cvit.c, D and Dvit.c were intraperitoneally injected with different sublethal increasing doses (0, 0, 2, 2, 4, 4, 6 and 6 mg/kg body weight of PQ respectively on biweekly (14 days intervals over a period of three months (84 days. Subsequently, the subgrouped animals (Avit.c, Bvit.c, Cvit.c and Dvit.c were maintained orally with 1 g/L vitamin C, while the other subgrouped animals (A, B, C and D received drinking water with negligible vitamin content throughout the study period. At the end of each monthly (28 days treatment, four animals per subgroup were selected. Urine samples were collected from each of the selected rats, after which each of the animals were anaesthetized with gaseous isoflurane and 5 mL of blood samples were collected using cardiac puncture procedure. The animals were later decapitated and their kidneys harvested. The samples collected were analyzed for urine [specific gravity (SG, pH, protein and glucose], blood (urea, creatinine, total protein and glucose, and the histological studies on kidney slides. The dose and exposure- time dependent PQ toxicity resulted in the reduction in urinary pH, elevation in urinary SG, and the detectable presence of protein and glucose in urine. It also caused marked elevation in serum urea and creatinine levels with reduction in serum protein and glucose levels and alterations in the cellular integrity of the renal architecture, especially the glomeruli and tubular tissues. Treatments on the PQ insulted animals with vitamin

  13. Synthesis and Characterization of Ru(II) Tris(1,1O-phenanthroline)-Electron Acceptor Dyads Incorporating the 4-benzoyl-N-methylpyridinium Cation or N-Benzyl-N'-methyl-viologen. Improving the Dynamic Range, Sensitivity and Response Time of Sol-Gel Based Optical Oxygen Sensors

    Science.gov (United States)

    Leventis, Nicholas; Rawashdeh, Abdel-Monen M.; Elder, Ian A.; Yang, Jinhua; Dass, Amala; Sotiriou-Leventis, Chariklia

    2004-01-01

    The title compounds (1 and 2, above) were synthesized by Sonogashira coupling reactions of appropriate Ru(1I) complexes with the electron a cceptors. Characterization was conducted in solution and in frozen ma trices. Finally, the title compounds were evaluated as dopants of sol-gel materials. It was found that the intramolecular quenching efficie ncy of 4-benzoyl-Nmethylpyridinium cation in solution depends on the solvent: photoluminescence is quenched completely in CH,CN, but not i n methanol or ethanol. On the other hand, intramolecular emission que nching by 4-benzyl-N-methyl viologen is complete in all solvents. The difference between the two quenchers is traced electrochemically to t he solvation of the 4-benzoyl-Nmethylpyridiniums by alcohol. In froze n matrices or adsorbed on the surfaces of silica aerogel, both Ru(I1) complex/electron acceptor dyads of this study are photoluminescent, and the absence of quenching has been traced to the environmental rigi dity. When doped aerogels are cooled at 77 K, the emission intensity increases by approximately 4x, and the spectra shift to the blue, analogous to what is observed with Ru(I1) complexes in solutions undergoi ng fluid-to-rigid transition. However, in contrast to frozen solution s, the luminescent moieties in the bulk of aerogels kept at low tempe ratures are still accessible to gas-phase quenchers diffusing through the mesopores, leading to more sensitive platforms for sensors than o ther room-temperature configurations. Thus the photoluminescence of o ur Ru(I1) complex dyads adsorbed on aerogel is quenchable by O2 both at room temperature and at 77 K. Furthermore, it was also found that O 2 modulates the photoluminescence of aerogels doped with 4-benzoyl -N -methylpyridinium-based dyads over a wider dynamic range compared wi th aerogels doped with either our vislogen-based dyads or with Ru(I1) tris(1,lO-phenanthroline) itself.

  14. Pulse Radiolysis of Methyl Viologen in Aqueous Solutions

    DEFF Research Database (Denmark)

    Solar, S.; Solar, W.; Getoff, N.

    1982-01-01

    dm3 mol–1 s–1, absorbs at 310 nm (ε310= 900 m2 mol–1) and 470 nm (ε470= 630 m2 mol–1) and decays by conversion into MV˙+H+ in a first-order process with k= 6 × 103 s–1. For the equilibrium MV˙+H+ MV˙++ H+ pK= 2.9 ± 0.1 was determined. The presented data explain, at least partly, the instability...

  15. Extended viologen as a source of electric oscillations

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Lubomír; Hromadová, Magdaléna; Fanelli, N.; Valášek, Michal; Kolivoška, Viliam; Gál, Miroslav

    2011-01-01

    Roč. 13, č. 10 (2011), s. 4365-4371 ISSN 1463-9076 R&D Projects: GA ČR GA203/09/0705; GA AV ČR IAA400400802; GA MŠk OC 140 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40550506 Keywords : electrochemical oscillators * electrochemistry * simple model Subject RIV: CG - Electrochemistry Impact factor: 3.573, year: 2011

  16. Electron dopable molecular wires based on the extended viologens

    Czech Academy of Sciences Publication Activity Database

    Kolivoška, Viliam; Gál, Miroslav; Pospíšil, Lubomír; Valášek, Michal; Hromadová, Magdaléna

    2011-01-01

    Roč. 13, č. 23 (2011), s. 11422-11429 ISSN 1463-9076 R&D Projects: GA ČR GA203/08/1157; GA ČR GA203/09/0705; GA AV ČR IAA400400802; GA MŠk(CZ) MEB041006 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40550506 Keywords : electron transfer * spectroelectrochemistry * molecular wires Subject RIV: CG - Electrochemistry Impact factor: 3.573, year: 2011

  17. Stochastic Resonance in Electron Transfer Oscillations of Extended Viologen

    Czech Academy of Sciences Publication Activity Database

    Hromadová, Magdaléna; Valášek, Michal; Fanelli, N.; Randriamahazaka, N.; Pospíšil, Lubomír

    2014-01-01

    Roč. 118, č. 17 (2014), s. 9066-9072 ISSN 1932-7447 R&D Projects: GA ČR GA13-19213S; GA ČR(CZ) GA14-05180S Grant - others:Rada Programu interní porpory projektů mezinárodní spolupráce AV ČR M200401202 Program:M Institutional support: RVO:61388955 ; RVO:61388963 Keywords : Circuit resonance * Harmonic analysis * Magnetic resonance Subject RIV: CG - Electrochemistry Impact factor: 4.772, year: 2014

  18. Curcumin-induced Activation of the Nrf2 Antioxidant System Attenuates Paraquat-induced InsuIin Resistance%姜黄素激活Nrf2抗氧化系统缓解百草枯诱导的胰岛素抵抗

    Institute of Scientific and Technical Information of China (English)

    杨含艳; 展平; 任丽伟; 于志文

    2015-01-01

    目的:观察姜黄素是否具有改善百草枯( paraquat,PQ)所致氧化应激诱导的胰岛素抵抗作用并探讨其改善胰岛素抵抗的效应机理。方法将实验小鼠随机分成对照组( Control组),百草枯组( PQ组)以及PQ加姜黄素组( Cur组)。 PQ和Cur组连续腹腔注射百草枯7天造模成功后。 Cur组继续Cur灌胃干预。7天后,取胰岛素敏感组织肌肉,用蛋白免疫印迹方法( Western blot,WB)检测蛋白水平和磷酸化变化,并检测脂质过氧化指标MDA。结果在PQ诱导的小鼠胰岛素抵抗模型中,姜黄素可改善小鼠葡萄糖耐量并对抗 PQ 所致的胰岛素信号蛋白 PKB-Ser473磷酸化损害;姜黄素还可明显降低肌肉MDA水平,激活小鼠Nrf2系统,促进Nrf2核转位和NQO-1的表达,同时能增强IкBα的水平,缓解氧化应激及炎症反应。结论姜黄素通过增强内源性Nrf2系统功能和胰岛素信号水平,对抗PQ诱导的氧化应激,是其缓解胰岛素抵抗的重要机理。%OBJECTIVE To examine the effect of curcumin on the paraquat-mediated oxidative stress and insu-lin resistance ,and to further explore the working mechanism underlying its effect .METHODS Thirty mice were randomly divided into 3 groups:control group , paraquat group and curcumin intervention group .Paraquat group and curcumin intervention group were continuously intraperitoneal injection of paraquat for 7 days to induce the models of insulin resistance.The curcumin intervention group was continuously gavaged with curcumin for another 7 days.Then,all mice were euthanized for muscle collection .The protein and phosphorylation levels in muscle tissue were examed by Western blot and the content of malonaldchyde ( MDA) indicated for lipid peroxidation was deter-mined.Results Curcumin improved the glucose tolerance in paraquat-induced insulin resistance in mice together with attenuation of PQ-caused impairment in PKBSer473

  19. Curcumin-induced Activation of the Nrf2 Antioxidant System Attenuates Paraquat-induced InsuIin Resistance%姜黄素激活Nrf2抗氧化系统缓解百草枯诱导的胰岛素抵抗

    Institute of Scientific and Technical Information of China (English)

    杨含艳; 展平; 任丽伟; 于志文

    2015-01-01

    目的:观察姜黄素是否具有改善百草枯( Paraquat,PQ)所致氧化应激诱导的胰岛素抵抗作用并探讨其改善胰岛素抵抗的效应机理。方法将实验小鼠随机分成对照组( Control组),百草枯组( PQ组)以及PQ加姜黄素组( Cur组)。 PQ和Cur组连续腹腔注射百草枯7天造模成功后。 Cur组继续Cur灌胃干预。7天后,取胰岛素敏感组织肌肉,用蛋白免疫印迹方法( Western blot,WB)检测蛋白水平和磷酸化变化,并检测脂质过氧化指标MDA。结果在PQ诱导的小鼠胰岛素抵抗模型中,姜黄素可改善小鼠葡萄糖耐量并对抗 PQ 所致的胰岛素信号蛋白 PKB-Ser473磷酸化损害;姜黄素还可明显降低肌肉MDA水平,激活小鼠Nrf2系统,促进Nrf2核转位和NQO-1的表达,同时能增强IкBα的水平,缓解氧化应激及炎症反应。结论姜黄素通过增强内源性Nrf2系统功能和胰岛素信号水平,对抗PQ诱导的氧化应激,是其缓解胰岛素抵抗的重要机理。%OBJECTIVE To observe the effect and explore the mechanism of curcumin on the paraquat-media-ted oxidative stress and insulin resistance.METHODS Thirty mice were randomly divided into 3 groups:control group,paraquat group and curcumin intervention group.Paraquat group and curcumin intervention group were contin-uously intraperitoneal injection of paraquat for 7 days to induce the models of insulin resistance.The curcumin inter-vention group was continuously gavaged with curcumin for another 7 days.Then,all mice were euthanized for muscle collection.The protein and phosphorylation levels in muscle tissue were examed by Western blot and the content of malonaldchyde ( MDA) indicated for lipid peroxidation was determined.RESULTS Curcumin improved the glucose tolerance in paraquat-induced insulin resistance in mice together with attenuation of PQ-caused impairment in PKB-Ser473 phosphorylation.Curcumin also significantly reduced

  20. RESEARCH NOTE EFFECTIVENESS OF PARAQUAT ON THE ...

    African Journals Online (AJOL)

    The remaining area received no chemical treatment and the grass was left to die at first frost (May l0). Thirty Africander cross Sussex steers, approxi- mately l0 rnonths of age, were randomly allocated to the 2 treatments. From July 20 until September 28. (70 days), both treatment areas were grazed by the respective groups.

  1. 3,3′-Di-n-butyl-1,1′-(p-phenylenedimethylenediimidazolium bis(hexafluorophosphate

    Directory of Open Access Journals (Sweden)

    Rosenani A. Haque

    2010-04-01

    Full Text Available The asymmetric unit of the title N-heterocyclic carbene compound, C22H32N42+·2PF6−, consists of one half of the N-heterocyclic carbene dication and one hexafluorophosphate anion. The dication lies across a crystallographic inversion center. The imidazole ring is twisted away from the central benzene ring, making a dihedral angle of 76.23 (6°. The hexafluorophosphate anions link the cations into a three-dimensional network via intermolecular C—H...F hydrogen bonds. A weak C—H...π interaction further stabilizes the crystal structure.

  2. Improved radical stability of viologen anolytes in aqueous organic redox flow batteries.

    Science.gov (United States)

    Hu, Bo; Tang, Yijie; Luo, Jian; Grove, Grant; Guo, Yisong; Liu, T Leo

    2018-05-09

    A high voltage (1.38 V) total organic aqueous redox flow battery is reported using 1,1'-bis[3-(trimethylammonio)propyl]-4,4'-bipyridinium tetrachloride ((NPr)2V) as an anolyte and 4-trimethylammonium-TEMPO chloride (NMe-TEMPO) as a catholyte. The exceptional radical stability of [(NPr)2V]+˙ enabled the flow battery in achieving 97.48% capacity retention for 500 cycles and a power density of 128.2 mW cm-2.

  3. Reactivity of OH and O– with aqueous methyl viologen studied by pulse radiolysis

    DEFF Research Database (Denmark)

    Solar, Sonja; Solar, Wolfgang; Getoff, Nikola

    1985-01-01

    The behaviour of aqueous MV2+ towards oxidizing radicals (OH and O–) has been investigated in the pH range from 6 to 14 by means of pulse radiolysis. A semi-linear optimization method was applied for resolving the complex reaction mechanism. In the pH range from 6 to 8 the rate constant for attac...

  4. 40 CFR 180.205 - Paraquat; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... the bis(methyl sulfate) or the dichloride salt (both calculated as the cation) in or on the following..., kidney 0.5 Hog, meat 0.05 Hog, meat byproducts, except kidney 0.05 Hop, dried cones 0.5 Horse, fat 0.05 Horse, kidney 0.5 Horse, meat 0.05 Horse, meat byproducts, except kidney 0.05 Kiwifruit 0.05 Lentil...

  5. Survival predictors in paraquat intoxification and role of immunosuppression

    Directory of Open Access Journals (Sweden)

    Keng-Hee Koh

    2014-01-01

    In contrast, there was no difference in survival with immunosuppression regime (38 out of 64 patients (59.4% compared to historical control (30 out of 52 patients (57.7% (p = 0.885 in those with eGFR > 50 ml/min/1.73 m2 or WBC 11,000/μL.

  6. CCDC 997386: Experimental Crystal Structure Determination : 1,1'-methylenebis(3-(2-furyl)-1H-imidazol-3-ium) bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Rieb, Julia; Raba, Andreas; Haslinger, Stefan; Kaspar, Manuel; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  7. Rapid small intestinal permeability assay based on riboflavin and lactulose detected by bis-boronic acid appended benzyl viologens.

    Science.gov (United States)

    Resendez, Angel; Abdul Halim, Md; Landhage, Caroline M; Hellström, Per M; Singaram, Bakthan; Webb, Dominic-Luc

    2015-01-15

    Although organoboronic acids are efficient high-throughput sugar sensors, they have not been pursued for gut permeability studies. A modification of the lactulose/mannitol assay is described by which small intestinal permeability is assessed at the time of urine collection using a lactulose/riboflavin ratio. Volunteers ingested 50mg riboflavin and either 5 g mannitol or 10 g lactulose. Urine was collected for 6 hrs. Riboflavin was assayed by autofluorescence. Riboflavin was removed by C18 solid phase extraction. Lactulose and mannitol were then assayed using 1,1'-bis(2-boronobenzyl)-4,4'-bipyridinium (4,4'oBBV) coupled to the fluorophore HPTS. The temporal profile over 6 hrs for riboflavin paralleled mannitol. Riboflavin recovery in urine was 11.1 ± 1.9 % (mean ± SEM, n=7), similar to mannitol. There was selective binding of 4,4'oBBV to lactulose, likely involving cooperativity between the fructose and galactose moieties. Lower limits of detection and quantification were 90 and 364 μM. The lactulose assay was insensitive to other permeability probes (e.g., sucrose, sucralose) while tolerating glucose or lactose. This assay can be adapted to automated systems. Stability of 4,4'oBBV exceeds 4 years. Riboflavin measured by autofluorescence combined with lactulose measured with 4,4'oBBV represents a useful new chemistry for rapid measurement of intestinal permeability with excellent stability, cost and throughput benefits. Copyright © 2014. Published by Elsevier B.V.

  8. An Investigation of Methyl Viologen Functionalized Reduced Graphene Oxide: Chitosan as a Support for Pt Nanoparticles Towards Ethanol Electrooxidation

    Science.gov (United States)

    Ekrami-Kakhki, Mehri-Saddat; Farzaneh, Nahid; Abbasi, Sedigheh; Beitollahi, Hadi; Ekrami-Kakhki, Seyed Ali

    2018-05-01

    In this research, graphene oxide was prepared by a modified Hummers' method, and then functionalized with 1, 1'-dimethyl-4, 4'-bipyridinium dichloride (MV), and chitosan (CH) to get a MV-RGO-CH support. Pt nanoparticles were prepared on this support to get Pt/MV-RGO-CH catalyst. The morphology and microstructure of Pt/MV-RGO-CH catalyst were characterized with transmission electron microscopy image and X-ray diffraction analysis. The electrocatalytic activity of the prepared catalyst towards ethanol oxidation was investigated by carbon monoxide stripping voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy techniques. The effects of some experimental parameters such as scan rate, ethanol concentration, and temperature were investigated for ethanol electrooxidation at Pt/MV-RGO-CH catalyst. Durability of the catalyst was also investigated. The electrocatalytic performance of Pt/MV-RGO-CH catalyst for ethanol oxidation was compared with those of Pt/CH and Pt/MV-RGO catalysts. The higher electrocatalytic performance of Pt/MV-RGO-CH than Pt/CH and Pt/MV-RGO catalysts towards ethanol electrooxidation indicated that Pt/MV-RGO-CH could be a promising catalyst for application in direct ethanol fuel cells.

  9. Radically enhanced molecular recognition

    KAUST Repository

    Trabolsi, Ali; Khashab, Niveen M.; Fahrenbach, Albert C.; Friedman, Douglas C.; Colvin, Michael T.; Coti, Karla K.; Bení tez, Diego S.; Tkatchouk, Ekaterina; Olsen, John Carl; Belowich, Matthew E.; Carmieli, Raanan; Khatib, Hussam A.; Goddard, William Andrew III; Wasielewski, Michael R.; Stoddart, Fraser Fraser Raser

    2009-01-01

    The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host-guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication. © 2010 Macmillan Publishers Limited. All rights reserved.

  10. Radically enhanced molecular recognition

    KAUST Repository

    Trabolsi, Ali

    2009-12-17

    The tendency for viologen radical cations to dimerize has been harnessed to establish a recognition motif based on their ability to form extremely strong inclusion complexes with cyclobis(paraquat-p-phenylene) in its diradical dicationic redox state. This previously unreported complex involving three bipyridinium cation radicals increases the versatility of host-guest chemistry, extending its practice beyond the traditional reliance on neutral and charged guests and hosts. In particular, transporting the concept of radical dimerization into the field of mechanically interlocked molecules introduces a higher level of control within molecular switches and machines. Herein, we report that bistable and tristable [2]rotaxanes can be switched by altering electrochemical potentials. In a tristable [2]rotaxane composed of a cyclobis(paraquat-p-phenylene) ring and a dumbbell with tetrathiafulvalene, dioxynaphthalene and bipyridinium recognition sites, the position of the ring can be switched. On oxidation, it moves from the tetrathiafulvalene to the dioxynaphthalene, and on reduction, to the bipyridinium radical cation, provided the ring is also reduced simultaneously to the diradical dication. © 2010 Macmillan Publishers Limited. All rights reserved.

  11. CCDC 1407688: Experimental Crystal Structure Determination : (mu2-1,1'-ethane-1,2-diylbis(3-methyl-2,3-dihydro-1H-imidazol-2-ylidene))-di-gold bis(hexafluorophosphate)

    KAUST Repository

    Baron, Marco; Tubaro, Cristina; Basato, Marino; Isse, Abdirisak Ahmed; Gennaro, Armando; Cavallo, Luigi; Graiff, Claudia; Dolmella, Alessandro; Falivene, Laura; Caporaso, Lucia

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  12. CCDC 1408064: Experimental Crystal Structure Determination : (mu2-1,1'-methylenebis(3-methyl-2,3-dihydro-1H-imidazol-2-ylidene))-bis(iodo)-di-gold bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Baron, Marco; Tubaro, Cristina; Basato, Marino; Isse, Abdirisak Ahmed; Gennaro, Armando; Cavallo, Luigi; Graiff, Claudia; Dolmella, Alessandro; Falivene, Laura; Caporaso, Lucia

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  13. CCDC 1420289: Experimental Crystal Structure Determination : (2,2'-(methylenebis(1H-imidazol-2-ylidene-3,1(2H)-diylmethylene))dipyridine)-tris(acetonitrile)-iron bis(hexafluorophosphate) diethyl ether solvate

    KAUST Repository

    Weiss, Daniel T.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  14. CCDC 1448761: Experimental Crystal Structure Determination : (mu2-1,1'-methylenebis(3-methyl-2,3-dihydro-1H-imidazol-2-ylidene))-tetrachloro-di-gold bis(hexafluorophosphate)

    KAUST Repository

    Baron, Marco; Tubaro, Cristina; Basato, Marino; Isse, Abdirisak Ahmed; Gennaro, Armando; Cavallo, Luigi; Graiff, Claudia; Dolmella, Alessandro; Falivene, Laura; Caporaso, Lucia

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  15. CCDC 997388: Experimental Crystal Structure Determination : (1,1'-methylenebis(3-(2-thienyl)-2,3-dihydro-1H-imidazol-2-ylidene))-tetrakis(acetonitrile)-iron(ii) bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Rieb, Julia; Raba, Andreas; Haslinger, Stefan; Kaspar, Manuel; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  16. CCDC 997389: Experimental Crystal Structure Determination : bis(1,1'-methylenebis(3-(2-furyl)-2,3-dihydro-1H-imidazol-2-ylidene))-bis(acetonitrile)-iron(ii) bis(hexafluorophosphate) acetone solvate

    KAUST Repository

    Rieb, Julia; Raba, Andreas; Haslinger, Stefan; Kaspar, Manuel; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  17. CCDC 997387: Experimental Crystal Structure Determination : (1,1'-methylenebis(3-(2-furyl)-2,3-dihydro-1H-imidazol-2-ylidene))-tetrakis(acetonitrile)-iron(ii) bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Rieb, Julia; Raba, Andreas; Haslinger, Stefan; Kaspar, Manuel; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  18. CCDC 835523: Experimental Crystal Structure Determination : bis(mu~2~-1,1'-propane-1,3-diylbis(3-methyl-2,3-dihydro-1H-imidazol-2-ylidene))-di-gold (ii) bis(hexafluorophosphate)

    KAUST Repository

    Baron, M.; Tubaro, C.; Biffis, A.; Basato, M.; Graiff, C.; Poater, A.; Cavallo, Luigi; Armaroli, N.; Accorsi, G.

    2012-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  19. CCDC 1420290: Experimental Crystal Structure Determination : (6,6'-bis((3-methyl-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)methyl)-2,2'-bipyridine)-bis(acetonitrile)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Weiss, Daniel T.; Anneser, Markus R.; Haslinger, Stefan; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  20. CCDC 855138: Experimental Crystal Structure Determination : bis(mu~2~-1,1'-propane-1,3-diylbis(3-methyl-2,3-dihydro-1H-imidazol-2-ylidene))-di-gold (ii) bis(hexafluorophosphate)

    KAUST Repository

    Baron, M.

    2012-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  1. CCDC 992646: Experimental Crystal Structure Determination : (1,1'-methanediylbis(3-(pyridin-2-yl)-2,3-dihydro-1H-imidazol-2-ylidene))-bis(methyl isonicotinate)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Haslinger, Stefan

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  2. CCDC 992643: Experimental Crystal Structure Determination : (1,1'-methanediylbis(3-(pyridin-2-yl)-2,3-dihydro-1H-imidazol-2-ylidene))-bis(trimethylphosphino)-iron bis(hexafluorophosphate)

    KAUST Repository

    Haslinger, Stefan

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  3. CCDC 992645: Experimental Crystal Structure Determination : (1,1'-methanediylbis(3-(pyridin-2-yl)-2,3-dihydro-1H-imidazol-2-ylidene))-bis(pyridine)-iron bis(hexafluorophosphate)

    KAUST Repository

    Haslinger, Stefan

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  4. CCDC 992644: Experimental Crystal Structure Determination : (1,1'-methanediylbis(3-(pyridin-2-yl)-2,3-dihydro-1H-imidazol-2-ylidene))-bis(N,N-dimethylpyridin-4-amine)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Haslinger, Stefan; Kü ck, Jens W.; Hahn, Eva M.; Cokoja, Mirza; Pö thig, Alexander; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  5. Effets combinés du compost, du Paraquat et de la ...

    African Journals Online (AJOL)

    Ce-PC

    1Laboratoire Sol-Eau-Plante, Institut de l'Environnement et de Recherches Agricoles (INERA),. Ouagadougou, 01 BP 476 Ouagadougou 01, Burkina Faso. 2Laboratoire d'Etude et de Recherche sur la Fertilité des Sols (LERF), Université Nazi Boni (UNB),. Bobo-Dioulasso, 01 BP. 1091 Bobo-Dioulasso 01, Burkina Faso.

  6. Mortality Analysis of Patients with Paraquat Poisoning Treated at Two University Hospitals in Shiraz, Iran

    Directory of Open Access Journals (Sweden)

    Fazel Goudarzi

    2014-12-01

    Conlcusion: PQ poisoning is associated with high mortality requiring an immediate assessment of patients and prediction of prognosis. Renal and hepatic failure in addition to respiratory distress can be the strongest risk factors for poor prognosis in acute PQ poisoning.

  7. The zinc finger protein ZAT11 modulates paraquat-induced programmed cell death in Arabidopsis thaliana

    NARCIS (Netherlands)

    Qureshi, Muhammad Kamran; Sujeeth, Neerakkal; Gechev, Tsanko S.; Hille, Jacques

    Plants use programmed cell death (PCD) as a tool in their growth and development. PCD is also involved in defense against different kinds of stresses including pathogen attack. In both types of PCD, reactive oxygen species (ROS) play an important role. ROS is not only a toxic by-product but also

  8. One-electron reduction of an "extended viologen" p-phenyle-bis-4,4´-(aryl-2,6-diphenylpyridinium) dication

    Czech Academy of Sciences Publication Activity Database

    Funston, A.; Kirby, J. P.; Miller, J. R.; Pospíšil, Lubomír; Fiedler, Jan; Hromadová, Magdaléna; Gál, Miroslav; Pecka, J.; Valášek, M.; Zawada, Z.; Rempala, P.; Michl, J.

    2005-01-01

    Roč. 109, č. 48 (2005), s. 10862-10869 ISSN 1089-5639 R&D Projects: GA ČR GA203/04/0921; GA ČR GA203/03/0821; GA AV ČR IAA400400505; GA MŠk LC510 Grant - others:Office of Basic Energy Sciences(US) DE-AC02-98-CH10886; U.S. National Science Foundation(US) CHE-0446688 Institutional research plan: CEZ:AV0Z40400503 Keywords : molecular electronics * electrochemistry * redox titration * UV-visible Subject RIV: CG - Electrochemistry Impact factor: 2.898, year: 2005

  9. Rate dependence of electron transfer on donor-acceptor separation and on free enthalpy change. The Ru(bpy)32+/viologen2+ system

    International Nuclear Information System (INIS)

    Rau, H.; Frank, R.; Greiner, G.

    1986-01-01

    By attachment of hydrocarbon chains of different lengths to the bipyridyl ligands in Ru(bpy) 3 2+ we have adjusted the donor-acceptor separation in the electron-transfer system Ru[(C/sub n/H/sub 2n+1/) 2 bpyl 3 2+ /methylviolgen. Two electron-transfer reactions with different ΔG are investigated in fluid solution: the quenching of the excited complexes by methylviologen (MV 2+ ) which is exergonic with -0.4 eV and the thermal back electron transfer which is exergonic with -1.7 eV. We observe an exponential decrease of the quenching rate on distance. The back electron transfer is independent of donor-acceptor separation; electron transfer is found to take place at distances of 1.5 nm and more. The results are discussed in terms of a hypothesis on the interdependence of transfer distance and free enthalpy change and compared with current theories. In the framework of the simple classical Marcus model, the Marcus equation relating transfer rate and free enthalpy change is transposed into the Rehm-Weller equation by simple mathematical manipulations and the implications of this are discussed

  10. Capacidade antioxidante da microalga Spirulina platensis em células da levedura Saccharomyces cerevisiae submetidas ao estressor paraquat

    OpenAIRE

    Guarienti, Cíntia; Bertolin, Telma Elita; Costa, Jorge Alberto Vieira

    2010-01-01

    Em virtude de várias publicações terem mostrado a alta associação entre a geração de radicais livres e as doenças crônico-degenerativas, tem havido grande interesse por alimentos funcionais antioxidantes. O excesso de espécies reativas no organismo resulta em estresse oxidativo que provoca danos celulares e teciduais. A microalga Spirulina tem sido pesquisada em função de suas propriedades nutricionais e antioxidantes. O objetivo desse trabalho foi de avaliar a atividade antioxidante da mi...

  11. Simultaneous Voltammetric Detection of Carbaryl and Paraquat Pesticides on Graphene-Modified Boron-Doped Diamond Electrode

    NARCIS (Netherlands)

    Pop, Aniela; Manea, Florica; Flueras, Adriana; Schoonman, J.

    2017-01-01

    Monitoring of pesticide residues in food, beverages, and the environment requires fast, versatile, and sensitive analyzing methods. Direct electrochemical detection of pesticides could represent an efficient solution. Adequate electrode material, electrochemical technique, and optimal operation

  12. CCDC 1420288: Experimental Crystal Structure Determination : bis(acetonitrile)-(1-((2,2'-bipyridin-6-yl)methyl)-3-((pyridin-2-yl)methyl)-2,3-dihydro-1H-imidazol-2-ylidene)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Weiss, Daniel T.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  13. CCDC 1036601: Experimental Crystal Structure Determination : bis(dimethyl sulfoxide)-(1,3,6,8,11,13,16,18-octaazapentacyclo[16.2.1.13,6.18,11.113,16]tetracosa-4,9,14,19-tetraene-21,22,23,24-tetraylidene)-iron bis(hexafluorophosphate) dimethyl sulfoxide solvate

    KAUST Repository

    Anneser, Markus R.; Haslinger, Stefan; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  14. CCDC 1036603: Experimental Crystal Structure Determination : (nitrosyl)-(1,3,6,8,11,13,16,18-octaazapentacyclo[16.2.1.13,6.18,11.113,16]tetracosa-4,9,14,19-tetraene-21,22,23,24-tetraylidene)-iron(iii) bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Anneser, Markus R.; Haslinger, Stefan; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  15. CCDC 1036602: Experimental Crystal Structure Determination : dicarbonyl-(1,3,6,8,11,13,16,18-octaazapentacyclo[16.2.1.13,6.18,11.113,16]tetracosa-4,9,14,19-tetraene-21,22,23,24-tetraylidene)-iron bis(hexafluorophosphate)

    KAUST Repository

    Anneser, Markus R.; Haslinger, Stefan; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  16. CCDC 1420291: Experimental Crystal Structure Determination : (2-(3-((3-((3-methyl-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)methyl)-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)methyl)-2,3-dihydro-1H-imidazol-2-ylidene-1-yl)pyridine)-bis(acetonitrile)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Weiss, Daniel T.; Anneser, Markus R.; Haslinger, Stefan; Pö thig, Alexander; Cokoja, Mirza; Basset, Jean-Marie; Kü hn, Fritz E.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  17. CCDC 963848: Experimental Crystal Structure Determination : bis(acetonitrile)-(1,3,6,8,11,13,16,18-octaazapentacyclo[16.2.1.13,6.18,11.113,16]tetracosa-4,9,14,19-tetraene-21,22,23,24-tetraylidene)-iron bis(hexafluorophosphate) acetonitrile solvate

    KAUST Repository

    Anneser, Markus R.

    2015-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  18. HOLOGRAPHIC GRATING RECORDING IN “LYOTROPIC LIQUID CRYSTAL – VIOLOGEN” SYSTEM

    Directory of Open Access Journals (Sweden)

    Hanna Bordyuh

    2013-12-01

    Full Text Available This work presents the results of nonlinear optical experiment run on the samples of lyotropic liquid crystal (LLC with viologen admixtures. During the experiment we obtained dynamic grating recording on bilayered LLC-viologen samples and determined main characteristics of recoded gratings. It was found out that the recording takes place in a thin near-cathode coloured viologen layer. The analysis of kinetics of thermal gratings erasing showed that contribution of a thermal nonlinearity into general diffraction efficiency is negligible small. The last fact is connected with a separation of LLC-viologen samples under the action of an electric field and heat sink into the liquid crystal layer

  19. Activation of apoptosis signal-regulating kinase 1 is a key factor in paraquat-induced cell death : modulation by the Nrf2/Trx axis

    NARCIS (Netherlands)

    Niso-Santano, Mireia; González-Polo, Rosa A; Bravo-San Pedro, José M; Gómez-Sánchez, Rubén; Lastres-Becker, Isabel; Ortiz-Ortiz, Miguel A; Soler, Germán; Morán, José M; Cuadrado, Antonio; Fuentes, José M

    2010-01-01

    Although oxidative stress is fundamental to the etiopathology of Parkinson disease, the signaling molecules involved in transduction after oxidant exposure to cell death are ill-defined, thus making it difficult to identify molecular targets of therapeutic relevance. We have addressed this question

  20. Proteomics of the oxidative stress response induced by hydrogen peroxide and paraquat reveals a novel AhpC-like protein in Pseudomonas aeruginosa

    DEFF Research Database (Denmark)

    Hare, Nathan J; Scott, Nichollas E; Shin, Eun Hye H

    2011-01-01

    hypothetical antioxidant protein (PA3450) that shares sequence similarity with 1-Cys peroxiredoxins. Other induced proteins included known oxidative stress proteins (superoxide dismutase and catalase), as well as those involved in iron acquisition (siderophore biosynthesis and receptor proteins FpvA and Fpt...

  1. Effect of vitamin C on N,N′-dimethyl-4,4′-bipyridinium dichloride ...

    African Journals Online (AJOL)

    Purpose: To evaluate the effectiveness of vitamin C on paraquat-induced hepatic and renal toxicity in Swiss albino mice. Methods: Three groups of Swiss albino mice (n = 10), i.e., control, paraquat (15 mg/kg) and paraquat (15 mg/kg) + vitamin C (20 mg/kg) were used in the study. The drugs were administered ...

  2. Synthesis and Photophysical and Electrochemical Properties of Functionalized Mono-, Bis-, and Trisanthracenyl Bridged Ru(II Bis(2,2′:6′,2″-terpyridine Charge Transfer Complexes

    Directory of Open Access Journals (Sweden)

    Adewale O. Adeloye

    2014-01-01

    Full Text Available With the aim of developing new molecular devices having long-range electron transfer in artificial systems and as photosensitizers, a series of homoleptic ruthenium(II bisterpyridine complexes bearing one to three anthracenyl units sandwiched between terpyridine and 2-methyl-2-butenoic acid group are synthesized and characterized. The complexes formulated as bis-4′-(9-monoanthracenyl-10-(2-methyl-2-butenoic acid terpyridyl ruthenium(II bis(hexafluorophosphate (RBT1, bis-4′-(9-dianthracenyl-10-(2-methyl-2-butenoic acid terpyridyl ruthenium(II bis(hexafluorophosphate (RBT2, and bis-4′-(9-trianthracenyl-10-(2-methyl-2-butenoic acid terpyridyl ruthenium(II bis(hexafluorophosphate (RBT3 were characterized by elemental analysis, FT-IR, UV-Vis, photoluminescence, 1H and 13C NMR spectroscopy, and electrochemical techniques by elemental analysis, FT-IR, UV-Vis, photoluminescence, 1H and 13C NMR spectroscopy, and electrochemical techniques. The cyclic voltammograms (CVs of (RBT1, (RBT2, and (RBT3 display reversible one-electron oxidation processes at E1/2 = 1.13 V, 0.71 V, and 0.99 V, respectively (versus Ag/AgCl. Based on a general linear correlation between increase in the length of π-conjugation bond and the molar extinction coefficients, the Ru(II bisterpyridyl complexes show characteristic broad and intense metal-to-ligand charge transfer (MLCT band absorption transitions between 480–600 nm, ε=9.45×103 M−1 cm−1, and appreciable photoluminescence spanning the visible region.

  3. Absence of sodA Increases the Levels of Oxidation of Key Metabolic Determinants of Borrelia burgdorferi.

    Directory of Open Access Journals (Sweden)

    Maria D Esteve-Gassent

    Full Text Available Borrelia burgdorferi, the causative agent of Lyme disease, alters its gene expression in response to environmental signals unique to its tick vector or vertebrate hosts. B. burgdorferi carries one superoxide dismutase gene (sodA capable of controlling intracellular superoxide levels. Previously, sodA was shown to be essential for infection of B. burgdorferi in the C3H/HeN model of Lyme disease. We employed two-dimensional electrophoresis (2-DE and immunoblot analysis with antibodies specific to carbonylated proteins to identify targets that were differentially oxidized in the soluble fractions of the sodA mutant compared to its isogenic parental control strain following treatment with an endogenous superoxide generator, methyl viologen (MV, paraquat. HPLC-ESI-MS/MS analysis of oxidized proteins revealed that several proteins of the glycolytic pathway (BB0057, BB0020, BB0348 exhibited increased carbonylation in the sodA mutant treated with MV. Levels of ATP and NAD/NADH were reduced in the sodA mutant compared with the parental strain following treatment with MV and could be attributed to increased levels of oxidation of proteins of the glycolytic pathway. In addition, a chaperone, HtpG (BB0560, and outer surface protein A (OspA, BBA15 were also observed to be oxidized in the sodA mutant. Immunoblot analysis revealed reduced levels of Outer surface protein C (OspC, Decorin binding protein A (DbpA, fibronectin binding protein (BBK32, RpoS and BosR in the sodA mutant compared to the control strains. Viable sodA mutant spirochetes could not be recovered from both gp91/phox-⁄- and iNOS deficient mice while borrelial DNA was detected in multiple tissues samples from infected mice at significantly lower levels compared to the parental strain. Taken together, these observations indicate that the increased oxidation of select borrelial determinants and reduced levels of critical pathogenesis-associated lipoproteins contribute to the in vivo deficit of

  4. Electrochemical studies of redox probes in self-organized lyotropic ...

    Indian Academy of Sciences (India)

    Administrator

    quinone|hydroquinone, methyl viologen and ferrocenemethanol probes in a lyotropic hexagonal columnar phase (H1 phase) using cyclic voltammetry and electrochemical impedance ..... hydrogen bond of hydroquinone during oxidation is.

  5. Using Paraquat to Generate Anion Free Radicals and Hydrogen Peroxide in "In Vitro": Antioxidant Effect of Vitamin E--A Procedure to Teach Theoretical and Experimental Principles of Reactive Oxygen Species Biochemistry

    Science.gov (United States)

    Jimenez-Del-Rio, Marlene; Suarez-Cedeno, Gerson; Velez-Pardo, Carlos

    2010-01-01

    The theoretical basis of reactive oxygen species and their impact on health issues are relatively easy to understand by biomedical students. The detection of reactive oxygen species requires expensive equipment, the procedures are time consuming and costly, and the results are hard to interpret. Moreover, cause-and-effect relationships in the…

  6. Anaerobic Aryl Reductive Dehalogenation of Halobenzoates by Cell Extracts of “Desulfomonile tiedjei”

    OpenAIRE

    DeWeerd, Kim A.; Suflita, Joseph M.

    1990-01-01

    We studied the transformation of halogenated benzoates by cell extracts of a dehalogenating anaerobe, “Desulfomonile tiedjei.” We found that cell extracts possessed aryl reductive dehalogenation activity. The activity was heat labile and dependent on the addition of reduced methyl viologen, but not on that of reduced NAD, NADP, flavin mononucleotide, flavin adenine dinucleotide, desulfoviridin, cytochrome c3, or benzyl viologen. Dehalogenation activity in extracts was stimulated by formate, C...

  7. Sierra Leone Journal of Biomedical Research Vol. 2 (1) pp. 54-64 ...

    African Journals Online (AJOL)

    2010-06-04

    Jun 4, 2010 ... with the degree of poisoning dependant on the route of ... credited to its ability to bind the excess copper. (II) (Cu2+) ions .... intraperitoneal dose of normal saline, paraquat only (10 ...... Mechanism of Paraquat Toxicity in Lung ...

  8. 40 CFR 152.175 - Pesticides classified for restricted use.

    Science.gov (United States)

    2010-07-01

    ...% and less All uses (domestic and nondomestic) Unclassified Paraquat (dichloride) and paraquat bis... subsoil ......do Do. ......do All subsoil uses Unclassified Sulfotepp Sprays and smoke generators All uses Restricted Inhalation hazard to humans. Zinc Phosphide All formulations 2% and less All domestic uses and non...

  9. Intracellular and extracellular radiosensitization of Serratia marcescens by bipyridinium compounds

    International Nuclear Information System (INIS)

    Anderson, R.F.; Patel, K.B.

    1979-01-01

    The one-electron reduced form of the bipyridinium compounds benzylviologen and methylviologen have been found to diffuse across the cytoplasmic membrane of Serratia marcescens cells. Subsequent reoxidation of the viologens to the dicationic form traps the compound inside the cells. Cells at a density of 4 x 10 9 ml -1 took up approximately half of the compound when incubated with an initial extracellular concentration of 200μM of either reduced viologen. The degree of radiosensitization in anoxia afforded by the compounds parallels the rise in internal concentration and reaches a maximum enhancement ratio of 2.0 +- 0.1 for both compounds. This level in sensitization is similar to that found when the compounds are external to the cell. No additivity in sensitization is found when the viologens are both internal and external to the cells at the time of irradiation suggesting that the same target site is sensitized. This site is probably some membrane-associated structure

  10. 78 FR 57379 - Cancellation of Pesticides for Non-Payment of Year 2013 Registration Maintenance Fees

    Science.gov (United States)

    2013-09-18

    ...-00002 7618 039959-00003 7619 040391-00003 Entech Fog-5 040510-00003 Water Purification Tablets, Iodine...-00001 Paraquat 3SL Herbicide 083030-00001 Citrex 083403-00001 Bactiguard Air Filters 083742-00002 Pond...

  11. EFFECT OF PESTICIDES ON RAT (Rattus norvegicus ERYTHROCYTES ANTIOXIDANT ENZYMES IN VITRO

    Directory of Open Access Journals (Sweden)

    Jasna Friščić

    2014-10-01

    Full Text Available Abstract: In the last century, maximum in herbicide production was achieved. Growing use of herbicides initiated the need for continuous evaluation of damaging effects of herbicides on human health and environment. Paraquat is the trade name for N,N′-dimethyl-4,4′-bipyridinium dichloride and one of the most widely used herbicides in the world. Although mechanism of paraquat toxicity remains undefined, a great portion of toxicity is attributed to the process of redox cycling. In this research, rat erythrocytes were exposed to various paraquat concentrations (0, 0.25, 0.5, 0.75, 1.25 mM. Changes in antioxidant enzymes activity, catalase and superoxide dismutase were determined, and also the activity of erythrocyte acetylcholinesterase. Obtained results show damaging effects of paraquat on erythrocytes due to oxidative stress.

  12. bipyridinium dichloride-induced hepatic and renal toxicity in Swiss

    African Journals Online (AJOL)

    Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, 300001 Nigeria. ... Methods: Three groups of Swiss albino mice (n = 10), i.e., control, paraquat (15 mg/kg) ... Control and vitamin C-treated mice .... Tokyo, Japan).

  13. Browse Title Index

    African Journals Online (AJOL)

    Items 101 - 150 of 187 ... ... NMR and Solvent Effect Study on the Thymine-Adenine-Thymine ... animal model of schistosoma mansoni treated with myrrh or praziquantel, Abstract ... On In Vivo Paraquat Induced Oxidative Damage In Rats, Abstract.

  14. Download this PDF file

    African Journals Online (AJOL)

    Shadan

    2011-11-07

    Nov 7, 2011 ... changes such as lipid peroxidation, protein, nucleic acids and photosynthetic ..... Responses of Antioxidants to Paraquat in Pea Leaves. Plant Physiol. .... enzymes and metabolism of 14 C-substrates in isolated leaf cells of.

  15. A tristable [2]pseudo[2]rotaxane

    KAUST Repository

    Trabolsi, Ali; Fahrenbach, Albert C.; Dey, Sanjeev Kumar; Share, Andrew I.; Friedman, Douglas C.; Basu, Subhadeep; Gasa, Travis B.; Khashab, Niveen M.; Saha, Sourav; Aprahamian, Ivan; Khatib, Hussam A.; Flood, Amar H.; Stoddart, Fraser Fraser Raser

    2010-01-01

    barrier to relaxation, a supramolecular recognition site for bis-1,5-dioxynaphthalene[38]crown-10 macrocycle, and upon reduction a recognition site for the mechanically bonded cyclobis(paraquat-p-phenylene) ring. © The Royal Society of Chemistry 2010.

  16. Akinloye et al (21)

    African Journals Online (AJOL)

    reported to cause severe acute and long term health problems which eventually could lead to death. ... dependent effects of paraquat on C-reactive protein, cholesterol, triglycerides and histology of ... use in Mexico to destroy marijuana plants.

  17. MECHANISM OF OPTICAL NONLINEARITY IN “LYOTROPIC LIQUID CRYSTAL — VIOLOGEN” SYSTEM

    Directory of Open Access Journals (Sweden)

    Hanna Bordyuh

    2014-06-01

    Full Text Available In the present work we analyze the characteristics of holographic grating recording and consider a mechanism of optical nonlinearity in the lyotropic liquid crystal (LLC — viologen samples. Taking into account structural and electrooptical properties of the admixture molecules it is possible to suggest that the recording is realized due to the change of polarizability of π-electron system of coloured viologen derivatives under the action of laser radiation. The main nonlinear optical parameters such as nonlinear refraction coefficient n2, cubic nonlinear susceptibility χ(3, and hyperpolarizability γ were calculated.

  18. FORMATION AND ELECTROCHEMICAL BEHAVIOUR OF POLYION COMPLEXES FOR ELECTROCHROMIC DISPLAY MATERIAL

    Institute of Scientific and Technical Information of China (English)

    WAN Guoxiang; WANG Bing; DENG Zhenghua; LUO Chunqiao

    1988-01-01

    Formation of intermacromolecular complexes containing viologen and electron-transfer reaction occurred on the electrode modified by the complex films were studied. Compositions and morphology of the complexes depend on the properties of polyanion and chemical environment of complexation. The analytical results of cyclic voltammetry (CV) and rotating disk voltammetry(RDV) indicated: (1) active sites of viologen in network of complexes transferred single electron reversibly; (2) the redox peak currents showed excellent symmetry and stability; (3) redox potentials were related to properties of polyanions, varying from -0.4 to -0.6V (vs. SCE). Electrochromic materials with different displaying colors could be obtained by changing the structure of polyviologen.

  19. Pneumonitis and lethal pulmonary fibrosis (Hamman-Rich syndrome) due to Parathione (E605) poisoning

    International Nuclear Information System (INIS)

    Lotz, W.; Fasske, E.; Forschungsinstitut Borstel

    1986-01-01

    A patient with chronic Parathione (E 605) poisoning was observed over a period of 55 days. During that time he developed progressive changes, which were identical to those of progressive idiopathic pulmonary fibrosis. The rapid development of an alveolitis, followed by a lethal pulmonary fibrosis, differed in no way, macroscopically nor microscopically, from the lung changes in paraquat poisoning (paraquat lung). The radiologic course has been correlated with the clinical and post mortem findings. (orig.) [de

  20. Multidisciplinary research program directed toward utilization of solar energy through bioconversion of renewable resources. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Finnerty, W. R.

    1976-07-01

    Progress is reported in four research areas of solar bioconversion. The first program deals with the genetic selection of superior trees, physiological basis of vigor, tissue culture, haploid cell lines, and somatic hybridization. The second deals with the physiology of paraquat-induced oleoresin biogenesis. Separate abstracts were prepared for the other two program areas: biochemical basis of paraquat-induced oleoresin production in pines and biochemistry of methanogenesis. (JSR)

  1. Pseudorotaxane capped mesoporous silica nanoparticles for 3,4-methylenedioxymethamphetamine (MDMA) detection in water

    DEFF Research Database (Denmark)

    Lozano-Torres, Beatriz; Pascual, Lluís; Bernardos, Andrea

    2017-01-01

    Mesoporous silica nanoparticles loaded with fluorescein and capped by a pseudorotaxane, formed between a naphthalene derivative and cyclobis(paraquat-p-phenylene) (CBPQT4+), were used for the selective and sensitive fluorogenic detection of 3,4-methylenedioxymethamphetamine (MDMA).......Mesoporous silica nanoparticles loaded with fluorescein and capped by a pseudorotaxane, formed between a naphthalene derivative and cyclobis(paraquat-p-phenylene) (CBPQT4+), were used for the selective and sensitive fluorogenic detection of 3,4-methylenedioxymethamphetamine (MDMA)....

  2. Distribution of Multipple Herbicide Resistant Eleusine Indica L. Gaertn. an Oil Palm Estate in North Sumatera

    OpenAIRE

    syahputra, ahmad bayu; Purba, Edison Purba; Hasanah, Yaya Hasanah

    2016-01-01

    Goosegrass (Eleusine indica) in a block of oil palm Estate at Serdang Bedagai, North Sumatera had been controlled using glyphosate and paraquat for more than 26 years continuously. Recently, it had been reported that the two herbicides failed to control the population. The estate consists of 4000 Ha or 437 blocks which had slightly different history in weed management. The objective of this study was to determine the distribution Eleusine indica Resistant to glyphosate and paraquat in the oil...

  3. Photosynthesis involvement in the mechanism of action of diphenyl ether herbicides.

    Science.gov (United States)

    Ensminger, M P; Hess, F D

    1985-05-01

    Photosynthesis is not required for the toxicity of diphenyl ether herbicides, nor are chloroplast thylakoids the primary site of diphenyl ether herbicide activity. Isolated spinach (Spinacia oleracea L.) chloroplast fragments produced malonyl dialdehyde, indicating lipid peroxidation, when paraquat (1,1'-dimethyl-4,4'-bipyridinium ion) or diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were added to the medium, but no malonyl dialdehyde was produced when chloroplast fragments were treated with the methyl ester of acifluorfen (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid), oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene], or MC15608 (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-chlorobenzoate). In most cases the toxicity of acifluorfen-methyl, oxyfluorfen, or MC15608 to the unicellular green alga Chlamydomonas eugametos (Moewus) did not decrease after simultaneous treatment with diuron. However, diuron significantly reduced cell death after paraquat treatment at all but the highest paraquat concentration tested (0.1 millimolar). These data indicate electron transport of photosynthesis is not serving the same function for diphenyl ether herbicides as for paraquat. Additional evidence for differential action of paraquat was obtained from the superoxide scavenger copper penicillamine (copper complex of 2-amino-3-mercapto-3-methylbutanoic acid). Copper penicillamine eliminated paraquat toxicity in cucumber (Cucumis sativus L.) cotyledons but did not reduce diphenyl ether herbicide toxicity.

  4. Photosynthesis Involvement in the Mechanism of Action of Diphenyl Ether Herbicides 1

    Science.gov (United States)

    Ensminger, Michael P.; Hess, F. Dan

    1985-01-01

    Photosynthesis is not required for the toxicity of diphenyl ether herbicides, nor are chloroplast thylakoids the primary site of diphenyl ether herbicide activity. Isolated spinach (Spinacia oleracea L.) chloroplast fragments produced malonyl dialdehyde, indicating lipid peroxidation, when paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) or diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] were added to the medium, but no malonyl dialdehyde was produced when chloroplast fragments were treated with the methyl ester of acifluorfen (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid), oxyfluorfen [2-chloro-1-(3-ethoxy-4-nitrophenoxy)-4-(trifluoromethyl)benzene], or MC15608 (methyl 5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-chlorobenzoate). In most cases the toxicity of acifluorfen-methyl, oxyfluorfen, or MC15608 to the unicellular green alga Chlamydomonas eugametos (Moewus) did not decrease after simultaneous treatment with diuron. However, diuron significantly reduced cell death after paraquat treatment at all but the highest paraquat concentration tested (0.1 millimolar). These data indicate electron transport of photosynthesis is not serving the same function for diphenyl ether herbicides as for paraquat. Additional evidence for differential action of paraquat was obtained from the superoxide scavenger copper penicillamine (copper complex of 2-amino-3-mercapto-3-methylbutanoic acid). Copper penicillamine eliminated paraquat toxicity in cucumber (Cucumis sativus L.) cotyledons but did not reduce diphenyl ether herbicide toxicity. PMID:16664206

  5. 不同富营养化程度下Cd和百草枯对浮萍部分生理指标的影响%Effect of paraquat and cadmium on some physiological indices of duckweed under different degree eutrophication

    Institute of Scientific and Technical Information of China (English)

    王雪琪; 李凡修; 黄河

    2009-01-01

    研究了不同富营养化程度下百草枯和Cd对浮萍(Lemna minor Linn)可溶性糖含量、植物组织中游离氨基酸含量、丙二醛(MDA)含量的影响.结果表明:随富营养化程度的升高,在百草枯和Cd单一及复合污染条件作用下,可溶性糖含量显著下降,而氨基酸和MDA含量随污染物浓度的增加而显著提高.百草枯和Cd单一及复合污染对浮萍的毒害作用也很大,尤其是两者复合污染作用时,效果更显著.

  6. Efeitos de dessecantes no controle de plantas daninhas na cultura da soja Effects of burndown herbicides in weed control in soybean crop

    Directory of Open Access Journals (Sweden)

    S.O. Procópio

    2006-01-01

    Full Text Available Este trabalho teve como objetivo avaliar a eficiência do glyphosate e da mistura comercial paraquat + diuron, bem como o efeito do intervalo entre as aplicações desses herbicidas e a semeadura da soja, sobre o controle e a rebrota de Digitaria insularis, Synedrellopsis grisebachii e Leptochloa filiformis. O experimento foi conduzido em área de soja em sistema de plantio direto, utilizando-se o delineamento de blocos casualizados com nove tratamentos e quatro repetições. Foram avaliados os seguintes tratamentos: glyphosate no dia da semeadura e um, dois e cinco dias antes desta; paraquat + diuron 20 dias antes e no dia da semeadura; glyphosate 10 dias antes da semeadura e paraquat + diuron no dia da semeadura; glyphosate 15 dias antes da semeadura e paraquat + diuron no dia da semeadura; glyphosate 20 dias antes da semeadura e paraquat + diuron no dia da semeadura; e testemunha infestada. Verificou-se controle satisfatório e impedimento de rebrota de D. insularis e L. filiformis quando o glyphosate foi aplicado cinco dias antes da semeadura da soja ou quando foi realizada aplicação seqüencial de glyphosate e paraquat + diuron. Aplicações seqüenciais da mistura comercial de paraquat + diuron não foram eficientes no controle e no impedimento da rebrota de D. insularis e L. filiformis. S. grisebachii mostrou-se tolerante ao glyphosate.The objectives of this work were to evaluate the efficiency of glyphosate and preformulated mixture paraquat + diuron as well as the effect of the interval between herbicide applications and soybean sowing on the control and re-growth impairment of the following weeds: Digitaria insularis, Synedrellopsis grisebach and Leptochloa filiformis. The experiment was carried out in a soybean area under no-till system and was arranged in a randomized block design, with 9 treatments and four replications. The following treatments were evaluated: glyphosate applied on sowing day; one day before sowing day; two days

  7. Multidisciplinary research program directed toward utilization of solar energy through bioconversion of renewable resources

    Energy Technology Data Exchange (ETDEWEB)

    1980-07-01

    Progress is reported in this multidisciplinary research program. Genetic selection of superior trees, physiological basis of vigor, tissue culture systems leading to cloning of diploid and haploid cell lines are discussed in the Program A report. The physiological basis of enhanced oleoresin formation in southern pines when treated with sublethal concentrations of the herbicide paraquat was investigated in Program B. In Program C, metabolic changes in the stems of slash pine, in vivo, after application with paraquat were determined. The use of phdoem and xylem tissue slices as a laboratory model for studying paraquat associated- and normal-terpene synthesis in pines is discussed. The biochemistry and physiology of methane formation from cellulose during anaerobic fermentation are discussed in the Program D report. (DMC)

  8. Long-lived ames dwarf mice are resistant to chemical stressors.

    Science.gov (United States)

    Bokov, Alex F; Lindsey, Merry L; Khodr, Christina; Sabia, Marian R; Richardson, Arlan

    2009-08-01

    To probe the connection between longevity and stress resistance, we compared the sensitivity of Ames long-lived dwarf mice and control littermates with paraquat, diquat, and dobutamine. In young adult animals, 95% of male and 39% of female controls died after paraquat administration, but no dwarf animals died. When the experiment was repeated at an older age or a higher dosage of paraquat, dwarf mice still showed greater resistance. Dwarf mice also were more resistant to diquat; 80% of male and 60% of female controls died compared with 40% and 20% of dwarf mice, despite greater sensitivity of dwarf liver to diquat. Dwarf mice were also less sensitive to dobutamine-induced cardiac stress and had lower levels of liver and lung F(2)-isoprostanes. This is the first direct in vivo evidence that long-lived Ames dwarf mice have enhanced resistance to chemical insult, particularly oxidative stressors.

  9. The Response of Lemna minor to Mixtures of Pesticides That Are Commonly Used in Thailand.

    Science.gov (United States)

    Tagun, Rungnapa; Boxall, Alistair B A

    2018-04-01

    In the field, aquatic organisms are exposed to multiple contaminants rather than to single compounds. It is therefore important to understand the toxic interactions of co-occurring substances in the environment. The aim of the study was to assess the effects of individual herbicides (atrazine, 2,4-D, alachlor and paraquat) that are commonly used in Thailand and their mixtures on Lemna minor. Plants were exposed to individual and binary mixtures for 7 days and the effects on plant growth rate were assesed based on frond area measurements. Experimental observations of mixture toxicity were compared with predictions based on single herbicide exposure data using concentration addition and independent action models. The single compound studies showed that paraquat and alachlor were most toxic to L. minor, followed by atrazine and then 2,4-D. For the mixtures, atrazine with 2,4-D appeared to act antagonistically, whereas alachlor and paraquat showed synergism.

  10. Misturas de herbicidas para o controle de plantas daninhas do gênero Commelina Herbicide mixtures to control weeds of the genus Commelina

    Directory of Open Access Journals (Sweden)

    C.P. Ronchi

    2002-08-01

    Full Text Available Este trabalho teve como objetivo avaliar a eficiência de misturas de herbicidas no controle de duas espécies de trapoeraba, Commelina diffusa e Commelina benghalensis. Para isso, segmentos de caule dessas espécies foram transplantados em vasos contendo 12 L de substrato. Após 120 dias, foram aplicados os seguintes tratamentos: carfentrazone-ethyl (30 g ha¹ em mistura com glyphosate (720 g ha-1 e/ou glyphosate potássico (720 g ha-1; glyphosate (720 g ha-1 em mistura com flumioxazin (60 g ha-1 e/ou 2,4-D (670 g ha-1 e/ou metsulfuron methyl (4 g ha-1; oxyfluorfen em mistura com sulfentrazone (480 + 375 g ha¹; aplicações seqüenciais, com intervalo de 21 dias, de [(paraquat + diuron / (carfentrazone-ethyl + glyphosate] [(200+400/(30+720] e de [(paraquat + diuron / (paraquat + diuron] [(200+400/(200+400]; e testemunha sem aplicação de herbicida. Cada espécie constituiu um experimento, sendo ambos conduzidos no delineamento em blocos casualizados, com quatro repetições. Foram feitas avaliações de controle das trapoerabas e da biomassa fresca da parte aérea. Os tratamentos mais eficientes no controle das trapoerabas foram as aplicações seqüenciais, com intervalo de 21 dias, de (paraquat + diuron / (carfentrazone-ethyl + glyphosate e de (paraquat + diuron / (paraquat + diuron, seguidas das misturas em tanque de 2,4-D + glyphosate e de carfentrazone-ethyl + glyphosate e/ou glyphosate potássico.This research was conducted to evaluate the efficiency of herbicide mixtures in the control of two dayflower species, Commelina diffusa and Commelina benghalensis. These species were grown from stem segments in 12 L pots during 120 days. Subsequently, a randomized complete block design with four replicates was performed for each species. The treatments were carfentrazone-ethyl combined to either glyphosate or glyphosate-potassium salt (30 + 720 g ha-1; glyphosate (720 g ha-1 combined to flumioxazin (60 g ha-1, or 2.4-D (670 g ha-1 or

  11. Curcumin Rescues a PINK1 Knock Down SH-SY5Y Cellular Model of Parkinson's Disease from Mitochondrial Dysfunction and Cell Death.

    Science.gov (United States)

    van der Merwe, Celia; van Dyk, Hayley Christy; Engelbrecht, Lize; van der Westhuizen, Francois Hendrikus; Kinnear, Craig; Loos, Ben; Bardien, Soraya

    2017-05-01

    Parkinson's disease (PD) is a neurodegenerative disorder characterised by the loss of dopaminergic neurons in the substantia nigra. Mutations in the PINK1 gene result in an autosomal recessive form of early-onset PD. PINK1 plays a vital role in mitochondrial quality control via the removal of dysfunctional mitochondria. The aim of the present study was to create a cellular model of PD using siRNA-mediated knock down of PINK1 in SH-SY5Y neuroblastoma cells The possible protective effects of curcumin, known for its many beneficial properties including antioxidant and anti-inflammatory effects, was tested on this model in the presence and absence of paraquat, an additional stressor. PINK1 siRNA and control cells were separated into four treatment groups: (i) untreated, (ii) treated with paraquat, (iii) pre-treated with curcumin then treated with paraquat, or (iv) treated with curcumin. Various parameters of cellular and mitochondrial function were then measured. The PINK1 siRNA cells exhibited significantly decreased cell viability, mitochondrial membrane potential (MMP), mitochondrial respiration and ATP production, and increased apoptosis. Paraquat-treated cells exhibited decreased cell viability, increased apoptosis, a more fragmented mitochondrial network and decreased MMP. Curcumin pre-treatment followed by paraquat exposure rescued cell viability and increased MMP and mitochondrial respiration in control cells, and significantly decreased apoptosis and increased MMP and maximal respiration in PINK1 siRNA cells. These results highlight a protective effect of curcumin against mitochondrial dysfunction and apoptosis in PINK1-deficient and paraquat-exposed cells. More studies are warranted to further elucidate the potential neuroprotective properties of curcumin.

  12. Untitled

    Indian Academy of Sciences (India)

    Iot A a. (1) pH - 108. ------ -----. -200 -800 -400 O - 1200 -800 - 400 0. mV NHE mv NHE. Figure 3. CV of 1 and 2 at pH = 108. The voltammograms of compound 1 and 2 are more complex than, for example, those of methyl viologen. Shoulders, appearing in the CV's of 1 and 2, indicate competing reactions. Rapid reversible or ...

  13. Clostridium beijerinckii mutant obtained atmospheric pressure glow discharge generates enhanced electricity in a microbial fuel cell.

    Science.gov (United States)

    Liu, Jun; Guo, Ting; Wang, Dong; Ying, Hanjie

    2015-01-01

    A Clostridium beijerinckii mutant M13 was derived from C. beijerinckii NCIMB 8052 by atmospheric pressure glow discharge. C. beijerinckii M13 generated a maximum output power density of 79.2 mW m(-2) and a maximum output voltage of 230 mV in a microbial fuel cell containing 1 g glucose l(-1) as carbon source and 0.15 g methyl viologen l(-1) as an electron carrier.

  14. An Electrochemical Investigation into the Corrosion Protection Properties of Coatings for the Active Metal Copper

    OpenAIRE

    Carragher, Ursula

    2013-01-01

    In the research presented in this thesis, corrosion protection films were synthesised and characterised. The films were based on polypyrrole (PPy) coatings doped with combinations of tartrate, oxalate and dodecylbenzene sulfonate (DBS) along with the incorporation of multiwalled carbon nanotubes (MWCNT), and viologen films adsorbed at copper. The corrosion protective properties of these films were studied and compared to the uncoated copper substrate. They were assessed and stu...

  15. Determination of one-electron reduction potentials of some radiosensitive compounds by pulse radiolysis

    International Nuclear Information System (INIS)

    Zuo Zhihua; Yao Side; Li Hucheng; Lin Nianyun; Jin Yizun

    1994-01-01

    One-electron reduction potential (E 7 1 ) is one of the important parameters of radiosensitive compound with high electron affinity. In this work one-electron reduction potentials of some radiosensitizers, such as Miso, 911, CMNa, SMU-1, SMU-2, SMD, SNN, S 3 and BSO, were determined pulse radiolytically by using anthraquinone-2-sulfate (AQS), duroquinone (DQ) and methyl viologen (MV 2+ ) as references

  16. Author Details

    African Journals Online (AJOL)

    Dose-Time Effect of Crude Oil and Hydro-test Effluent on Freshwater and Brackish Water Habitats Abstract PDF · Vol 4, No 3 (2010) - Articles Effects of lindane pretreatment on paraquat toxicity in female wistar rats (Rattus rattus) Abstract · Vol 7, No 5 (2010) - Articles Effects of lemon juice on the reproductive hormones of ...

  17. In vitro screening of selected herbicides on rhizosphere mycoflora ...

    African Journals Online (AJOL)

    In vitro screening of five selected herbicides at different concentrations on rhizosphere mycoflora from yellow pepper (capsicum annum L var. Nsukka yellow) seedlings at Nsukka were investigated. The herbicides employed for this study were Paraquat, Glyphosate, Primextra, Atrazine and Linuron. The isolated rhizosphere ...

  18. Phytotoxic, insecticidal and leishmanicidal activities of aerial parts of ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-02-22

    Feb 22, 2010 ... polypharmacy, it has been practiced to promote urine ... ment of PCSIR Laboratories Peshawar and a specimen with catalo- gue No: ... GI = % Growth Inhibition, Standard drug = Paraquat (3.142µg/ml). .... the problem of weed resistance. ... regulator, dimilin, against stored grain pest Callosobruchus analis.

  19. Responses of the African catfish Clarias gariepinus to long-term ...

    African Journals Online (AJOL)

    ... environment by pesticides results in a decrease in fish productivity and may elevate concentrations of undesirable chemicals in edible fish tissues. The effects of long-term exposure of Clarias gariepinus juveniles to sublethal concentrations of glyphosate and paraquat, two commonly used herbicides, for eight weeks were ...

  20. Oxidative stress provokes distinct transcriptional responses in the stress-tolerant atr7 and stress-sensitive loh2 Arabidopsis thaliana mutants as revealed by multi-parallel quantitative real-time PCR analysis of ROS marker and antioxidant genes

    NARCIS (Netherlands)

    Mehterov, Nikolay; Balazadeh, Salma; Hille, Jacques; Toneva, Valentina; Mueller-Roeber, Bernd; Gechev, Tsanko

    2012-01-01

    The Arabidopsis thaliana atr7 mutant is tolerant to oxidative stress induced by paraquat (PQ) or the catalase inhibitor aminotriazole (AT), while its original background loh2 and wild-type plants are sensitive. Both, AT and PQ which stimulate the intracellular formation of H2O2 or superoxide anions,

  1. Egyptian Journal of Biochemistry and Molecular Biology - Vol 24, No ...

    African Journals Online (AJOL)

    Protective role of green tea polyphenols against paraquat induced oxidative stress in rat liver · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD FULL ... Role of reduced glutathione, nitric oxide and some trace elements in Alzheimer's disease and vascular dementia · EMAIL FULL TEXT EMAIL FULL TEXT DOWNLOAD ...

  2. 77 FR 16679 - Emergency Planning and Notification; Emergency Planning and List of Extremely Hazardous...

    Science.gov (United States)

    2012-03-22

    ... solids like paraquat dichloride limit their capacity to become airborne. On January 23, 2003, EPA filed a..., emulsions, or pastes. \\2\\ The amount present on-site for EHSs that are in a molten form is calculated by..., suspensions, emulsions, and pastes. Additionally, EPA has also revised the regulations for 40 CFR 355.16(c) to...

  3. Cytotoxicity of MEIC chemicals Nos. 11-30 in 3T3 mouse fibroblasts with and without microsomal activation

    DEFF Research Database (Denmark)

    Rasmussen, Eva

    1999-01-01

    acid, propranolol, thioridazine, lithium sulfate, copper sulfate and thallium sulfate, whereas the cytotoxicity of 1,1,1-trichloroethylene, phenol, nicotine, and paraquat was significantly increased by use of the microsomal activation mixture. These cytotoxicity data are in line with observations...

  4. Effects of Commonly Used Pesticides in China on the Mitochondria and Ubiquitin-Proteasome System in Parkinson’s Disease

    OpenAIRE

    Chen, Tingting; Tan, Jieqiong; Wan, Zhengqing; Zou, Yongyi; Kessete Afewerky, Henok; Zhang, Zhuohua; Zhang, Tongmei

    2017-01-01

    Evidence continues to accumulate that pesticides are the leading candidates of environmental toxins that may contribute to the pathogenesis of Parkinson’s disease. The mechanisms, however, remain largely unclear. According to epidemiological studies, we selected nine representative pesticides (paraquat, rotenone, chlorpyrifos, pendimethalin, endosulfan, fenpyroximate, tebufenpyrad, trichlorphon and carbaryl) which are commonly used in China and detected the effects of the pesticides on mitoch...

  5. Experiment list: SRX1084161 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available tissue=whole animal || gender=female || age=1-3 days || genotype=k6801/k6801;gHA-KDM5 || chip antibody=HA ht...,0 GSM1811343: P1 HA ChIPSeq; Drosophila melanogaster; ChIP-Seq source_name=Female whole animal_paraquat ||

  6. Experiment list: SRX1084162 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available 0 GSM1811344: P2 HA ChIPSeq; Drosophila melanogaster; ChIP-Seq source_name=Female whole animal_paraquat || tissue=whole animal || gen...der=female || age=1-3 days || genotype=k6801/k6801;gHA-KDM5 || chip antibody=HA htt

  7. Effect of four herbicides on microbial population, soil organic matter ...

    African Journals Online (AJOL)

    The effect of four herbicides (atrazine, primeextra, paraquat and glyphosate) on soil microbial population, soil organic matter and dehydrogenase activity was assessed over a period of six weeks. Soil samples from cassava farms were treated with herbicides at company recommended rates. Soil dehydrogenase activity was ...

  8. Bis(pyrrolo)tetrathiafulvalene - An Efficient Pi-Donor in Supramolecular Chemistry

    DEFF Research Database (Denmark)

    Lau, Jesper; Nielsen, Mogens Brøndsted; Thorup, Niels

    1999-01-01

    The synthesis of three novel macrocycles 3-5 based on the two electron donors bis(2,5-dimethyl- pyrrolo)[3,4-d]tetrathiafulvalene (1) and 1,4-hydroquinone is presented. Their abilities to include the electron acceptor paraquat (6) have been investigated by UV/Vis and sup 1 H NMR spectroscopy and ...

  9. Potent Protective Effect Of α -Tocopherol And Fish Oil On In Vivo ...

    African Journals Online (AJOL)

    The potential protective role of α-tocopherol and fish oil against oxidative damage induced by paraquat were investigated. Forty male albino rats with average body weight of 100-120 gm were housed in 8 groups of 5 rats each. The first group served as control and injected with saline, group 2 was injected with a single dose ...

  10. Possibilidade de aplicação de misturas de herbicidas de ação total com Jato dirigido em mamoneira de porte anão Possibility of applaying total action herbicide tank mixture using direct sprayer on dwarf internode castor bean

    Directory of Open Access Journals (Sweden)

    C.D.G. Maciel

    2008-06-01

    Full Text Available Com o objetivo de avaliar os efeitos da aplicação em jato dirigido com e sem proteção do bico de pulverização através de chapéu-de-napoleão para misturas de herbicidas de ação total na cultura da mamoneira de porte anão, na safra 2004/2005, um experimento foi conduzido no município de Garça-SP, utilizando-se o híbrido Lyra e espaçamento de 1,0 x 0,5 m. O delineamento experimental utilizado foi o de blocos casualizados, com tratamentos em esquema fatorial 2 x 10, com quatro repetições, em que o primeiro fator representou a forma de aplicação de jato dirigido com e sem uso de chapéu-de-napoleão e o segundo os herbicidas: glyphosate (0,72 kg ha-1; glyphosate + 2,4-D (0,72 + 0,35 kg ha-1; glyphosate + flumioxazin (0,72 + 0,025 kg ha-1; glyphosate + carfentrazone-ethyl (0,72 + 0,016 kg ha-1; glyphosate + diuron (0,72 + 0,75 kg ha-1; MSMA + diuron (1,44+ 0,75 kg ha-1; paraquat + diuron (0,9 kg ha-1; paraquat + diquat (0,20 + 0,20 kg ha-1; paraquat + bentazon (0,40 + 0,48 kg ha-1; e testemunha capinada. A aplicação dos herbicidas foi feita em pós-emergência das plantas daninhas, nas entrelinhas da cultura, utilizando-se pulverizador costal pressurizado com CO2, com uma ponta XR 8002-VS para o uso de chapéu-de-napoleão e duas pontas XR 11002-VS, espaçadas de 50 cm, para condição sem proteção, ambas com consumo de calda equivalente a 200 L ha-1. O herbicida glyphosate e as misturas de paraquat + bentazon, glyphosate + 2,4-D e paraquat + diquat proporcionaram os maiores níveis de produtividade da mamoneira Lyra quando aplicados em jato dirigido e com auxílio de chapéu-de-napoleão. As misturas paraquat + bentazon (0,40 + 0,48 kg ha-1 e paraquat + diquat (0,20 + 0,20 kg ha-1 demonstraram ser as mais indicadas para aplicação em jato dirigido com proteção do bico de pulverização.An experiment was carried out in Garca-SP to evaluate the effects of application using a direct sprayer with and without "Napoleons's hat

  11. Reproductive organ and vascular specific promoter of the rice plasma membrane Ca2+ATPase mediates environmental stress responses in plants.

    Science.gov (United States)

    Huda, Kazi Md Kamrul; Banu, Mst Sufara Akhter; Pathi, Krishna Mohan; Tuteja, Narendra

    2013-01-01

    Plasma membrane Ca(2+)ATPase is a transport protein in the plasma membrane of cells and helps in removal of calcium (Ca(2+)) from the cell, hence regulating Ca(2+) level within cells. Though plant Ca(2+)ATPases have been shown to be involved in plant stress responses but their promoter regions have not been well studied. The 1478 bp promoter sequence of rice plasma membrane Ca(2+)ATPase contains cis-acting elements responsive to stresses and plant hormones. To identify the functional region, serial deletions of the promoter were fused with the GUS sequence and four constructs were obtained. These were differentially activated under NaCl, PEG cold, methyl viologen, abscisic acid and methyl jasmonate treatments. We demonstrated that the rice plasma membrane Ca(2+)ATPase promoter is responsible for vascular-specific and multiple stress-inducible gene expression. Only full-length promoter showed specific GUS expression under stress conditions in floral parts. High GUS activity was observed in roots with all the promoter constructs. The -1478 to -886 bp flanking region responded well upon treatment with salt and drought. Only the full-length promoter presented cold-induced GUS expression in leaves, while in shoots slight expression was observed for -1210 and -886 bp flanking region. The -1210 bp deletion significantly responded to exogenous methyl viologen and abscisic acid induction. The -1210 and -886 bp flanking region resulted in increased GUS activity in leaves under methyl jasmonate treatments, whereas in shoots the -886 bp and -519 bp deletion gave higher expression. Salicylic acid failed to induce GUS activities in leaves for all the constructs. The rice plasma membrane Ca(2+)ATPase promoter is a reproductive organ-specific as well as vascular-specific. This promoter contains drought, salt, cold, methyl viologen, abscisic acid and methyl jasmonate related cis-elements, which regulated gene expression. Overall, the tissue-specificity and inducible nature of this

  12. Aplicação de dessecantes na cultura de soja: teor de umidade nas sementes e biomassa nas plantas Application dissecants in soybean: degree of humidity in the plant's seeds and biomass

    Directory of Open Access Journals (Sweden)

    A.L.S. Lacerda

    2003-12-01

    Full Text Available Os objetivos deste trabalho foram avaliar a eficácia dos dessecantes e determinar a melhor época de aplicação na cultura de soja. O delineamento experimental utilizado foi em blocos casualizados, estando os tratamentos dispostos em esquema fatorial 3x3 e 4x4 de produtos (dessecantes e épocas de aplicação, nos anos agrícolas 1996/97 e 1997/98, respectivamente. Os dessecantes utilizados foram: paraquat, diquat e paraquat + diquat em 1996/97 e paraquat, diquat, paraquat + diquat e glufosinato de amônio em 1997/98, respectivamente nas dosagens de 0,4, 0,3 e 0,2 + 0,15; e 0,4, 0,3, 0,2 + 0,15 e 0,4 kg i.a. ha¹. Como épocas, foram realizadas três aplicações em 1996/97 e quatro em 1997/98, com intervalos de cinco dias a partir do estádio R6. Após análise e interpretação dos resultados, concluiu-se que os dessecantes foram eficazes na dessecação e que o teor de umidade das sementes entre 50 e 60%, as plantas com baixa incidência de vagens amarelas e marrons e a relação peso de biomassa verde de vagens/biomassa verde total de cerca de 0,5 foram características marcantes na determinação da melhor época de aplicação dos dessecantes.The objectives of this work were to evaluate dissecant efficiency and determine the best application time for soybean crop. The experimental design was randomized blocks in factorial schemes 3x3 and 4x4 (dissecants x application time, in 1996/1997 and 1997/1998, respectively. The dissecants applied were: paraquat, diquat and paraquat + diquat in 1996/97 and paraquat, diquat, paraquat + diquat and ammonium glufosinate in 1997/1998, respectively, in the following doses: 0.4; 0.3 and 0.2 + 0.15 and 0.4; 0.3; 0.2 + 0.15 and 0.4 kg a.i. ha-1 Three application times were used in 1996/1997 and four in 1997/1998, with intervals of five days starting from stage R6. Analysis and interpretation of the results allowed to conclude that the dissecants were efficient and that seed moisture between 50 and 60

  13. Molecular identification of catalases from Nicotiana plumbaginifolia (L.).

    Science.gov (United States)

    Willekens, H; Villarroel, R; Van Montagu, M; Inzé, D; Van Camp, W

    1994-09-19

    We have isolated three different catalase cDNAs from Nicotiana plumbaginifolia (cat1, cat2, and cat3) and a partial sequence of a fourth catalase gene (cat4) that shows no discernible expression based on Northern analysis. The catalase sequences were used to determine the similarity with other plant catalases and to study the transcriptional response to paraquat, 3-aminotriazole, and salicylic acid. 3-Aminotriazole induces mRNA levels of cat1, cat2 and cat3, indicating that a reduction in catalase activity positively affects catalase mRNA abundance. Salicylic acid that binds catalase in vitro, had no effect on catalase transcript levels at physiological concentrations. Paraquat resulted in the induction of cat1.

  14. Toxicidade de herbicidas utilizados na cultura da cana-de-açúcar à bactéria diazotrófica Azospirillum brasilense Toxicity of herbicides applied on sugarcane to the diazotrophic bacterium Azospirillum brasilense

    Directory of Open Access Journals (Sweden)

    S.O Procópio

    2011-01-01

    Full Text Available Objetivou-se neste trabalho identificar herbicidas utilizados na cultura da cana-de-açúcar que não alteram o crescimento ou a capacidade de fixação biológica de nitrogênio (FBN da bactéria diazotrófica Azospirillum brasi lense. Dezoito herbicidas - paraquat, ametryn, amicarbazone, diuron, metribuzin, [hexazinone + diuron], [hexazinone + clomazone], clomazone, isoxaflutole, sulfentrazone, oxyfluorfen, imazapic, imazapyr, [trifloxysulfuron-sodium + ametryn], S-metolachlor, glyphosate, MSMA e 2,4-D - foram testados em suas doses comerciais quanto ao impacto sobre o crescimento da bactéria em meio líquido DIGs. As variáveis capacidade de suporte de crescimento (carrying capacity do meio de cultura, duração da fase lag e tempo de geração de A. brasilense foram calculadas a partir de dados de densidade ótica obtidos, em intervalos regulares, durante a incubação de culturas por 55 h. O impacto dos herbicidas na atividade da nitrogenase de A. brasilense foi avaliado em meio semissólido NFb, sem N, pela técnica da atividade de redução do acetileno (ARA. Os efeitos dos herbicidas sobre as variáveis de crescimento e ARA foram comparados ao controle pelo teste de Dunnett. Paraquat, oxyfluorfen, [trifloxysulfuron-sodium + ametryn] e glyphosate reduziram a capacidade do meio DIGs em suportar o crescimento de A. brasilense. Esse efeito foi associado ao aumento da duração da fase lag e do tempo de geração para [trifloxysulfuron-sodium + ametryn] e ao aumento no tempo de geração para glyphosate. MSMA, paraquat e amicarbazone reduzem a FBN in vitro de A. brasilense, porém essa redução é mais severa na presença do paraquat. Os demais herbicidas não alteram o crescimento e a FBN de A. brasilense.The objective of this work was to identify the herbicides applied on sugarcane that do not affect the growth nor the process of biological nitrogen fixation (BNF of the diazotrophic bacterium Azospirillum brasilense. Commercial doses of

  15. Chemistry and Physics of Solid Surfaces 5

    Science.gov (United States)

    1984-04-01

    Superconductivity: M.B.Maple, UCSD, La Jolla Metals and Alloys, Solid-State Electron Microscopy. S.Amelinckx, Mol Positron Annihilation : P.Hautojlirvi...position of the conduction band edge of the colloidal TiO2 particle influences greatly the rate of MV+ formation. Figure 5.3 shows data obtained 116 B0...Reduction of Viologens on Colloidal TiO2 Irradiation of TiO 2 sols in alkaline solutions in the presence of C14MV 2+ leads to the formation of doubly

  16. Application of Nanostructures in Electrochromic Materials and Devices: Recent Progress

    Directory of Open Access Journals (Sweden)

    Jin Min Wang

    2010-11-01

    Full Text Available The recent progress in application of nanostructures in electrochromic materials and devices is reviewed. ZnO nanowire array modified by viologen and WO3, crystalline WO3 nanoparticles and nanorods, mesoporous WO3 and TiO2, poly(3,4-ethylenedioxythiophene nanotubes, Prussian blue nanoinks and nanostructures in switchable mirrors are reviewed. The electrochromic properties were significantly enhanced by applying nanostructures, resulting in faster switching responses, higher stability and higher optical contrast. A perspective on the development trends in electrochromic materials and devices is also proposed.

  17. TECHNICAL REPORT

    Energy Technology Data Exchange (ETDEWEB)

    ADAMS, RICHARD D., PhD.

    2011-04-06

    Cadmium selenide nanoparticles and nanoclusters were prepared and added to polymer solar cells to improve their photon capture ability. These nanoparticles did exhibit some beneficial effects on the photon conversion efficiencies of selected polymer solar cells. Ternary bulk heterojunction systems based on composites of methyl viologen-doped, CdSe nanoparticles blended with poly (3-hexothiopene) (P3HT) and 6, 6-phenyl C{sub 61}-butyric acid methyl ester (PCBM) were also tested. It was found that the devices with methyl viologen-doped CdSe nanoparticles do produce more photocurrent in a region surrounding the absorption peak of the particles (560 to 660nm) when compared to pristine P3HT:PCBM devices. Gold nanorods were also prepared and tested in some solar cells. These nanorods did produce a very small enhancement in photon absorbance, but the observed increase the photon conversion efficiency was not sufficient to make the effort worthwhile. Our goals were (1) to prepare cadmium sulfide and cadmium selenide clusters and nanoparticles to be tested as photon absorbers to enhance the photon conversion efficiency of polymer solar polymer solar cells and (2) to prepare gold and silver nanorods to be added to polymer solar cells to enhance their photon capture capability. The cadmium sulfide and cadmium selenide nanoparticles and some new nanoclusters were prepared. The cadmium selenide nanoparticles were also tested in solar cells and did exhibit some positive effects when they were combined with certain co-absorbing polymers. Due to solubility problems that were not solved in the available time, the new nanoclusters were not tested in solar cells. Ternary bulk heterojunction systems based on composites of methyl viologen doped, CdSe nanoparticles blended with poly (3-hexothiopene) (P3HT) and 6, 6-phenyl C61-butyric acid methyl ester (PCBM) have been examined in detail. The methyl viologen was added to promote charge separation of the initially formed excitons. It was

  18. Myrsinoic A acid and its derivative: in vitro inhibitors of photosynthesis; Acido myrsinoico A e derivado: inibidores da fotossintese in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Burger, Marcela Carmen de M.; Oliveira, Gracielle S. de; Menezes, Antonio Carlos S [Universidade Estadual de Goias, Anapolis, GO (Brazil). Unidade Universitaria de Ciencias Exatas e Tecnologicas; Vieira, Paulo Cezar; Silva, Maria Fatima das G.F. da [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil). Dept. de Quimica; Veiga, Thiago A.M., E-mail: tveiga@unifesp.br [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil). Inst. de Ciencias Ambientais, Quimicas e Farmaceuticas. Dept. de Ciencias Exatas e da Terra

    2012-07-01

    Myrsinoic A acid, isolated from Myrsine cuneifolia and its hydrogenated derivative had their effect on photosynthesis tested. The compounds inhibited the electron flow (basal, phosphorylating and uncoupled) from water to methyl viologen; therefore, they act as Hill reaction inhibitors in spinach thylakoids. They inhibited partial reactions of PSII electron flow from water to 2,5-dichloro-1,4-benzoquinone, from water to sodium silicomolybdate, and partially electron flow from diphenylcarbazide to 2,6-dichloroindophenol. Their inhibition sites were at the donor and acceptor sides of PSII, between P{sub 680} and Q{sub A}. Chlorophyll {alpha} fluorescence measurements confirmed the behavior of the compounds (pool of quinones). (author)

  19. Myrsinoic A acid and its derivative: in vitro inhibitors of photosynthesis

    International Nuclear Information System (INIS)

    Burger, Marcela Carmen de M.; Oliveira, Gracielle S. de; Menezes, Antonio Carlos S.; Vieira, Paulo Cezar; Silva, Maria Fatima das G.F. da; Veiga, Thiago A.M.

    2012-01-01

    Myrsinoic A acid, isolated from Myrsine cuneifolia and its hydrogenated derivative had their effect on photosynthesis tested. The compounds inhibited the electron flow (basal, phosphorylating and uncoupled) from water to methyl viologen; therefore, they act as Hill reaction inhibitors in spinach thylakoids. They inhibited partial reactions of PSII electron flow from water to 2,5-dichloro-1,4-benzoquinone, from water to sodium silicomolybdate, and partially electron flow from diphenylcarbazide to 2,6-dichloroindophenol. Their inhibition sites were at the donor and acceptor sides of PSII, between P 680 and Q A . Chlorophyll α fluorescence measurements confirmed the behavior of the compounds (pool of quinones). (author)

  20. Electrochemical Single-Molecule Transistors with Optimized Gate Coupling

    DEFF Research Database (Denmark)

    Osorio, Henrry M.; Catarelli, Samantha; Cea, Pilar

    2015-01-01

    Electrochemical gating at the single molecule level of viologen molecular bridges in ionic liquids is examined. Contrary to previous data recorded in aqueous electrolytes, a clear and sharp peak in the single molecule conductance versus electrochemical potential data is obtained in ionic liquids....... These data are rationalized in terms of a two-step electrochemical model for charge transport across the redox bridge. In this model the gate coupling in the ionic liquid is found to be fully effective with a modeled gate coupling parameter, ξ, of unity. This compares to a much lower gate coupling parameter...

  1. Ultrafast static and diffusion-controlled electron transfer at Ag 29 nanocluster/molecular acceptor interfaces

    KAUST Repository

    Aly, Shawkat Mohammede; AbdulHalim, Lina G.; Besong, Tabot M.D.; Soldan, Giada; Bakr, Osman; Mohammed, Omar F.

    2015-01-01

    Efficient absorption of visible light and a long-lived excited state lifetime of silver nanoclusters (Ag29 NCs) are integral properties for these new clusters to serve as light-harvesting materials. Upon optical excitation, electron injection at Ag29 NC/methyl viologen (MV2+) interfaces is very efficient and ultrafast. Interestingly, our femto- and nanosecond time-resolved results demonstrate clearly that both dynamic and static electron transfer mechanisms are involved in photoluminescence quenching of Ag29 NCs. © 2016 The Royal Society of Chemistry.

  2. Purification and characterization of the 3-chloro-4-hydroxy-phenylacetate reductive dehalogenase of Desulfitobacterium hafniense

    DEFF Research Database (Denmark)

    Christensen, Nina; Ahring, Birgitte Kiær; Wohlfarth, Gert

    1998-01-01

    The membrane-bound 3-chloro-4-hydroxyphenylacetate (Cl-OHPA) reductive dehalogenase from the chlorophenol- educing anaerobe Desulfitobacterium hafniense was purified 11.3-fold to apparent homogeneity in the presence of the detergent CHAPS. The purified dehalogenase catalyzed the reductive...... dechlorination of Cl-OHPA to 4-hydroxyphenylacetate with reduced methyl viologen as the electron donor at a specific activity of 103.2 nkat/mg protein. SDS-PAGErevealed a single protein band with an apparent molecular mass of 46.5 kDa. The enzyme contained 0.68±0.2 mol corrinoid, 12.0±0.7 mol iron, and 13...

  3. Fabrication, electrochemical and electrocatalytic properties of carbon nanotube@nano-SiO{sub 2}BenV/phosphomolybdic acid polynary nanocomposite materials

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiang; Wang, Jing; Wang, Wen-Bo [Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433 (China); Chen, Meng [Department of Material Science, Fudan University, 220 Handan Road, Shanghai 200433 (China); Qian, Dong-Jin, E-mail: djqian@fudan.edu.cn [Department of Chemistry, Fudan University, 220 Handan Road, Shanghai 200433 (China)

    2017-06-30

    Highlights: • Carbon nanotube@nano-SiO{sub 2}BenV(+86-21-65643666)/PMA polynary nanocomposites were prepared. • Functionalized silica nanoparticles covalently attached on the MWNT surfaces. • The nanocomposites showed reversible redox properties of viologen and PMA. • The nanocomposites acted as efficient heterogeneous catalysts for bromate reduction. - Abstract: Organic-inorganic nano-materials have attracted growing attention due to their potential applications for optoelectronic devices, sensors, and heterogeneous catalysts. We reported here on the preparation of polynary nanocomposites composed of poly(4-vinylpyridine) (P4VP) functionalized multi-walled carbon nanotubes (MWNTP4VP), silica nanoparticles (nano-SiO{sub 2}), viologens, and/or phosphomolybdic acid (PMA), in which the MWNTP4VP, nano-SiO{sub 2}, and viologens were covalently connected while PMA was electrostatically adsorbed. Thermogravimetric analysis revealed that the nanocomposites were composed of about 40–45% MWNTs, 40–45% nanoSiO{sub 2}, as well as 10–15% organic species and others. The preparation processes and compositions of the nanocomposites were characterized using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Field emission transmission electron microscopic images revealed that the nano-SiO{sub 2}BenV particles were strongly attached to the MWNTP4VP surfaces to form MWNTP4VP@nano-SiO{sub 2}BenV triad nano-cores. Cyclic voltammograms of the MWNTP4VP@nano-SiO{sub 2}BenV casting films showed three couples of redox waves in the potential range between −0.8 and 0 V (vs Ag/AgCl), designated to the electron transfer process of viologen substituents of MWNTP4VP@nano-SiO{sub 2}BenV{sup 2+} ↔ MWNTP4VP@nano-SiO{sub 2}BenV{sup +}· and their dimers. Further, three couples of redox waves were recorded for the casting films of MWNTP4VP@nano-SiO{sub 2}BenV/PMA polynary nanocomposites in the potential range between −0.2 and 0.8 V, designated to three

  4. Helquats, helical extended diquats, as fast electron transfer systems

    Czech Academy of Sciences Publication Activity Database

    Pospíšil, Lubomír; Teplý, Filip; Gál, Miroslav; Adriaenssens, Louis; Horáček, Michal; Severa, Lukáš

    2010-01-01

    Roč. 12, č. 7 (2010), s. 1550-1556 ISSN 1463-9076 R&D Projects: GA ČR GA203/09/0705; GA ČR GP203/09/P502; GA MŠk ME09114; GA MŠk OC 140 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40550506 Keywords : reversible redox systems * self-exchange kinetics * methyl viologen Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.454, year: 2010

  5. Ultrafast static and diffusion-controlled electron transfer at Ag 29 nanocluster/molecular acceptor interfaces

    KAUST Repository

    Aly, Shawkat Mohammede

    2015-10-29

    Efficient absorption of visible light and a long-lived excited state lifetime of silver nanoclusters (Ag29 NCs) are integral properties for these new clusters to serve as light-harvesting materials. Upon optical excitation, electron injection at Ag29 NC/methyl viologen (MV2+) interfaces is very efficient and ultrafast. Interestingly, our femto- and nanosecond time-resolved results demonstrate clearly that both dynamic and static electron transfer mechanisms are involved in photoluminescence quenching of Ag29 NCs. © 2016 The Royal Society of Chemistry.

  6. Experimental elaboration and analysis of dye-sensitized TiO2 solar cells (DSSC) dyed by natural dyes and conductive polymers

    Science.gov (United States)

    KałuŻyński, P.; Maciak, E.; Herzog, T.; Wójcik, M.

    2016-09-01

    In this paper we propose low cost and easy in development fully working dye-sensitized solar cell module made with use of a different sensitizing dyes (various anthocyanins and P3HT) for increasing the absorption spectrum, transparent conducting substrates (vaccum spattered chromium and gold), nanometer sized TiO2 film, iodide and methyl viologen dichloride based electrolyte, and a counter electrode (vaccum spattered platinum or carbon). Moreover, some of the different technologies and optimization manufacturing processes were elaborated for energy efficiency increase and were presented in this paper.

  7. Aqueous electrolytes for redox flow battery systems

    Science.gov (United States)

    Liu, Tianbiao; Li, Bin; Wei, Xiaoliang; Nie, Zimin; Wang, Wei; Liu, Jun; Sprenkle, Vincent L.

    2017-10-17

    An aqueous redox flow battery system includes an aqueous catholyte and an aqueous anolyte. The aqueous catholyte may comprise (i) an optionally substituted thiourea or a nitroxyl radical compound and (ii) a catholyte aqueous supporting solution. The aqueous anolyte may comprise (i) metal cations or a viologen compound and (ii) an anolyte aqueous supporting solution. The catholyte aqueous supporting solution and the anolyte aqueous supporting solution independently may comprise (i) a proton source, (ii) a halide source, or (iii) a proton source and a halide source.

  8. Photolytic and radiolytic studies of redox processes in aqueous solutions of acridine yellow

    International Nuclear Information System (INIS)

    Micic, O.I.; Nenadovic, M.T.

    1981-01-01

    Irradiation by visible light of an aqueous solution containing acridine yellow as a sensitizer and EDTA or cysteine as an electron donor leads to the formation of reduced species which can later reduce several different electron acceptors. Methyl viologen, europium(III) salicylate, europium(III) EDTA complex or vanadium(III) salicylate were used as electron acceptors. In the presence of a catalyst reduction of water is accompanied by the evolution of hydrogen. The kinetics and mechanism of redox reactions occurring in such a system have been explored by pulse radiolysis. Optimum conditions for water reduction under continuous illumination are analysed and implications for an energy conversion system discussed. (author)

  9. Sorption behaviour of herbicides in soils

    International Nuclear Information System (INIS)

    Luchini, L.C.; Wiendl, F.M.; Ruegg, E.F.; Instituto Biologico, Sao Paulo

    1988-01-01

    Environmental contamination by herbicides is related with the sorption phenomenon of these compounds in the soils. The behaviour of paraquat, 2,4-D and diuron was studied in soils with different physico-chemical properties, through the Freundlich adsorption and desorption isotherms, using 14 C-radiolabeled herbicides. Results of the range of the adsorption-desorption of each herbicide was related mainly with the chemical characteristics of these compounds. (author) [pt

  10. RNAi Mediated Silencing of LRRK2G2019S in Parkinson’s Disease

    Science.gov (United States)

    2013-08-01

    WT, but not LRRK2 mutant, protected 446 dopaminergic neurons against rotenone or paraquat toxicity, 447Q12 agents which compromise [52]. The...and animal models of G2019S-mediated neurotoxicity to establish a novel therapy for PD. To achieve this objective we proposed the following Specific...kinase domain (kinase dead mutants) diminishes neurotoxicity and basal kinase levels appear to be required for the toxicity of all LRRK2 mutants [6

  11. Mechanism for Prenatal LPS-Induced DA Neuron Loss

    Science.gov (United States)

    2006-09-01

    Neurol 355:479–489. rooks AI, Chadwick CA, Gelbard HA, Cory-Slechta DA, Federoff HJ (1999) Paraquat elicited neurobehavioral syndrome caused by do...Stadler, J., Chandran, J., Klinefelter , G. R., Blackstone, C., and Cookson, M. R. (2003) J. Biol. Chem. 278, 36588–36595 4. Macedo, M. G., Anar, B...fluctuations Reserpine induced a parkinsonism-like syndrome in some PROGRESSION IN PD 241 Table 2. Comparison of Human PD Characteristics With Animal Models

  12. Human neuromelanin: an endogenous microglial activator for dopaminergic neuron death

    OpenAIRE

    Zhang, Wei; Zecca, Luigi; Wilson, Belinda; Ren, RW; Wang, Yong-jun; Wang, Xiao-min; Hong, Jau-Shyong

    2013-01-01

    Substantial evidence indicates that neuroinflammation caused by over-activation of microglial in the substantia nigra is critical in the pathogenesis of dopaminergic neurodegeneration in Parkinson’s disease (PD). Increasing data demonstrates that environmental factors such as rotenone, paraquat play pivotal roles in the death of dopaminergic neurons. Here, potential role and mechanism of neuromelanin (NM), a major endogenous component in dopaminergic neurons of the substantia nigra, on microg...

  13. Toxicogenetics: in search of host susceptibility to environmental toxicants

    OpenAIRE

    Alam, Gelareh; Jones, Byron C.

    2014-01-01

    Heavy metals, various pesticide and herbicides are implicated as risk factors for human health. Paraquat, maneb, and rotenone, carbamate, and organophosphorous insecticides are examples of toxicants for which acute and chronic exposure are associated with multiple neurological disorders including Parkinson’s disease. Nevertheless, the role of pesticide exposure in neurodegenerative diseases is not clear-cut, as there are inconsistencies in both the epidemiological and preclinical research. Th...

  14. Isogenic Human iPSC Parkinson’s Model Shows Nitrosative Stress-Induced Dysfunction in MEF2-PGC1α Transcription

    OpenAIRE

    Ryan, Scott D.; Dolatabadi, Nima; Chan, Shing Fai; Zhang, Xiaofei; Akhtar, Mohd Waseem; Parker, James; Soldner, Frank; Sunico, Carmen R.; Nagar, Saumya; Talantova, Maria; Lee, Brian; Lopez, Kevin; Nutter, Anthony; Shan, Bing; Molokanova, Elena

    2013-01-01

    Parkinson’s disease (PD) is characterized by loss of A9 dopaminergic (DA) neurons in the substantia nigra pars compacta (SNpc). An association has been reported between PD and exposure to mitochondrial toxins, including environmental pesticides paraquat, maneb, and rotenone. Here, using a robust, patient-derived stem cell model of PD allowing comparison of A53T α-synuclein (α-syn) mutant cells and isogenic mutation-corrected controls, we identify mitochondrial toxin-induced perturbations in A...

  15. Natural toxins implicated in the development of Parkinson’s disease

    OpenAIRE

    Salama, Mohamed; Arias-Carrión, Oscar

    2011-01-01

    Experimental models of Parkinson’s disease (PD) are of great importance for improving the design of future clinical trials. Various neurotoxic models are available, including 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), paraquat and rotenone. However, no model is considered perfect; each has its own limitations. Based on epidemiological data, a new trend of using environmental toxins in PD modeling seems attractive and has dominated public discussions of th...

  16. A tristable [2]pseudo[2]rotaxane

    KAUST Repository

    Trabolsi, Ali

    2010-01-01

    A strategy towards increasing the lifetime of the metastable state of a [2]rotaxane incorporating tetrathiafulvalene, 1,5-dioxynaphthalene and bipyridinium (BIPY 2+) is presented. Incorporation of BIPY 2+ served multiple roles as an electrostatic barrier to relaxation, a supramolecular recognition site for bis-1,5-dioxynaphthalene[38]crown-10 macrocycle, and upon reduction a recognition site for the mechanically bonded cyclobis(paraquat-p-phenylene) ring. © The Royal Society of Chemistry 2010.

  17. pH-controlled quaternary ammonium herbicides capture/release by carboxymethyl-β-cyclodextrin functionalized magnetic adsorbents: Mechanisms and application

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Chang; Wang, Peng [Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193 (China); Shen, Zhigang [Zhong Nong Fa Seed Industry Group Co. Ltd, Beijing 600313 (China); Liu, Xueke; Zhou, Zhiqiang [Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193 (China); Liu, Donghui, E-mail: liudh@cau.edu.cn [Department of Applied Chemistry, China Agricultural University, No. 2 West Yuanmingyuan Road, Beijing 100193 (China)

    2015-12-11

    In our work, the pH-controlled magnetic solid phase extraction for the determination of paraquat and diquat was introduced firstly. Furthermore, to clarify the mechanism of carboxymethyl-β-cyclodextrin functionalized magnetic adsorbents, we studied the pH-responsive supramolecular interaction between carboxymethyl-β-cyclodextrin (CM-β-CD) and paraquat/diquat by ultraviolet–visible (UV–vis) spectroscopy and nuclear magnetic resonance (NMR) experiment, and the energy-minimized structures were also obtained. Then, the functional group CM-β-CD was modified on the surface of magnetic materials to synthesize the adsorbent. The Fourier transform infrared spectrum (FT-IR) results proved the successful modification of CM-β-CD. Thus, this absorbent was applied for the determination of paraquat and diquat in water. Under the optimal condition, limits of detection (LODs) of paraquat and diquat were 0.8 μg L{sup −1} and 0.9 μg L{sup −1}, relative standard deviations (RSD) and recoveries varied 0.7–4.6% and 86.5–106.6%, respectively. Good recoveries (70.2–100.0%) and low RSD (1.7–9.6%) were achieved in analyzing spiked water samples. Furthermore, with the capillary electrophoresis (CE) as the analyser, the whole analytical process did not need the attendance of organic solvents. - Highlights: • The carboxymethyl-β-cyclodextrin functionalized magnetic adsorbents were synthesized. • The adsorbents could capture or release quaternary ammonium herbicides by changing pH. • The adsorbents were applied in the analysis of real water samples. • There is no attendance of organic solvents in the whole analysis process.

  18. Effects of herbicides on /sup 14/CO/sub 2/ fixation in isolated mesophyll cells from Beta vulgaris (sugar beet) and Chenopodium album

    Energy Technology Data Exchange (ETDEWEB)

    Baumann, G; Guenther, G [Paedagogische Hochschule Karl Liebknecht, Potsdam (German Democratic Republic)

    1979-01-01

    10/sup -4/ - 10/sup -6/ molar solutions of herbicides (atrazine, 2,4-D, desmetryne, diallate, diquat, feuron, lenacil, NaTa, paraquat, phenmedipham, prometryne, propham, pyrazone, and simazine) cause similar inhibitory effects on the photosynthetic /sup 14/CO/sub 2/ fixation in isolated mesophyll cells from Chenopodium album and Beta vulgaris. Correlatdion between inhibition and herbicide resistance of the whole plants could be realized for lenacil only.

  19. Interaction of organic contaminants with natural clay type geosorbents: potential use as geologic barrier in urban landfill.

    Science.gov (United States)

    Sánchez-Jiménez, N; Sevilla, M T; Cuevas, J; Rodríguez, M; Procopio, J R

    2012-03-01

    The aim of this work is to characterize the capability of several clay materials as preservative of organic pollution for use as landfill barrier. Interaction of representative organic pollutants with different polarity and water solubility (atrazine, benzamide, methomyl, paraquat and toluene) with several clay materials coming from several locations of Spain were studied. Batch suspension method was used to study the pesticide adsorption onto the clay sorbents in solution conditions that simulate the composition of a young leachate in its aerobic acetogenic stage (pH=5 and I=0.15) The obtained data of the analytes sorption were modelized by several sorption isotherm models, and the best fitted data were got with a generalized Langmuir adsorption isotherm. The higher maxima adsorptions were observed for paraquat (50-62 mmol kg(-1)) and toluene (19-34 mmol kg(-1)) whereas more hydrophobic compounds present lower adsorption (0.7-2.5 mmol kg(-1)). Paraquat is the compound that presents the higher bonding coefficients. Therefore these clays could be used as components of the multibarriers in controlled urban landfill. Copyright © 2011 Elsevier Ltd. All rights reserved.

  20. Herbicidal treatments for control of Papaver somniferum L.

    Science.gov (United States)

    Horowitz, M

    1980-01-01

    Fifty-five commercially available herbicides were evaluated for possible use to destroy illicit opium poppy crops (Papaver somniferum). In the first stage, herbicides were sprayed on poppy plants grown in containers. The following compounds killed poppy plants: (a) herbicides with typical foliar activity--amitrole, bromoxynil, 2,4-D, glyphosate, ioxynil and paraquat; and (b) herbicides with root and foliar activity--the triazines ametryn, atrazine, metribuzin, prometryn, simazine and terbutryn; the substituted ureas benzthiazuron, chloroxuron, diuron, fluometuron, linuron, methabenzthiazuron, neburon and phenobenzuron; and the miscellaneous compounds karbutilate, methazole, oxadiazon and pyrazon. Severe but sublethal injury was caused by cycloate, EPTC, molinate, pobulate, cacodylate + MSMA, ethofumesate, perfluidone and phenmedipham. Abnormal development of vegetative or reproductive parts of the plant was induced by benefin, butralin, dinitramine, pendimethalin, trifluralin, diphenamid, napropamide, dalapon and propham. Efficient herbicides with negligible persistence in soil at the doses applied were evaluated on poppy plants in the field at various stages of growth. Small plants were severely injured by 2,4-D, killed rapidly by bromoxynil, ioxynil, paraquat (in mixture + diquat), and more slowly by glyphosate and metribuzin. The resistance to herbicides increased with the age of the poppy plant. Severe damage with partial kill of developed plants was obtained with bromoxynil, ioxynil, glyphosate, and paraquat + diquat; the last treatment produced the fastest effect.

  1. Non-targeted detection of chemical contamination in carbonated soft drinks using NMR spectroscopy, variable selection and chemometrics

    Energy Technology Data Exchange (ETDEWEB)

    Charlton, Adrian J. [Department for Environment, Food and Rural Affairs, Central Science Laboratory, Sand Hutton, York YO41 1LZ (United Kingdom)], E-mail: adrian.charlton@csl.gov.uk; Robb, Paul; Donarski, James A.; Godward, John [Department for Environment, Food and Rural Affairs, Central Science Laboratory, Sand Hutton, York YO41 1LZ (United Kingdom)

    2008-06-23

    An efficient method for detecting malicious and accidental contamination of foods has been developed using a combined {sup 1}H nuclear magnetic resonance (NMR) and chemometrics approach. The method has been demonstrated using a commercially available carbonated soft drink, as being capable of identifying atypical products and to identify contaminant resonances. Soft-independent modelling of class analogy (SIMCA) was used to compare {sup 1}H NMR profiles of genuine products (obtained from the manufacturer) against retail products spiked in the laboratory with impurities. The benefits of using feature selection for extracting contaminant NMR frequencies were also assessed. Using example impurities (paraquat, p-cresol and glyphosate) NMR spectra were analysed using multivariate methods resulting in detection limits of approximately 0.075, 0.2, and 0.06 mM for p-cresol, paraquat and glyphosate, respectively. These detection limits are shown to be approximately 100-fold lower than the minimum lethal dose for paraquat. The methodology presented here is used to assess the composition of complex matrices for the presence of contaminating molecules without a priori knowledge of the nature of potential contaminants. The ability to detect if a sample does not fit into the expected profile without recourse to multiple targeted analyses is a valuable tool for incident detection and forensic applications.

  2. Non-targeted detection of chemical contamination in carbonated soft drinks using NMR spectroscopy, variable selection and chemometrics

    International Nuclear Information System (INIS)

    Charlton, Adrian J.; Robb, Paul; Donarski, James A.; Godward, John

    2008-01-01

    An efficient method for detecting malicious and accidental contamination of foods has been developed using a combined 1 H nuclear magnetic resonance (NMR) and chemometrics approach. The method has been demonstrated using a commercially available carbonated soft drink, as being capable of identifying atypical products and to identify contaminant resonances. Soft-independent modelling of class analogy (SIMCA) was used to compare 1 H NMR profiles of genuine products (obtained from the manufacturer) against retail products spiked in the laboratory with impurities. The benefits of using feature selection for extracting contaminant NMR frequencies were also assessed. Using example impurities (paraquat, p-cresol and glyphosate) NMR spectra were analysed using multivariate methods resulting in detection limits of approximately 0.075, 0.2, and 0.06 mM for p-cresol, paraquat and glyphosate, respectively. These detection limits are shown to be approximately 100-fold lower than the minimum lethal dose for paraquat. The methodology presented here is used to assess the composition of complex matrices for the presence of contaminating molecules without a priori knowledge of the nature of potential contaminants. The ability to detect if a sample does not fit into the expected profile without recourse to multiple targeted analyses is a valuable tool for incident detection and forensic applications

  3. Detection of Colletotrichum acutatum Latent Infections in Strawberry Petioles and Leaves

    Directory of Open Access Journals (Sweden)

    Nataša Duduk

    2008-01-01

    Full Text Available Colletotrichum acutatum is the most significant agent of anthracnose strawberry fruit rot. Besides being a necrotrophic pest, it can spend a part of its life cycle as an epiphyte, in a form of latent infection. The presence of the fungi on symptomless plant tissue is considered one of the main ways of distribution of this economically harmful pathogen in the world. Investigation of latent C. acutatum infection was carried out on artificially inoculated strawberries. The initiation of fungi sporulation on symptomless petioles and leaves was carried out by exposing them to the herbicide paraquat (0.25% and low temperatures, which caused plant tissue decay in different ways. Surface sterilization with 0.5% NaOCl precedes the exposure of plant material to paraquat. The freezing procedure was carried out by exposure of plant material to the temperature of -20°C for 2h. After the freezing, one group was rinsed in Tween 20 (18 μl/l, and another group underwent surface sterilization in 0.0525% NaOCl with an addition of Tween 20 (18 μl/l. After 6 days of incubation, the appearance of acervuli and conidia was detected in 93.33 to 100% plant parts exposed to paraquat treatment and freezing procedure. In inoculated parts which were not exposed to herbicides or low temperatures, the presence of acervuli was detected in 3.33% tested petioles and 6.67% leaves.

  4. Effects of Commonly Used Pesticides in China on the Mitochondria and Ubiquitin-Proteasome System in Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Tingting Chen

    2017-11-01

    Full Text Available Evidence continues to accumulate that pesticides are the leading candidates of environmental toxins that may contribute to the pathogenesis of Parkinson’s disease. The mechanisms, however, remain largely unclear. According to epidemiological studies, we selected nine representative pesticides (paraquat, rotenone, chlorpyrifos, pendimethalin, endosulfan, fenpyroximate, tebufenpyrad, trichlorphon and carbaryl which are commonly used in China and detected the effects of the pesticides on mitochondria and ubiquitin-proteasome system (UPS function. Our results reveal that all the nine studied pesticides induce morphological changes of mitochondria at low concentrations. Paraquat, rotenone, chlorpyrifos, pendimethalin, endosulfan, fenpyroximate and tebufenpyrad induced mitochondria fragmentation. Furthermore, some of them (paraquat, rotenone, chlorpyrifos, fenpyroximate and tebufenpyrad caused a significant dose-dependent decrease of intracellular ATP. Interestingly, these pesticides which induce mitochondria dysfunction also inhibit 26S and 20S proteasome activity. However, two out of the nine pesticides, namely trichlorphon and carbaryl, were found not to cause mitochondrial fragmentation or functional damage, nor inhibit the activity of the proteasome, which provides significant guidance for selection of pesticides in China. Moreover, our results demonstrate a potential link between inhibition of mitochondria and the UPS, and pesticide-induced Parkinsonism.

  5. Electrocatalytic behahiour of cobalt tetraamino-phthalocyanine in the presence of a composite of reduced graphene nanosheets and of multi-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Nyoni, Stephen; Nyokong, Tebello

    2014-01-01

    Graphical abstract: A composite of multi-walled carbon nanotubes, reduced graphene nanosheets and cobalt tetraamino phthalocyanine was used for electrode modification, resulting in a rough surface as judged by scanning electrochemical microscopy. - Highlights: • Conjugates of multi-walled carbon nanotubes and reduced graphene nanosheets were used to modify glassy carbon electrode. • The electrode was further modified with cobalt tetraamino phthalocyanine. • The modified electrode was employed for the detection of paraquat. • A mechanism for paraquat detection using the composite electrodes is proposed. - Abstract: A composite of multi-walled carbon nanotubes (MWCNT) with reduced graphene nanosheets (rGNS-2) was developed in order to minimize the restacking of the latter. The composite was used to modify a glassy carbon electrode (GCE). GCE was further modified with cobalt tetraamino phthalocyanine (CoTAPc). The modified electrode is represented as rGNS-2-MWCNT-CoTAPc-GCE. X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electrochemical microscopy and Raman spectroscopy were used to explore into surface functionalities, morphology and topography of the nanocomposite. The rGNS-2-MWCNT-CoTAPc-GCE had a low limit of detection of 3.32 × 10 −8 M towards the detection of paraguat as a test analyte. A mechanism for paraquat detection using an rGNS-2-MWCNT-CoTAPc-GCE is also proposed in this work

  6. Protective glove use and hygiene habits modify the associations of specific pesticides with Parkinson’s disease

    Science.gov (United States)

    Furlong, Melissa; Tanner, Caroline M; Goldman, Samuel M; Bhudhikanok, Grace S.; Blair, Aaron; Chade, Anabel; Comyns, Kathleen; Hoppin, Jane A.; Kasten, Meike; Korell, Monica; Langston, J William; Marras, Connie; Meng, Cheryl; Richards, Marie; Ross, G Webster; Umbach, David M; Sandler, Dale P; Kamel, Freya

    2014-01-01

    Pesticides have been associated with Parkinson’s disease (PD), and protective gloves and workplace hygiene can reduce pesticide exposure. We assessed whether use of gloves and workplace hygiene modified associations between pesticides and PD. The Farming and Movement Evaluation (FAME) Study is a nested case-control study within the Agricultural Health Study. Use of protective gloves, other PPE, and hygiene practices were determined by questionnaire (69 cases and 237 controls were included). We considered interactions of gloves and hygiene with ever-use of pesticides for all pesticides with ≥ 5 exposed and unexposed cases and controls in each glove-use stratum (paraquat, permethrin, rotenone, and trifluralin). 61% of respondents consistently used protective gloves and 87% consistently used ≥ 2 hygiene practices. Protective glove use modified the associations of paraquat and permethrin with PD: neither pesticide was associated with PD among protective glove users, while both pesticides were associated with PD among non-users (paraquat OR 3.9 [95% CI 1.3, 11.7], interaction p=0.15; permethrin OR 4.3 [95% CI 1.2, 15.6] interaction p=0.05). Rotenone was associated with PD regardless of glove use. Trifluralin was associated with PD among people who used glove use and hygiene practices appeared to be important modifiers of the association between pesticides and PD and may reduce risk of PD associated with certain pesticides. PMID:25461423

  7. Weed Control and Peanut Tolerance with Ethalfluralin-Based Herbicide Systems

    Directory of Open Access Journals (Sweden)

    W. J. Grichar

    2012-01-01

    Full Text Available Field studies were conducted from 2007 through 2009 to determine weed efficacy and peanut (Arachis hypogaea L. response to herbicide systems that included ethalfluralin applied preplant incorporated. Control of devil's claw (Proboscidea louisianica (Mill. Thellung, yellow nutsedge (Cyperus esculentus L., Palmer amaranth (Amaranthus palmeri S. Wats., and puncturevine (Tribulus terrestris L. was most consistent with ethalfluralin followed by either imazapic or imazethapyr applied postemergence. Peanut stunting was 19% when paraquat alone was applied early-postemergence. Stunting increased to greater than 30% when ethalfluralin applied preplant incorporated was followed by S-metolachlor applied preemergence and paraquat applied early-postemergence. Stunting (7% was also observed when ethalfluralin was followed by flumioxazin plus S-metolachlor applied preemergence with lactofen applied mid-postemergence. Ethalfluralin followed by paraquat applied early-postemergence reduced peanut yield when compared to the nontreated check. Ethalfluralin applied preplant incorporated followed by imazapic applied mid-postemergence provided the greatest yield (6220 kg/ha. None of the herbicide treatments reduced peanut grade (sound mature kernels plus sound splits when compared with the nontreated check.

  8. Direct surface analysis of pesticides on soil, leaves, grass, and stainless steel by static secondary ion mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Ingram, J.C.; Groenewold, G.S.; Appelhans, A.D.; Delmore, J.E.; Olson, J.E.; Miller, D.L. [Idaho National Engineering Lab., Idaho Falls, ID (United States)

    1997-02-01

    Direct surface analyses by static secondary ion mass spectrometry (SIMS) were performed for the following pesticides adsorbed on dandelion leaves, grass, soil, and stainless steel samples: alachlor, atrazine, captan, carbofuran, chlorpyrifos, chlorosulfuron, chlorthal-dimethyl, cypermethrin, 2,4-D, diuron, glyphosate, malathion, methomyl, methyl arsonic acid, mocap, norflurazon, oxyfluorfen, paraquat, temik, and trifluralin. The purpose of this study was to evaluate static SIMS as a tool for pesticide analysis, principally for use in screening samples for pesticides. The advantage of direct surface analysis compared with conventional pesticide analysis methods is the elimination of sample pretreatment including extraction, which streamlines the analysis substantially; total analysis time for SIMS analysis was ca. 10 min/sample. Detection of 16 of the 20 pesticides on all four substrates was achieved. Of the remaining four pesticides, only one (trifluralin) was not detected on any of the samples. The minimum detectable quantity was determined for paraquat on soil in order to evaluate the efficacy of using SIMS as a screening tool. Paraquat was detected at 3 pg/mm{sup 2} (c.a. 0.005 monolayers). The results of these studies suggest that SIMS is capable of direct surface detection of a range of pesticides, with low volatility, polar pesticides being the most easily detected. 25 refs., 2 figs., 2 tabs.

  9. Purification and characterization of [Fe]-hydrogenase from high yielding hydrogen-producing strain, Enterobacter cloacae IIT-BT08 (MTCC 5373)

    Energy Technology Data Exchange (ETDEWEB)

    Dutta, Tumpa; Das, Amit Kumar; Das, Debabrata [Department of Biotechnology, Indian Institute of Technology, Kharagpur, WB 721302 (India)

    2009-09-15

    Fe-hydrogenase from Enterobacter cloacae IIT-BT08 was purified 1284 fold with specific activity of 335 {mu}mol H{sub 2}/min/mg protein for hydrogen evolution using reduced methyl viologen as an electron-donor at 25 C. The molecular weight of the monomeric enzyme was determined to be 51 kDa by MALDI-ToF mass spectrometry. The PI of the enzyme was {proportional_to}5.6 displaying its acidic nature. The optimal temperature and pH for hydrogen evolution was 37 C and 7-7.2 respectively. The affinity constant, K{sub m} for reduced methyl viologen was 0.57 {+-} 0.03 mM and that of reduced ferredoxin was 0.72 {+-} 0.04 {mu}M. The enzyme contained {proportional_to}11.47 gm-atom Fe/mol of Fe-hydrogenase. Electron paramagnetic resonance analysis ascertained the existence of iron molecules as [4Fe-4S] clusters. The internal amino acid sequences of trypsin digested peptides of hydrogenase as determined by ESI MS/MS Q-ToF showed 80-87% identities with the respective sequences of Clostridium sp. and Trichomonas sp. hydrogenase. (author)

  10. Development kinetics of silver clusters on silver halides

    International Nuclear Information System (INIS)

    Grzesiak, S.; Belloni, J.; Marignier, J.-L.

    2008-01-01

    Silver nuclei are produced by pulse radiolysis at the surface of AgCl nanocrystallites in the presence of an electron donor, the methyl viologen, which induces the growth of silver nuclei. The experimental results observed on the increase of the silver atom concentration and on the decay of the donor concentration during this process, which is similar to the photographic development by an electron donor, are compared with the kinetics obtained from numerical simulation. The model assumes that the formation of silver clusters with a supercritical nuclearity is required before the start of an electron transfer reaction from the two reduced forms of the donor methyl viologen to the silver clusters. The reaction is controlled by the access of the donor to the surface sites of the AgCl crystallite. The rate constant values of the successive steps of the mechanism are derived from the adjustment of calculated kinetics to experimental signals under various conditions, using a single set of parameters which are fairly suitable under all conditions studied

  11. Reduction of nitric oxide catalyzed by hydroxylamine oxidoreductase from an anammox bacterium.

    Science.gov (United States)

    Irisa, Tatsuya; Hira, Daisuke; Furukawa, Kenji; Fujii, Takao

    2014-12-01

    The hydroxylamine oxidoreductase (HAO) from the anammox bacterium, Candidatus Kuenenia stuttgartiensis has been reported to catalyze the oxidation of hydroxylamine (NH2OH) to nitric oxide (NO) by using bovine cytochrome c as an oxidant. In contrast, we investigated whether the HAO from anammox bacterium strain KSU-1 could catalyze the reduction of NO with reduced benzyl viologen (BVred) and the NO-releasing reagent, NOC 7. The reduction proceeded, resulting in the formation of NH2OH as a product. The oxidation rate of BVred was proportional to the concentration of BVred itself for a short period in each experiment, a situation that was termed quasi-steady state. The analyses of the states at various concentrations of HAO allowed us to determine the rate constant for the catalytic reaction, (2.85 ± 0.19) × 10(5) M(-1) s(-1), governing NO reduction by BVred and HAO, which was comparable to that reported for the HAO from the ammonium oxidizer, Nitrosomonas with reduced methyl viologen. These results suggest that the anammox HAO functions to adjust anammox by inter-conversion of NO and NH2OH depending on the redox potential of the physiological electron transfer protein in anammox bacteria. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  12. Physiology and enzymology involved in denitrification by Shewanella putrefaciens

    Science.gov (United States)

    Krause, B.; Nealson, K. H.

    1997-01-01

    Nitrate reduction to N2O was investigated in batch cultures of Shewanella putrefaciens MR-1, MR-4, and MR-7. All three strains reduced nitrate to nitrite to N2O, and this reduction was coupled to growth, whereas ammonium accumulation was very low (0 to 1 micromol liter-1). All S. putrefaciens isolates were also capable of reducing nitrate aerobically; under anaerobic conditions, nitrite levels were three- to sixfold higher than those found under oxic conditions. Nitrate reductase activities (31 to 60 micromol of nitrite min-1 mg of protein-1) detected in intact cells of S. putrefaciens were equal to or higher than those seen in Escherichia coli LE 392. Km values for nitrate reduction ranged from 12 mM for MR-1 to 1.3 mM for MR-4 with benzyl viologen as an artifical electron donor. Nitrate and nitrite reductase activities in cell-free preparations were demonstrated in native gels by using reduced benzyl viologen. Detergent treatment of crude and membrane extracts suggested that the nitrate reductases of MR-1 and MR-4 are membrane bound. When the nitrate reductase in MR-1 was partially purified, three subunits (90, 70, and 55 kDa) were detected in denaturing gels. The nitrite reductase of MR-1 is also membrane bound and appeared as a 60-kDa band in sodium dodecyl sulfate-polyacrylamide gels after partial purification.

  13. Fabrication of hydrogenase-cationic electrolyte biohybrids at interfaces and their electrochemical properties in Langmuir-Blodgett films

    International Nuclear Information System (INIS)

    Liu An; Zorin, Nikolay A.; Nakamura, Chikashi; Miyake, Jun; Qian Dongjin

    2010-01-01

    Hydrogenase (H 2 ase)-cationic electrolyte biohybrids were assembled at the air-water interface via intermolecular electrostatic interaction. The H 2 ase used was purified from the phototropic bacterium of Thiocapsa roseopersicina. Two kinds of cationic electrolyte compounds (CECs) were used, the difference of which was whether they contained viologen substituent or not. Surface pressure-area isotherms indicated that these CECs were co-existed with the H 2 ase in the monolayers, which were then transferred to substrate surfaces to form H 2 ase-CECs hybrid films by the Langmuir-Blodgett (LB) method. Uniform film was formed when polyelectrolyte was used as the subphase. Cyclic voltammograms (CVs) of the LB films showed a couple of redox waves in the potential range of -0.4 to -0.65 V vs. Ag/AgCl, which was ascribed to one electron process of either [4Fe-4S] clusters of H 2 ase or viologens of the CECs. A direct electron transfer between the H 2 ase and electrode surface was achieved in the LB films. Stronger current intensity was recorded when the CV measurements were done in H 2 saturated electrolyte solution than that in Ar. It was confirmed that the H 2 ase biocatalytic activity remained in the LB films. Thus, we suggest that the present H 2 ase-CECs biohybrids could act as potential materials for the studies of interconversion reaction of H 2 and protons.

  14. Grafting of antibacterial polymers on stainless steel via surface-initiated atom transfer radical polymerization for inhibiting biocorrosion by Desulfovibrio desulfuricans.

    Science.gov (United States)

    Yuan, S J; Xu, F J; Pehkonen, S O; Ting, Y P; Neoh, K G; Kang, E T

    2009-06-01

    To enhance the biocorrosion resistance of stainless steel (SS) and to impart its surface with bactericidal function for inhibiting bacterial adhesion and biofilm formation, well-defined functional polymer brushes were grafted via surface-initiated atom transfer radical polymerization (ATRP) from SS substrates. The trichlorosilane coupling agent, containing the alkyl halide ATRP initiator, was first immobilized on the hydroxylated SS (SS-OH) substrates for surface-initiated ATRP of (2-dimethylamino)ethyl methacrylate (DMAEMA). The tertiary amino groups of covalently immobilized DMAEMA polymer or P(DMAEMA), brushes on the SS substrates were quaternized with benzyl halide to produce the biocidal functionality. Alternatively, covalent coupling of viologen moieties to the tertiary amino groups of P(DMAEMA) brushes on the SS surface resulted in an increase in surface concentration of quaternary ammonium groups, accompanied by substantially enhanced antibacterial and anticorrosion capabilities against Desulfovibrio desulfuricans in anaerobic seawater, as revealed by antibacterial assay and electrochemical studies. With the inherent advantages of high corrosion resistance of SS, and the good antibacterial and anticorrosion capabilities of the viologen-quaternized P(DMAEMA) brushes, the functionalized SS is potentially useful in harsh seawater environments and for desalination plants. Copyright 2009 Wiley Periodicals, Inc.

  15. Evaluation of electrode surface modification techniques for the development of chemical sensors

    International Nuclear Information System (INIS)

    Galiatsatos, C.

    1988-01-01

    This thesis covers several aspects of electrode surface modification techniques. The successful application of gamma-radiation to create polymer-coated electrodes, where the polymers can be ion exchangers and consequently of great analytical interest by themselves (such as the polymer poly(diallyl) dimethyl ammonium chloride) or where some other neutral polymers can function as convenient matrices for the introduction of biomolecules and/or other electrochemically interesting species is reported. This is demonstrated by using the neutral polymer poly(vinyl alcohol) (PVAL) as a matrix for immobilization of the enzyme glucose oxidase and the mediator methyl viologen. The effect of γ-radiation on PVAL is discussed, as well as swelling properties of the irradiated polymers and specific characteristics of the created chemical sensors. Results of an experiment where the various kinds of interactions between the ion-exchange polymer Nafion and some positively charged species are explored are reported, and a model system for competition (methyl viologen vs. ruthenium hexaamine) which increases significantly our understanding of the interaction is mentioned. The effect of γ-radiation on Nafion and its ion-exchange compabilities is discussed also. A system of conduction polymers primarily polypyrrole, used as a detector of electroinactive anions due to their doping-undergoing in the film is discussed. Preliminary results on a new method that involves chemical cross-linking of a triisocyane molecule with -OH containing polymers in the presence of enzymes are reported

  16. Electron transfer between a zinc porphyrin photo-sensitized in the visible, and various acceptors, in aqueous and micellar solutions

    International Nuclear Information System (INIS)

    Le Roux, Dominique

    1983-01-01

    This research thesis addresses the study of reactions occurring during the transformation of solar energy in chemical energy, and more precisely the search for photochemical systems allowing the dissociation of water into hydrogen and oxygen. In this study on water photolysis, the author chose to use a porphyrin soluble in water, the zinc tetra-meta-N-methylpyridinium porphyrin, as one of its isomer provided a good efficiency in hydrogen formation. Before reporting the study of electron photo-transfer, the author reports the study of photo-physical and photochemical properties of this porphyrin. Then, in the case of a well known electron acceptor (methyl viologen), he studied the influence of Coulomb effects on the kinetics of direct electron transfer, and on the kinetics of recombination of formed species. He also studied the influence of organised systems (cationic micelles) on these reactions when using a viologen with long chains. He finally reports the study of reactions of the triplet state of this porphyrin with metallic complexes

  17. Improvement of the butanol production selectivity and butanol to acetone ratio (B:A) by addition of electron carriers in the batch culture of a new local isolate of Clostridium acetobutylicum YM1.

    Science.gov (United States)

    Nasser Al-Shorgani, Najeeb Kaid; Kalil, Mohd Sahaid; Wan Yusoff, Wan Mohtar; Shukor, Hafiza; Hamid, Aidil Abdul

    2015-12-01

    Improvement in the butanol production selectivity or enhanced butanol:acetone ratio (B:A) is desirable in acetone-butanol-ethanol (ABE) fermentation by Clostridium strains. In this study, artificial electron carriers were added to the fermentation medium of a new isolate of Clostridium acetobutylicum YM1 in order to improve the butanol yield and B:A ratio. The results revealed that medium supplementation with electron carriers changed the metabolism flux of electron and carbon in ABE fermentation by YM1. A decrease in acetone production, which subsequently improved the B:A ratio, was observed. Further improvement in the butanol production and B:A ratios were obtained when the fermentation medium was supplemented with butyric acid. The maximum butanol production (18.20 ± 1.38 g/L) was gained when a combination of methyl red and butyric acid was added. Although the addition of benzyl viologen (0.1 mM) and butyric acid resulted in high a B:A ratio of 16:1 (800% increment compared with the conventional 2:1 ratio), the addition of benzyl viologen to the culture after 4 h resulted in the production of 18.05 g/L butanol. Manipulating the metabolic flux to butanol through the addition of electron carriers could become an alternative strategy to achieve higher butanol productivity and improve the B:A ratio. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Avaliação da eficiência de herbicidas no controle de plantas daninhas em alfafa Decreasing of weed plants using herbicides and herbicides mix in alfalfa crop

    Directory of Open Access Journals (Sweden)

    Wilson da Silva

    2004-08-01

    Full Text Available Objetivou-se neste trabalho avaliar a seletividade e a eficiência de herbicidas no controle de plantas daninhas na cultura da alfafa. Foram desenvolvidos dois experimentos em Anápolis, GO. No primeiro, avaliaram-se oito herbicidas (imazethapyr, MSMA, fomesafen, bentazon, chlorimuron-ethyl, imazamox aplicados em pós-emergência da alfafa, e no segundo, seis misturas de herbicidas [(diuron + MSMA, (diuron + MSMA, (diuron + paraquat, (diuron + paraquat] aplicados um dia após o corte da alfafa. Em ambos os experimentos, foram incluídas duas testemunhas (capinada e sem capina, sendo os tratamentos distribuídos em blocos ao acaso com quatro repetições. Os herbicidas como imazethapyr, MSMA, fomesafen, bentazon, chlorimuron-ethyl e imazamox foram seletivos à cultura da alfafa e eficientes no controle de plantas daninhas. As misturas dos herbicidas (diuron + MSMA e (diuron + paraquat aplicados logo após o corte da alfafa causaram danos às folhas e aos caules remanescentes. As brotações, todavia, surgiram isentas de toxicidade, apresentando crescimento e desenvolvimento normais. Essas misturas promoveram eficiente controle de plantas daninhas, e não afetaram o acúmulo de biomassa seca e altura de plantas em relação à testemunha capinada. O não-controle das plantas daninhas reduziu a produção de biomassa seca e a altura das plantas de alfafa em 74,5% e 42,8%, respectivamente.The objectives of this study were to evaluate the efficiency and selectivity of herbicides on the weed plants control at the alfalfa crop. Two experiments were carried out at the Experimental Station of Agenciarural, located in Anápolis, GO. In the first experiment it was evaluated eight herbicides (imazethapyr, MSMA, fomesafen, bentazon, chlorimuron-ethyl and imazamox post emergency and in the second experiment six different mixed of herbicides [(diuron + MSMA, (diuron + MSMA, (diuron + paraquat, (diuron + paraquat] applied one day after the alfalfa harvesting

  19. Manejo de Conyza bonariensis resistente ao glyphosate: coberturas de inverno e herbicidas em pré-semeadura da soja Management of glyphosate resistant Conyza bonariensis: winter cover crops and herbicides in soybean pre-seeding

    Directory of Open Access Journals (Sweden)

    F.P. Lamego

    2013-06-01

    Full Text Available Conyza bonariensis tornou-se a principal planta daninha da cultura da soja no Sul do Brasil, em decorrência da evolução para resistência ao herbicida glyphosate. O objetivo deste trabalho foi avaliar o efeito de diferentes coberturas de inverno e da associação de manejo de dessecação pré-semeadura da soja, visando ao controle de C. bonariensis resistente ao glyphosate. Um experimento foi conduzido em campo, na safra 2010/2011. Os tratamentos foram conduzidos em esquema de parcelas subdivididas, em que as coberturas de inverno foram alocadas nas parcelas principais: aveia-preta, nabo, ervilhaca, azevém, trigo e pousio. Nas subparcelas, foram alocados os tratamentos de manejo de dessecação pré-semeadura da soja: glyphosate (720 g e.a ha-1, glyphosate (720 g e.a ha-1 + 2,4-D (1.050 g e.a ha-1, glyphosate (720 g e.a ha-1 + 2,4-D (1.050 g e.a ha-1/paraquat (200 g i.a ha-1 + diuron (100 g i.a ha-1, glyphosate (720 g e.a ha-1 + chlorimuron-ethyl (80 g i.a ha-1, glyphosate (720 g e.a ha-1 + chlorimuron-ethyl (80 g i.a ha-1/paraquat (200 g i.a ha-1 + diuron (100 g i.a ha‑1 e roçada. O nabo foi a espécie de cobertura que produziu o maior volume de massa seca durante o inverno, enquanto a ervilhaca foi a que apresentou maior efeito supressor sobre a germinação e o desenvolvimento inicial de C. bonariensis. Associações de glyphosate com 2,4-D ou chlorimuron-ethyl, seguidas da aplicação sequencial de paraquat + diuron, causaram maior redução na infestação de C. bonariensis.Conyza bonariensis became the main weed in soybean crop in Southern Brazil, as a consequence of the evolution of resistance to the herbicide glyphosate. The objective of this work was to evaluate the effect of different winter cover crops and the association of burn-down herbicides on the control of glyphosate-resistant C. bonariensis. A field experiment was conducted in the 2010/2011 season. The treatments were arranged in a split-plot scheme, with the winter

  20. Effect of herbicides on desiccation of Lolium multiflorum L. plants and seed germinationEfeito de herbicidas na dessecação e germinação de sementes remanescentes de Lolium multiflorum L.

    Directory of Open Access Journals (Sweden)

    Caio Ferraz de Campos

    2012-12-01

    Full Text Available A trial was carried out to evaluate efficacy of different herbicides and spray volumes when sprayed to ryegrass for chemical management and control of remaining seeds. The treatments were: three formulations of glyphosate at 1080 g ha-1 (Original Round up, Round up Transorb, WG Round Up, paraquat + diuron at 300+500 and 150+250 g ha-1 and glufosinate ammonium at 400 and 600 g ha-1. All treatments were used in spray volumes of 200 and 400 l ha-1. The effectiveness of the desiccation of ryegrass plants was assessed at 1, 3, 7, 14 and 21 days after application. At the last evaluation samples were collected for dry mass production analysis, and also panicles with seeds for germination test. Glyphosate in different formulations and volumes and glufosinate ammonium at 600 g ha-1 when sprayed with into 400 l ha-1 provided the best controls regarding ryegrass chemical management. Treatments with gliphosate (Roundup Original and paraquat + diuron (300 +150 g ha-1 in volumes of 400 and 200 L ha-1, respectively, were the ones that showed the lowest values of dry matter, differing from the control. All the ryegrass seeds were killed by treatments with herbicides (paraquat + diuron at 500 +250 g ha-1 and glufosinate-ammonium at 600 g ha-1 when used 200 l ha-1. O objetivo desse trabalho foi o de avaliar a eficácia de diferentes herbicidas aplicados em pósemergência na dessecação de plantas de azevém e viabilidade de sementes remanescentes do controle, com diferentes volumes de calda de aplicação. Os tratamentos testados foram: três formulações de glyphosate na dose de 1.080g ha-1 (Roundup Original, Roundup Transorb, Roundup WG, paraquat + diuron nas doses de 300 + 150 e 500 + 250g ha-1 e amônio-glufosinate nas doses de 400 e 600g ha-1. Em todos os tratamentos foram utilizados os volumes de aplicação de 200 e 400L ha-1. A eficácia na dessecação de plantas de azevém foram avaliados aos 1, 3, 7, 14 e 21 dias após aplicação, sendo que nesta

  1. Acute effects of a prooxidant herbicide on the microalga Chlamydomonas reinhardtii: Screening cytotoxicity and genotoxicity endpoints

    International Nuclear Information System (INIS)

    Esperanza, Marta; Cid, Ángeles; Herrero, Concepción; Rioboo, Carmen

    2015-01-01

    Highlights: • Mitochondrial membrane potential constituted the most sensitive parameter assayed. • Several genotoxicity methods were applied for first time in ecotoxicological studies. • Oxidative DNA base damage (8-OHdG) was induced by paraquat exposure. • Cells with DNA strand breakage and subG1-nuclei increased in treated cultures. • Typical apoptosis hallmarks were observed in microalgal cells exposed to paraquat. - Abstract: Since recent evidence has demonstrated that many types of chemicals exhibit oxidative and/or genotoxic potential on living organisms, reactive oxygen species (ROS) formation and DNA damage are currently the best accepted paradigms to assess the potential hazardous biological effects of a wide range of contaminants. The goal of this study was to evaluate the sensitivity of different cytotoxicity and genotoxicity responses on the model microalga Chlamydomonas reinhardtii exposed to the prooxidant herbicide paraquat. In addition to the growth endpoint, cell viability, mitochondrial membrane potential and presence of reactive oxygen species (ROS) were assayed as potential markers of cytotoxicity using flow cytometry (FCM). To study the effects of paraquat on C. reinhardtii DNA, several genotoxicity approaches were implemented for the first time in an ecotoxicological study on microalgae. Oxidative DNA base damage was analysed by measuring the oxidative DNA lesion 8-OHdG by FCM. DNA fragmentation was analysed by different methods: comet assay, and cell cycle analysis by FCM, with a particular focus on the presence of subG1-nuclei. Finally, effects on morphology of nuclei were monitored through DAPI staining. The evaluation of these endpoints showed that several physiological and biochemical parameters reacted to oxidative stress disturbances with greater sensitivity than integrative parameters such as growth rates or cell viability. The experiments revealed concentration-dependent cytotoxicity (ROS formation, depolarization of

  2. Acute effects of a prooxidant herbicide on the microalga Chlamydomonas reinhardtii: Screening cytotoxicity and genotoxicity endpoints

    Energy Technology Data Exchange (ETDEWEB)

    Esperanza, Marta; Cid, Ángeles; Herrero, Concepción; Rioboo, Carmen, E-mail: carmen.rioboo@udc.es

    2015-08-15

    Highlights: • Mitochondrial membrane potential constituted the most sensitive parameter assayed. • Several genotoxicity methods were applied for first time in ecotoxicological studies. • Oxidative DNA base damage (8-OHdG) was induced by paraquat exposure. • Cells with DNA strand breakage and subG1-nuclei increased in treated cultures. • Typical apoptosis hallmarks were observed in microalgal cells exposed to paraquat. - Abstract: Since recent evidence has demonstrated that many types of chemicals exhibit oxidative and/or genotoxic potential on living organisms, reactive oxygen species (ROS) formation and DNA damage are currently the best accepted paradigms to assess the potential hazardous biological effects of a wide range of contaminants. The goal of this study was to evaluate the sensitivity of different cytotoxicity and genotoxicity responses on the model microalga Chlamydomonas reinhardtii exposed to the prooxidant herbicide paraquat. In addition to the growth endpoint, cell viability, mitochondrial membrane potential and presence of reactive oxygen species (ROS) were assayed as potential markers of cytotoxicity using flow cytometry (FCM). To study the effects of paraquat on C. reinhardtii DNA, several genotoxicity approaches were implemented for the first time in an ecotoxicological study on microalgae. Oxidative DNA base damage was analysed by measuring the oxidative DNA lesion 8-OHdG by FCM. DNA fragmentation was analysed by different methods: comet assay, and cell cycle analysis by FCM, with a particular focus on the presence of subG1-nuclei. Finally, effects on morphology of nuclei were monitored through DAPI staining. The evaluation of these endpoints showed that several physiological and biochemical parameters reacted to oxidative stress disturbances with greater sensitivity than integrative parameters such as growth rates or cell viability. The experiments revealed concentration-dependent cytotoxicity (ROS formation, depolarization of

  3. Reproductive organ and vascular specific promoter of the rice plasma membrane Ca2+ATPase mediates environmental stress responses in plants.

    Directory of Open Access Journals (Sweden)

    Kazi Md Kamrul Huda

    Full Text Available Plasma membrane Ca(2+ATPase is a transport protein in the plasma membrane of cells and helps in removal of calcium (Ca(2+ from the cell, hence regulating Ca(2+ level within cells. Though plant Ca(2+ATPases have been shown to be involved in plant stress responses but their promoter regions have not been well studied.The 1478 bp promoter sequence of rice plasma membrane Ca(2+ATPase contains cis-acting elements responsive to stresses and plant hormones. To identify the functional region, serial deletions of the promoter were fused with the GUS sequence and four constructs were obtained. These were differentially activated under NaCl, PEG cold, methyl viologen, abscisic acid and methyl jasmonate treatments. We demonstrated that the rice plasma membrane Ca(2+ATPase promoter is responsible for vascular-specific and multiple stress-inducible gene expression. Only full-length promoter showed specific GUS expression under stress conditions in floral parts. High GUS activity was observed in roots with all the promoter constructs. The -1478 to -886 bp flanking region responded well upon treatment with salt and drought. Only the full-length promoter presented cold-induced GUS expression in leaves, while in shoots slight expression was observed for -1210 and -886 bp flanking region. The -1210 bp deletion significantly responded to exogenous methyl viologen and abscisic acid induction. The -1210 and -886 bp flanking region resulted in increased GUS activity in leaves under methyl jasmonate treatments, whereas in shoots the -886 bp and -519 bp deletion gave higher expression. Salicylic acid failed to induce GUS activities in leaves for all the constructs.The rice plasma membrane Ca(2+ATPase promoter is a reproductive organ-specific as well as vascular-specific. This promoter contains drought, salt, cold, methyl viologen, abscisic acid and methyl jasmonate related cis-elements, which regulated gene expression. Overall, the tissue-specificity and inducible

  4. Presentations of patients of poisoning and predictors of poisoning-related fatality: Findings from a hospital-based prospective study

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    Lin Hung-Jung

    2008-01-01

    Full Text Available Abstract Background Poisoning is a significant public health problem worldwide and is one of the most common reasons for visiting emergency departments (EDs, but factors that help to predict overall poisoning-related fatality have rarely been elucidated. Using 1512 subjects from a hospital-based study, we sought to describe the demographic and clinical characteristics of poisoning patients and to identify predictors for poisoning-related fatality. Methods Between January 2001 and December 2002 we prospectively recruited poisoning patients through the EDs of two medical centers in southwest Taiwan. Interviews were conducted with patients within 24 hours after admission to collect relevant information. We made comparisons between survival and fatality cases, and used logistic regressions to identify predictors of fatality. Results A total of 1512 poisoning cases were recorded at the EDs during the study period, corresponding to an average of 4.2 poisonings per 1000 ED visits. These cases involved 828 women and 684 men with a mean age of 38.8 years, although most patients were between 19 and 50 years old (66.8%, and 29.4% were 19 to 30 years. Drugs were the dominant poisoning agents involved (49.9%, followed by pesticides (14.5%. Of the 1512 patients, 63 fatalities (4.2% occurred. Paraquat exposure was associated with an extremely high fatality rate (72.1%. The significant predictors for fatality included age over 61 years, insufficient respiration, shock status, abnormal heart rate, abnormal body temperature, suicidal intent and paraquat exposure. Conclusion In addition to well-recognized risk factors for fatality in clinical settings, such as old age and abnormal vital signs, we found that suicidal intent and ingestion of paraquat were significant predictors of poisoning-related fatality. Identification of these predictors may help risk stratification and the development of preventive interventions.

  5. Novel Phosphorylation and Ubiquitination Sites Regulate Reactive Oxygen Species-dependent Degradation of Anti-apoptotic c-FLIP Protein*

    Science.gov (United States)

    Wilkie-Grantham, Rachel P.; Matsuzawa, Shu-Ichi; Reed, John C.

    2013-01-01

    The cytosolic protein c-FLIP (cellular Fas-associated death domain-like interleukin 1β-converting enzyme inhibitory protein) is an inhibitor of death receptor-mediated apoptosis that is up-regulated in a variety of cancers, contributing to apoptosis resistance. Several compounds found to restore sensitivity of cancer cells to TRAIL, a TNF family death ligand with promising therapeutic potential, act by targeting c-FLIP ubiquitination and degradation by the proteasome. The generation of reactive oxygen species (ROS) has been implicated in c-FLIP protein degradation. However, the mechanism by which ROS post-transcriptionally regulate c-FLIP protein levels is not well understood. We show here that treatment of prostate cancer PPC-1 cells with the superoxide generators menadione, paraquat, or buthionine sulfoximine down-regulates c-FLIP long (c-FLIPL) protein levels, which is prevented by the proteasome inhibitor MG132. Furthermore, pretreatment of PPC-1 cells with a ROS scavenger prevented ubiquitination and loss of c-FLIPL protein induced by menadione or paraquat. We identified lysine 167 as a novel ubiquitination site of c-FLIPL important for ROS-dependent degradation. We also identified threonine 166 as a novel phosphorylation site and demonstrate that Thr-166 phosphorylation is required for ROS-induced Lys-167 ubiquitination. The mutation of either Thr-166 or Lys-167 was sufficient to stabilize c-FLIP protein levels in PPC-1, HEK293T, and HeLa cancer cells treated with menadione or paraquat. Accordingly, expression of c-FLIP T166A or K167R mutants protected cells from ROS-mediated sensitization to TRAIL-induced cell death. Our findings reveal novel ROS-dependent post-translational modifications of the c-FLIP protein that regulate its stability, thus impacting sensitivity of cancer cells to TRAIL. PMID:23519470

  6. Preparation of H3PW12O40/MCM-48 and its photocatalytic degradation of pesticides.

    Science.gov (United States)

    Liu, Xia; Li, Yan-zhou; Gan, Qiang; Feng, Chang-gen

    2014-08-01

    A composite catalyst H3PW12O40/MCM-48 was prepared by loading photocatalyst phosphotungstic acid H3PW12O40 (HPW) to molecular sieve MCM-48 by impregnation method, and its structure was characterized by Fourier transform infrared (FT-IR) spectra, small angle X-ray diffraction (XRD) patterns, nitrogen adsorption analysis and High-resolution transmission electron microscopy (HRTEM) analysis. Photocatalytic degradation activities of HPW/MCM-48 against pesticides imidacloprid and paraquat were evaluated under UV radiation (365 nm). The results show that HPW/MCM-48 maintains the mesoprous molecular sieve structure of MCM-48 and the Keggin structure of HPW, while the BET surface area is 793.35 m2 x g(-1), pore volume is 1.46 cm3 x g(-1), average pore diameter is 2.76 nm, suggesting loading HPW on MCM-48 is a considerable way to improve its surface area. After 14 h UV irradiation (365 nm), 57.38% imidacloprid and 63.79% paraquat were degraded by 20 mg HPW/MCM-48 catalyst, while HPW and blank group degraded the two pesticides at the degradation rate of about 25% and 5%, respectively. Implying loading on MCM-48 could greaterly improve the degradation activity of HPW. The reslut of degradation kinetics show that, the degradation process of HPW/MCM-48 fits first order kinetics equation. The rate constant Ka of HPW/MCM-48 toward imidacloprid and paraquat are 0.089 h and 0.117 h, with the half-life t(1/2) of 7.8 h and 5.9 h, respectively.

  7. Specific pesticide-dependent increases in α-synuclein levels in human neuroblastoma (SH-SY5Y) and melanoma (SK-MEL-2) cell lines.

    Science.gov (United States)

    Chorfa, Areski; Bétemps, Dominique; Morignat, Eric; Lazizzera, Corinne; Hogeveen, Kevin; Andrieu, Thibault; Baron, Thierry

    2013-06-01

    Epidemiological studies indicate a role of genetic and environmental factors in Parkinson's disease involving alterations of the neuronal α-synuclein (α-syn) protein. In particular, a relationship between Parkinson's disease and occupational exposure to pesticides has been repeatedly suggested. Our objective was to precisely assess changes in α-syn levels in human neuroblastoma (SH-SY5Y) and melanoma (SK-MEL-2) cell lines following acute exposure to pesticides (rotenone, paraquat, maneb, and glyphosate) using Western blot and flow cytometry. These human cell lines express α-syn endogenously, and overexpression of α-syn (wild type or mutated A53T) can be obtained following recombinant adenoviral transduction. We found that endogenous α-syn levels in the SH-SY5Y neuroblastoma cell line were markedly increased by paraquat, and to a lesser extent by rotenone and maneb, but not by glyphosate. Rotenone also clearly increased endogenous α-syn levels in the SK-MEL-2 melanoma cell line. In the SH-SY5Y cell line, similar differences were observed in the α-syn adenovirus-transduced cells, with a higher increase of the A53T mutated protein. Paraquat markedly increased α-syn in the SK-MEL-2 adenovirus-transduced cell line, similarly for the wild-type or A53T proteins. The observed differences in the propensities of pesticides to increase α-syn levels are in agreement with numerous reports that indicate a potential role of exposure to certain pesticides in the development of Parkinson's disease. Our data support the hypothesis that pesticides can trigger some molecular events involved in this disease and also in malignant melanoma that consistently shows a significant but still unexplained association with Parkinson's disease.

  8. Recombinational micro-evolution of functionally different metallothionein promoter alleles from Orchesella cincta

    Directory of Open Access Journals (Sweden)

    van Straalen Nico M

    2007-06-01

    Full Text Available Abstract Background Metallothionein (mt transcription is elevated in heavy metal tolerant field populations of Orchesella cincta (Collembola. This suggests that natural selection acts on transcriptional regulation of mt in springtails at sites where cadmium (Cd levels in soil reach toxic values This study investigates the nature and the evolutionary origin of polymorphisms in the metallothionein promoter (pmt and their functional significance for mt expression. Results We sequenced approximately 1600 bp upstream the mt coding region by genome walking. Nine pmt alleles were discovered in NW-European populations. They differ in the number of some indels, consensus transcription factor binding sites and core promoter elements. Extensive recombination events between some of the alleles can be inferred from the alignment. A deviation from neutral expectations was detected in a cadmium tolerant population, pointing towards balancing selection on some promoter stretches. Luciferase constructs were made from the most abundant alleles, and responses to Cd, paraquat (oxidative stress inducer and moulting hormone were studied in cell lines. By using paraquat we were able to dissect the effect of oxidative stress from the Cd specific effect, and extensive differences in mt induction levels between these two stressors were observed. Conclusion The pmt alleles evolved by a number of recombination events, and exhibited differential inducibilities by Cd, paraquat and molting hormone. In a tolerant population from a metal contaminated site, promoter allele frequencies differed significantly from a reference site and nucleotide polymorphisms in some promoter stretches deviated from neutral expectations, revealing a signature of balancing selection. Our results suggest that the structural differences in the Orchesella cincta metallothionein promoter alleles contribute to the metallothionein -over-expresser phenotype in cadmium tolerant populations.

  9. Protection by extra virgin olive oil against oxidative stress in vitro and in vivo. Chemical and biological studies on the health benefits due to a major component of the Mediterranean diet

    Science.gov (United States)

    Rossi, Miriam; Kwok, Lorraine; Lee, Grace; Caruso, Alessio; Gionfra, Fabio; Candelotti, Elena; Belli, Stuart L.; Molasky, Nora; Raley-Susman, Kathleen M.; Leone, Stefano; Filipský, Tomáš; Tofani, Daniela; Pedersen, Jens; Incerpi, Sandra

    2017-01-01

    We report the results of in vivo studies in Caenorhabditis elegans nematodes in which addition of extra virgin olive oil (EVOO) to their diet significantly increased their life span with respect to the control group. Furthermore, when nematodes were exposed to the pesticide paraquat, they started to die after two days, but after the addition of EVOO to their diet, both survival percentage and lifespans of paraquat-exposed nematodes increased. Since paraquat is associated with superoxide radical production, a test for scavenging this radical was performed using cyclovoltammetry and the EVOO efficiently scavenged the superoxide. Thus, a linear correlation (y = -0.0838x +19.73, regression factor = 0.99348) was observed for superoxide presence (y) in the voltaic cell as a function of aliquot (x) additions of EVOO, 10 μL each. The originally generated supoeroxide was approximately halved after 10 aliquots (100 μL total). The superoxide scavenging ability was analyzed, theoretically, using Density Functional Theory for tyrosol and hydroxytyrosol, two components of EVOO and was also confirmed experimentally for the galvinoxyl radical, using Electron Paramagnetic Resonance (EPR) spectroscopy. The galvinoxyl signal disappeared after adding 1 μL of EVOO to the EPR cell in 10 minutes. In addition, EVOO significantly decreased the proliferation of human leukemic THP-1 cells, while it kept the proliferation at about normal levels in rat L6 myoblasts, a non-tumoral skeletal muscle cell line. The protection due to EVOO was also assessed in L6 cells and THP-1 exposed to the radical generator cumene hydroperoxide, in which cell viability was reduced. Also in this case the oxidative stress was ameliorated by EVOO, in line with results obtained with tetrazolium dye reduction assays, cell cycle analysis and reactive oxygen species measurements. We ascribe these beneficial effects to EVOO antioxidant properties and our results are in agreement with a clear health benefit of EVOO use

  10. Heart tissue of harlequin (hq)/Big Blue mice has elevated reactive oxygen species without significant impact on the frequency and nature of point mutations in nuclear DNA

    Energy Technology Data Exchange (ETDEWEB)

    Crabbe, Rory A. [Department of Biology, University of Western Ontario, London, Ontario, N6A 5B7 (Canada); Hill, Kathleen A., E-mail: khill22@uwo.ca [Department of Biology, University of Western Ontario, London, Ontario, N6A 5B7 (Canada)

    2010-09-10

    Age is a major risk factor for heart disease, and cardiac aging is characterized by elevated mitochondrial reactive oxygen species (ROS) with compromised mitochondrial and nuclear DNA integrity. To assess links between increased ROS levels and mutations, we examined in situ levels of ROS and cII mutation frequency, pattern and spectrum in the heart of harlequin (hq)/Big Blue mice. The hq mouse is a model of premature aging with mitochondrial dysfunction and increased risk of oxidative stress-induced heart disease with the means for in vivo mutation detection. The hq mutation produces a significant downregulation in the X-linked apoptosis-inducing factor gene (Aif) impairing both the antioxidant and oxidative phosphorylation functions of AIF. Brain and skin of hq disease mice have elevated frequencies of point mutations in nuclear DNA and histopathology characterized by cell loss. Reports of associated elevations in ROS in brain and skin have mixed results. Herein, heart in situ ROS levels were elevated in hq disease compared to AIF-proficient mice (p < 0.0001) yet, mutation frequency and pattern were similar in hq disease, hq carrier and AIF-proficient mice. Heart cII mutations were also assessed 15 days following an acute exposure to an exogenous ROS inducer (10 mg paraquat/kg). Acute paraquat exposure with a short mutant manifestation period was insufficient to elevate mutation frequency or alter mutation pattern in the post-mitotic heart tissue of AIF-proficient mice. Paraquat induction of ROS requires mitochondrial complex I and thus is likely compromised in hq mice. Results of this preliminary survey and the context of recent literature suggest that determining causal links between AIF deficiency and the premature aging phenotypes of specific tissues is better addressed with assay of mitochondrial ROS and large-scale changes in mitochondrial DNA in specific cell types.

  11. Heart tissue of harlequin (hq)/Big Blue mice has elevated reactive oxygen species without significant impact on the frequency and nature of point mutations in nuclear DNA

    International Nuclear Information System (INIS)

    Crabbe, Rory A.; Hill, Kathleen A.

    2010-01-01

    Age is a major risk factor for heart disease, and cardiac aging is characterized by elevated mitochondrial reactive oxygen species (ROS) with compromised mitochondrial and nuclear DNA integrity. To assess links between increased ROS levels and mutations, we examined in situ levels of ROS and cII mutation frequency, pattern and spectrum in the heart of harlequin (hq)/Big Blue mice. The hq mouse is a model of premature aging with mitochondrial dysfunction and increased risk of oxidative stress-induced heart disease with the means for in vivo mutation detection. The hq mutation produces a significant downregulation in the X-linked apoptosis-inducing factor gene (Aif) impairing both the antioxidant and oxidative phosphorylation functions of AIF. Brain and skin of hq disease mice have elevated frequencies of point mutations in nuclear DNA and histopathology characterized by cell loss. Reports of associated elevations in ROS in brain and skin have mixed results. Herein, heart in situ ROS levels were elevated in hq disease compared to AIF-proficient mice (p < 0.0001) yet, mutation frequency and pattern were similar in hq disease, hq carrier and AIF-proficient mice. Heart cII mutations were also assessed 15 days following an acute exposure to an exogenous ROS inducer (10 mg paraquat/kg). Acute paraquat exposure with a short mutant manifestation period was insufficient to elevate mutation frequency or alter mutation pattern in the post-mitotic heart tissue of AIF-proficient mice. Paraquat induction of ROS requires mitochondrial complex I and thus is likely compromised in hq mice. Results of this preliminary survey and the context of recent literature suggest that determining causal links between AIF deficiency and the premature aging phenotypes of specific tissues is better addressed with assay of mitochondrial ROS and large-scale changes in mitochondrial DNA in specific cell types.

  12. Protection by extra virgin olive oil against oxidative stress in vitro and in vivo. Chemical and biological studies on the health benefits due to a major component of the Mediterranean diet.

    Directory of Open Access Journals (Sweden)

    Miriam Rossi

    Full Text Available We report the results of in vivo studies in Caenorhabditis elegans nematodes in which addition of extra virgin olive oil (EVOO to their diet significantly increased their life span with respect to the control group. Furthermore, when nematodes were exposed to the pesticide paraquat, they started to die after two days, but after the addition of EVOO to their diet, both survival percentage and lifespans of paraquat-exposed nematodes increased. Since paraquat is associated with superoxide radical production, a test for scavenging this radical was performed using cyclovoltammetry and the EVOO efficiently scavenged the superoxide. Thus, a linear correlation (y = -0.0838x +19.73, regression factor = 0.99348 was observed for superoxide presence (y in the voltaic cell as a function of aliquot (x additions of EVOO, 10 μL each. The originally generated supoeroxide was approximately halved after 10 aliquots (100 μL total. The superoxide scavenging ability was analyzed, theoretically, using Density Functional Theory for tyrosol and hydroxytyrosol, two components of EVOO and was also confirmed experimentally for the galvinoxyl radical, using Electron Paramagnetic Resonance (EPR spectroscopy. The galvinoxyl signal disappeared after adding 1 μL of EVOO to the EPR cell in 10 minutes. In addition, EVOO significantly decreased the proliferation of human leukemic THP-1 cells, while it kept the proliferation at about normal levels in rat L6 myoblasts, a non-tumoral skeletal muscle cell line. The protection due to EVOO was also assessed in L6 cells and THP-1 exposed to the radical generator cumene hydroperoxide, in which cell viability was reduced. Also in this case the oxidative stress was ameliorated by EVOO, in line with results obtained with tetrazolium dye reduction assays, cell cycle analysis and reactive oxygen species measurements. We ascribe these beneficial effects to EVOO antioxidant properties and our results are in agreement with a clear health

  13. Aplicação de dessecantes na cultura de soja: antecipação da colheita e produção de sementes Application of desiccants on soybean crop glycine max: harvest anticipation and seed yield

    Directory of Open Access Journals (Sweden)

    A.L.S. Lacerda

    2001-12-01

    Full Text Available Este trabalho foi conduzido no município de Selvíria-MS, semeando soja do cultivar IAC-15. O delineamento experimental utilizado foi o de blocos casualizados, estando os tratamentos dispostos em um esquema fatorial 3x3 e 4x4, sendo os fatores os produtos (dessecantes e as épocas de aplicação, nos anos agrícolas 1996/97 e 1997/98, respectivamente. Os dessecantes utilizados foram: paraquat, diquat e mistura paraquat + diquat, nas dosagens de 0,4; 0,3 e 0,2+0,15 em 1996/97, respectivamente, e os mesmos tratamentos em 1997/98, além do glufosinato de amônio na dosagem de 0,4 kg i.a. ha-1 em 1997/98. Como épocas, foram realizadas três aplicações em 1996/97 e quatro em 1997/98, todas espaçadas de cinco dias a partir do estádio fenológico médio da cultura R6. Concluiu-se que os dessecantes utilizados mostraram-se eficientes na dessecação da soja; foi possível obter antecipação da colheita de sementes de soja, sem alterar a produção, por um período máximo de sete dias.This research was carried out in Selvíria-MS, Brazil, during the growing seasons of 1996/97 and 1997/98, using the soybean cultivar IAC-15. The experimental design was arranged in randomized complete blocks in a 3x3 and 4x4 factorial scheme during 1996/97 and 1997/98, respectively, with the factors being the products (desiccants and timing of application. The desiccants sprayed were: paraquat, diquat and a mixture of paraquat + diquat at rates of 0.4; 0.3 and 0.2+0.15 in 1996/97 and the same treatments in 1997/98 added to ammonium glufosinate at 0.4 kg a.i. ha-1 in 1997/98. The timing of application was spaced every five days, starting from the soybean vegetative stage R6. The tested desiccants were efficient on the soybean desiccation ; it was possible to obtain grain harvest anticipation, without yield reduction, in a maximum period of seven days.

  14. Eficácia de herbicidas no controle de plantas daninhas na cultura da cebola em semeadura direta Efficacy of herbicides on weed control in onion direct sowing

    Directory of Open Access Journals (Sweden)

    Lino R. Ferreira

    1999-04-01

    Full Text Available As plantas de cebola provenientes da semeadura direta no campo são mais danificadas pelo cultivo mecânico e são mais sensíveis aos herbicidas, principalmente os latifolicidas, do que quando transplantadas. Com o objetivo de avaliar a eficácia dos herbicidas oxyfluorfen, ioxynil-octanoato e fluazifop-p-butil, aplicados em pós-emergência, isoladamente ou em mistura no tanque, com ou sem aplicação de paraquat, antes da emergência das plantas de cebola, conduziu-se este trabalho no município de Monte Alto, SP. Nenhum dos herbicidas aplicados isoladamente foi eficiente no controle de todas as espécies daninhas presentes na área experimental. As misturas no tanque de fluazifop-p-butil com oxyfluorfen ou ioxynil-octanoato, independente da aplicação ou não de paraquat aos cinco dias após a semeadura, controlaram eficientemente Portulaca oleracea, Amaranthus lividus, Echinochloa crusgalli, Eragrostis pilosa, Digitaria horizontalis, Eleusine indica e Brachiaria plantaginea, com produção de bulbos semelhante à da testemunha capinada.Onion plants, from direct sowing to the field, are more damaged by mechanical cultivation and more sensitive to herbicides, especially to broadleaf herbicides, than transplanted onions. With the purpose of evaluating the efficacy of the herbicides oxyfluorfen, ioxynyl-octanoato and fluazifop-p-butyl, applied in post-emergence, alone or tank mix, with or without paraquat application, before onion plants emergence, this investigation was carried out at Monte Alto County, São Paulo State, Brazil. None of the herbicides sprayed alone were efficient in the control of all the weeds present in the experimental area. The tank mix of fluazifop-p-butyl plus oxyfluorfen or ioxynyl-octanoato, regardless of paraquat application, at five days after sowing, controlled efficiently Portulaca oleracea, Amaranthus lividus, Echinoclhoa crusgalli, Eragrostis pilosa, Digitaria horizontalis, Eleusine indica and Brachiaria

  15. Response of soil microbiota to selected herbicide treatments.

    Science.gov (United States)

    Roslycky, E B

    1977-04-01

    Recommended concentrations of paraquat alone and its combination with each of linuron, diuron, atrazine, simazine, and simazine plus diuron exerted little effect on total populations of bacteria, actinomycetes, and fungi in Fox sandy loam under laboratory and simulated field conditions in 66 and 77 days, respectively. Respiration of the total microbiota in soil suspension was afeected by the combinations as well as individual herbicides in various concentrations. Yet, the inhibition of the O2 uptake by any of these herbicides, including some extreme concentrations, was not permanent, indicating adaptation, or suppression of specific organisms. Only linuron in concentrations up to 20 microng/ml stimulated respiration of the soil.

  16. Pesticide residues and microbial contamination of water resources in the MUDA rice agroecosystem

    International Nuclear Information System (INIS)

    Cheah Uan Boh; Lum Keng Yeang

    2002-01-01

    Studies on the water resources of the Muda rice growing areas revealed evidence of pesticide residues in the agroecosystem. While the cyclodiene endosulfan was found as a ubiquitous contaminant, the occurrence of other organochlorine insecticides was sporadic. The presence of 2,4-D, paraquat and molinate residues was also evident but the occurrence of these herbicides was seasonal. Residue levels of molinate were generally higher than those from the other herbicides. The problem of thiobencarb and carbofuran residues was not encountered. Analyses for microbial contamination revealed that the water resources were unfit for drinking; coliform counts were higher during certain periods of the year than others. (Author)

  17. Lung function and airway inflammation in rats following exposure to combustion products of carbon-graphite/epoxy composite material: comparison to a rodent model of acute lung injury.

    Science.gov (United States)

    Whitehead, Gregory S; Grasman, Keith A; Kimmel, Edgar C

    2003-02-01

    Pulmonary function and inflammation in the lungs of rodents exposed by inhalation to carbon/graphite/epoxy advanced composite material (ACM) combustion products were compared to that of a rodent model of acute lung injury (ALI) produced by pneumotoxic paraquat dichloride. This investigation was undertaken to determine if short-term exposure to ACM smoke induces ALI; and to determine if smoke-related responses were similar to the pathogenic mechanisms of a model of lung vascular injury. We examined the time-course for mechanical lung function, infiltration of inflammatory cells into the lung, and the expression of three inflammatory cytokines, tumor necrosis factor-alpha (TNF-alpha), macrophage inflammatory protein-2 (MIP-2) and interferon-gamma (IFN-gamma). Male Fischer-344 rats were either exposed to 26.8-29.8 g/m(3) nominal concentrations of smoke or were given i.p. injections of paraquat dichloride. Measurements were determined at 1, 2, 3, and 7 days post exposure. In the smoke-challenged rats, there were no changes in lung function indicative of ALI throughout the 7-day observation period, despite the acute lethality of the smoke atmosphere. However, the animals showed signs of pulmonary inflammation. The expression of TNF-alpha was significantly increased in the lavage fluid 1 day following exposure, which preceded the maximum leukocyte infiltration. MIP-2 levels were significantly increased in lavage fluid at days 2, 3, and 7. This followed the leukocyte infiltration. IFN-gamma was significantly increased in the lung tissue at day 7, which occurred during the resolution of the inflammatory response. The paraquat, which was also lethal to a small percentage of the animals, caused several physiologic changes characteristic of ALI, including significant decreases in lung compliance, lung volumes/capacities, distribution of ventilation, and gas exchange capacity. The expression of TNF-alpha and MIP-2 increased significantly in the lung tissue as well as in the

  18. Non-nitro radiation sensitizers

    International Nuclear Information System (INIS)

    Jacobs, G.P.

    1986-01-01

    This short communication aims to update the review of non-nitro radiation sensitizers (Shenoy and Singh 1985) and correct omissions. Work is mentioned and bibliography given for studied of cis-platinum, potassium permanganate, cobalt hexammine, sodium bromide, dimethylsulphoxide, zinc and copper ions, organic nitroxyl free radicals (TAN,TMPN and NPPN + PNAP), halogenated pyrimidines, organic and inorganic iodine containing compounds, diacetyl, acetone and acetophenone, rho-hydrobenzoic acid and its esters, pentobarbitone and secobarbitone, heparin and 9-anilinoacridines, dehydropiandosterone and paraquat. (U.K.)

  19. Gene Expression of Type VI Secretion System Associated with Environmental Survival in Acidovorax avenae subsp. avenae by Principle Component Analysis

    OpenAIRE

    Cui, Zhouqi; Jin, Guoqiang; Li, Bin; Kakar, Kaleem; Ojaghian, Mohammad; Wang, Yangli; Xie, Guanlin; Sun, Guochang

    2015-01-01

    Valine glycine repeat G (VgrG) proteins are regarded as one of two effectors of Type VI secretion system (T6SS) which is a complex multi-component secretion system. In this study, potential biological roles of T6SS structural and VgrG genes in a rice bacterial pathogen, Acidovorax avenae subsp. avenae (Aaa) RS-1, were evaluated under seven stress conditions using principle component analysis of gene expression. The results showed that growth of the pathogen was reduced by H2O2 and paraquat-i...

  20. Embryotoxicita a indukce oxidativního stresu po exposici herbicidu paraquatu na modelovém necílovém organismu drápatce vodní (Xenopus laevis)

    Czech Academy of Sciences Publication Activity Database

    Pašková, Veronika; Hilscherová, Klára

    2007-01-01

    Roč. 43, č. 3 (2007), s. 107-112 ISSN 0007-389X. [Toxicita a biodegradabilita odpadů a látek významných ve vodním prostředí /13./. Vodňany, 18.06.2007-20.06.2007] R&D Projects: GA MŠk(CZ) 1M0571 Institutional research plan: CEZ:AV0Z60050516 Keywords : paraquat * oxidative stress * frogs Subject RIV: EF - Botanics

  1. Bioelectrochemical Haber-Bosch Process: An Ammonia-Producing H2 /N2 Fuel Cell.

    Science.gov (United States)

    Milton, Ross D; Cai, Rong; Abdellaoui, Sofiene; Leech, Dónal; De Lacey, Antonio L; Pita, Marcos; Minteer, Shelley D

    2017-03-01

    Nitrogenases are the only enzymes known to reduce molecular nitrogen (N 2 ) to ammonia (NH 3 ). By using methyl viologen (N,N'-dimethyl-4,4'-bipyridinium) to shuttle electrons to nitrogenase, N 2 reduction to NH 3 can be mediated at an electrode surface. The coupling of this nitrogenase cathode with a bioanode that utilizes the enzyme hydrogenase to oxidize molecular hydrogen (H 2 ) results in an enzymatic fuel cell (EFC) that is able to produce NH 3 from H 2 and N 2 while simultaneously producing an electrical current. To demonstrate this, a charge of 60 mC was passed across H 2  /N 2 EFCs, which resulted in the formation of 286 nmol NH 3  mg -1 MoFe protein, corresponding to a Faradaic efficiency of 26.4 %. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Oxidation reactions catalyzed by cobalt ions in a photocatalytic system based on solutions of lecit hin vesicles

    International Nuclear Information System (INIS)

    Tsvetkov, I.M.; Lymar, S.V.; Parmon, V.N.; Zamaraev, V.I.

    1986-01-01

    The features of the light-induced transfer of electrons through the membranes of lecithin vesicles with an electron carrier, viz., cetyl viologen, incorporated in the lipid bilayer have been studied with the use of the water-soluble trisbipyridyl complex of ruthenium (II) as a photocatalyst. It has been shown that additions of cobalt ions to the systems just indicated are capable of catalyzing the oxidation processes of organic compounds (most probably, of lecithin), the role of the oxidizing agent being played by Ru(bpy) 3 3+ , which forms upon the transfer of an electron to the acceptor Fe(CN) 6 3- through the lipid membrane The possibility of the utilization of the photocatalytic oxidation of water to oxygen under the action of visible light has been discussed

  3. Temperature impact on the primary radiolysis yields concerning the hydrous electron

    International Nuclear Information System (INIS)

    Baldacchino, G.; Vigneron, G.; Pommeret, St.

    2005-01-01

    We have studied the impact of temperature on the water radiolysis formation rate of the hydrous electron in presence of selenate di-anion SeO 4 2+ . We have used a high temperature (up to 500 Celsius degrees) optical cell coupled to the electron accelerator Alienor. It appears that the capture of the hydrous electron by selenate follows an Arrhenius law till the sub-critical range, beyond this range the kinetics of the reaction seems more erratic. We have also studied the capture of the hydrous electron by methyl-viologen (MV 2+ ) at 20 and 380 Celsius degrees. It seems that at high temperature more hydrous electrons are produced, it might be interpreted as a consequence of the shift toward the right of the following equilibrium reaction: OH - + H . ↔ e - (aq) + H 2 O. All these results need to be confirmed. (A.C.)

  4. Photoproduction of hydrogen by membranes of green photosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, J D; Olson, J M

    1980-01-01

    Photoproduction of H/sub 2/ from ascorbate by unit-membrane vesicles from Chlorobium limicola f. thiosulfatophilum was achieved with a system containing gramicidin D, tetramethyl-p-phenylenediamine, methyl viologen, dithioerythritol, Clostridium hydrogenase, and an oxygen-scavenging mixture of glucose, glucose oxidase, ethanol, and catalase. Maximum quantum yield was less than one percent. Half maximum rate of H/sub 2/ production occurred at a white-light intensity of approximately 0.15 cm/sup -2/. The reaction was inhibited completely by 0.3% sodium dodecylbenzene sulfonate, 1% Triton X-100, or preheating the vesicles at 100/sup 0/C for 5 minutes. Low concentrations (0.01 and 0.05%) of Triton X-100 about doubled the reaction rate.

  5. Hydrogen production by several cyanobacteria

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Dhruv; Kumar, H.D. (Banaras Hindu Univ., Varanasi (India). Dept. of Botany)

    1992-11-01

    Twenty species belonging to eleven genera of nitrogen-fixing and non-nitrogen-fixing cyanobacteria were screened for production of hydrogen. Only one species each of Nostoc and Anabaena showed light-and nitrogenase-dependent aerobic hydrogen production. The highest rate of aerobic hydrogen production was recorded in Anabaena sp. strain CA. When incubated anaerobically under 99% Ar + 1% CO[sub 2], all the tested strains produced hydrogen. Nickel supplementation completely abolished hydrogen production both under aerobic and anaerobic conditions, except in Anabaena sp. strain CA, where only the rate of production was decreased. Species of Plectonema, Oscillatoria and Spirulina showed methyl viologen-dependent (hydrogenase-dependent) hydrogen production. Other physiological activities were also studied with a view to selecting a suitable organism for large-scale production of hydrogen. (author)

  6. Binding of poly(amidoamine), carbosilane, phosphorus and hybrid dendrimers to thrombin-Constants and mechanisms.

    Science.gov (United States)

    Shcharbin, Dzmitry; Pedziwiatr-Werbicka, Elzbieta; Vcherashniaya, Aliaksandra; Janaszewska, Anna; Marcinkowska, Monika; Goska, Piotr; Klajnert-Maculewicz, Barbara; Ionov, Maksim; Abashkin, Viktar; Ihnatsyeu-Kachan, Aliaksei; de la Mata, F Javier; Ortega, Paula; Gomez-Ramirez, Rafael; Majoral, Jean-Pierre; Bryszewska, Maria

    2017-07-01

    Thrombin is an essential part of the blood coagulation system; it is a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, and catalyzes many other coagulation-related reactions. Absorption at its surface of small nanoparticles can completely change the biological properties of thrombin. We have analyzed the influence on thrombin of 3 different kinds of small nanoparticles: dendrimers (phosphorus-based, carbosilane based and polyamidoamine) and 2 hybrid systems containing carbosilane, viologen and phosphorus dendritic scaffolds in one single molecule, bearing different flexibility, size and surface charge. There was significant alteration in the rigidity of the rigid dendrimers in contrast to flexible dendrimers. These differences in their action are important in understanding interactions taking place at a bio-nanointerface. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Reduction of nitrogen oxides by gamma-irradiated hemoproteins. Pt. 2. Reduction of nitrite by immobilized gamma-irradiated hemoprotein

    International Nuclear Information System (INIS)

    Oku, Tadatake; Sato, Hitoshi; Ichikawa, Yoshinobu; Kaneko, Junko; Goto, Mituhiro; Nishio, Toshiyuki; Ito, Teiichiro; Kume, Tamikazu.

    1994-01-01

    Sodium and potassium nitrites are used for coloration and pasteurization of meat products as food additives. Recently, removal of nitrite in water has been one of the research area in environmental science because of the necessity of reducing water pollution. The horse cardiac cytochrome c in 0.1mM aqueous solution was denatured by gamma-irradiation at a dose of 10kGy in the presence of air, and was immobilized by lattice entrapment method in the polyacrylamide gel. The immobilized irradiated cytochrome c was reacted with nitrite in the presence of reducing agent (sodium hydrosulfite) and electron carrier (methyl viologen) at 30degC. The remaining nitrite was determined by diazo-reaction. Immobilized irradiated cytochrome c could be used as a substituent of nitrite reductase, and especially high nitrite reducing activity under nitrogen atmosphere in acidic range, and entrapment in 15% gel made possible to reuse denatured cytochrome c several times. (J.P.N.)

  8. Gold work function reduction by 2.2 eV with an air-stable molecular donor layer

    Energy Technology Data Exchange (ETDEWEB)

    Broeker, Benjamin; Blum, Ralf-Peter; Frisch, Johannes; Rabe, Juergen P.; Koch, Norbert [Institut fuer Physik, Humboldt-Universitaet zu Berlin (Germany); Vollmer, Antje [Berliner Elektronenspeicherring-Gesellschaft fuer Synchrotronstrahlung mbH, Berlin (Germany); Hofmann, Oliver T.; Zojer, Egbert [Institut of Solid State Physics, Graz University of Technology (Austria); Rieger, Ralph; Muellen, Klaus [Max Planck Institut fuer Polymerforschung, Mainz (Germany)

    2009-07-01

    Ultraviolet photoelectron spectroscopy was used to investigate neutral methyl viologen (1,1'-dimethyl-1H,1'H-[4,4']bipyridinylidene, MV0) deposited on Au(111) surfaces. As a result of molecule-to-metal electron transfer, the work function of Au(111) was decreased from 5.5 eV to 3.3 eV. The energy levels of electron transport layers deposited on top of modified Au surfaces were shifted to higher binding energy compared to layers on pristine Au, and the electron injection barrier was reduced by 0.8 eV for tris(8-hydroxyquinoline)aluminum (Alq3) and by 0.7 eV for C60. The air-stable donor MV0 can thus be used to facilitate electron injection into organic semiconductors even from high work function metals.

  9. Efficient photocatalytic hydrogen production from water over Pt-Eosin Y catalyst: A systemic study of reaction parameters

    Science.gov (United States)

    Wang, Li; Zhao, Hui; Chen, Yong; Sun, Ruimin; Han, Bing

    2016-07-01

    A high efficient homogeneous system for hydrogen production from water consisting of Eosin Y as a photosensitizer, methyl viologen (MV2+) as an electron transfer mediator, triethanolamine (TEOA) as a sacrificial electron donor and colloid Pt as a catalyst, has been systemicly studied. The initial system pH and the concentration of Eosin Y have remarkable effects on the rate of hydrogen evolution. The optimal pH and concentration of Eosin Y are 9 and 7.2×10-5 M. Triethanolamine (TEOA) as an electron donor, can reductively quench the oxidized Eosin Y and the quenching is well modeled by the Stern-Volmer equation. The optimal concentration of TEOA and the concentration of MV2+ are 0.3 M and 3.1×10-4 M, respectively. In addition, the role of colloid Pt has been investigated.

  10. Supracolloidal Architectures Self-Assembled in Microdroplets.

    Science.gov (United States)

    Xu, Xuejiao; Tian, Feng; Liu, Xin; Parker, Richard M; Lan, Yang; Wu, Yuchao; Yu, Ziyi; Scherman, Oren A; Abell, Chris

    2015-10-26

    We demonstrate a novel method for the formation of a library of structured colloidal assemblies by exploiting the supramolecular heteroternary host-guest interaction between cucurbit[8]uril (CB[8]) and methyl viologen- and naphthalene-functionalised particles. The approach is dependent upon compartmentalisation in microdroplets generated by a microfluidic platform. Though the distribution of colloidal particles encapsulated within each microdroplet followed a Poisson distribution, tuning the concentration of the initial colloidal particle suspensions provided some level of control over the structure of the formed colloidal assemblies. This ability to direct the assembly of complementarily-functionalised colloids through a supramolecular interaction, without the need for complex modification of the colloidal surface or external stimuli, presents an exciting new approach towards the design of structured colloidal materials with the potential to produce many challenging structures. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Synthesis of Dimethyl-Substituted Polyviologen and Control of Charge Transport in Electrodes for High-Resolution Electrochromic Displays

    Directory of Open Access Journals (Sweden)

    Kan Sato

    2017-03-01

    Full Text Available Electrochromic (EC polymers such as polyviologens have been attracting considerable attention as wet-processable electrodes for EC displays, thanks to their brilliant color change accompanied with reversible redox reactions. To establish wider usage, achieving multicolor and high-resolution characteristics is indispensable. In this paper, we demonstrated that the introduction of substituents such as methyl groups into bipyridine units changed the stereostructure of the cation radicals, and thus shifted the color (e.g., ordinary purple to blue. Also, by relaxing excessive π-stacking between the viologen moieties, the response rate was improved by a factor of more than 10. The controlled charge transport throughout the polyviologen layer gave rise to the fabrication of EC displays which are potentially suitable for the thin film transistor (TFT substrate as the counter electrodes with submillimeter pixels. The findings can be versatilely used for the new design of polyviologens with enhanced electrochemical properties and high-resolution, multicolor EC displays.

  12. Alumina plate containing photosystem I reaction center complex oriented inside plate-penetrating silica nanopores.

    Science.gov (United States)

    Kamidaki, Chihiro; Kondo, Toru; Noji, Tomoyasu; Itoh, Tetsuji; Yamaguchi, Akira; Itoh, Shigeru

    2013-08-22

    The photosynthetic photosystem I reaction center complex (PSI-RC), which has a molecular diameter of 21 nm with 100 pigments, was incorporated into silica nanopores with a 100-nm diameter that penetrates an alumina plate of 60-μm thickness to make up an inorganic-biological hybrid photocell. PSI-RCs, purified from a thermophilic cyanobacterium, were stable inside the nanopores and rapidly photoreduced a mediator dye methyl viologen. The reduced dye was more stable inside nanopores suggesting the decrease of dissolved oxygen. The analysis by a cryogenic electron spin paramagnetic resonance indicated the oriented arrangement of RCs inside the 100-nm nanopores, with their surface parallel to the silica wall and perpendicular to the plane of the alumina plate. PSI RC complex in the semicrystalline orientation inside silica nanopores can be a new type of light energy conversion unit to supply strong reducing power selectively to other molecules inside or outside nanopores.

  13. Enzymic oxidation of carbon monoxide. II

    Energy Technology Data Exchange (ETDEWEB)

    Yagi, T

    1959-01-01

    An enzyme which catalyzes the oxidation of carbon monoxide into carbon dioxide was obtained in a cell free state from Desulfovibrio desulfuricans. The enzyme activity was assayed manometrically by measuring the rate of gas uptake under the atmosphere of carbon monoxide in the presence of benzyl-viologen as an oxidant. The optimum pH range was 7 to 8. The activity was slightly suppressed by illumination. The enzyme was more stable than hydrogenase or formate dehydrogenase against the heat treatment, suggesting that it is a different entity from these enzymes. In the absence of an added oxidant, the enzyme preparation produced hydrogen gas under the atmosphere of carbon monoxide. The phenomenon can be explained assuming the reductive decomposition of water. 17 references, 4 figures, 2 tables.

  14. Picosecond absorption studies of photoinduced charge separation in polyelectrolyte bound aromatic chromophores

    Science.gov (United States)

    Shand, M. A.; Rodgers, M. A. J.; Webber, S. E.

    1991-02-01

    Picosecond absorption studies of photoinduced electron transfer between aromatic chromophores bound to polymethacrylic acid (P) and methylviologen (MV 2+ have been carried out in aqueous solution. The diphenylanthracene copolymer/viologen system at pH 2.8 shows the corresponding redox products DPA + rad and MV + rad arising from the singlet state of DPA with a forward rate constant of electron transfer of 2.6 × 10 9 s -1. At pH 9.0 the quenching of the S 1 state of DPA occurs with no charge separated products being observed. The pyrene copolymer shows no evidence of charge separated products at any pH in the range 2.8-9.0. It is proposed that the differences in the radical pair kinetics arise from differences in the degree of binding of the ground state complexes formed by the donor and acceptor species.

  15. Effect of exogenous electron shuttles on growth and fermentative metabolism in Clostridium sp. BC1

    Energy Technology Data Exchange (ETDEWEB)

    Yarlagadda V. N.; Francis A.; Gupta, A.; Dodge, C. J.

    2012-03-01

    In this study, the influence exogenous electron shuttles on the growth and glucose fermentative metabolism of Clostridium sp. BC1 was investigated. Bicarbonate addition to mineral salts (MS) medium accelerated growth and glucose fermentation which shifted acidogenesis (acetic- and butyric-acids) towards solventogenesis (ethanol and butanol). Addition of ferrihydrite, anthraquinone disulfonate, and nicotinamide adenine dinucleotide in bicarbonate to growing culture showed no significant influence on fermentative metabolism. In contrast, methyl viologen (MV) enhanced ethanol- and butanol-production by 28- and 12-fold, respectively with concomitant decrease in hydrogen, acetic- and butyric-acids compared to MS medium. The results show that MV addition affects hydrogenase activity with a significant reduction in hydrogen production and a shift in the direction of electron flow towards enhanced production of ethanol and butanol.

  16. Pulse-radiolytic one-electron reduction of anthraquinone and chloro-anthraquinones in aqueous-isopropanol-acetone mixed solvent

    International Nuclear Information System (INIS)

    Rath, M.C.; Pal, H.; Mukherjee, T.

    1996-01-01

    One-electron reduction of 9,10-anthraquinone and some chloro-anthraquinones and the characteristics of the semiquinones thus formed have been investigated in aqueous-isipropanol-acetone mixed solvent using electron pulse radiolysis technique. Spectroscopic characteristics, kinetic parameters of formation and decay, and the acid/base behaviour of the semiquinones have been investigated. The one-electron reduction potential of the quinones have been measured following electron transfer equilibria with a reference redox system (methyl viologen) and the values thus obtained have been compared with those of some other anthrasemiquinone systems. An analysis of the characteristics of the semiquinones shows that α-chloro substituents adjacent to the C=O group act as electron withdrawing groups. (author)

  17. Superoxide-responsive gene expression in Arabidopsis thaliana and Zea mays.

    Science.gov (United States)

    Xu, Junhuan; Tran, Thu; Padilla Marcia, Carmen S; Braun, David M; Goggin, Fiona L

    2017-08-01

    Superoxide (O 2 - ) and other reactive oxygen species (ROS) are generated in response to numerous biotic and abiotic stresses. Different ROS have been reported to elicit different transcriptional responses in plants, and so ROS-responsive marker genes and promoter::reporter gene fusions have been proposed as indirect means of detecting ROS and discriminating among different species. However, further information about the specificity of transcriptional responses to O 2 - is needed in order to assess potential markers for this critical stress-responsive signaling molecule. Using qRT-PCR, the expression of 12 genes previously reported to be upregulated by O 2 - was measured in Arabidopsis thaliana plants exposed to elicitors of common stress-responsive ROS: methyl viologen (an inducer of O 2 - ), rose bengal (an inducer of singlet oxygen, 1 ΔO 2 ), and exogenous hydrogen peroxide (H 2 O 2 ). Surprisingly, Zinc-Finger Protein 12 (AtZAT12), which had previously been used as a reporter for H 2 O 2 , responded more strongly to O 2 - than to H 2 O 2 ; moreover, the expression of an AtZAT12 promoter-reporter fusion (AtZAT12::Luc) was enhanced by diethyldithiocarbamate, which inhibits dismutation of O 2 - to H 2 O 2 . These results suggest that AtZAT12 is transcriptionally upregulated in response to O 2 - , and that AtZAT12::Luc may be a useful biosensor for detecting O 2 - generation in vivo. In addition, transcripts encoding uncoupling proteins (AtUCPs) showed selectivity for O 2 - in Arabidopsis, and an AtUCP homolog upregulated by methyl viologen was also identified in maize (Zea mays L.), indicating that there are O 2 - -responsive members of this family in monocots. These results expand our limited knowledge of ROS-responsive gene expression in monocots, as well as O 2 - -selective responses in dicots. Copyright © 2017 The Authors. Published by Elsevier Masson SAS.. All rights reserved.

  18. Electron transfer reactions induced by the triplet state of thiacarbocyanine dimers

    International Nuclear Information System (INIS)

    Chibisov, Alexander K.; Slavnova, Tatyana D.; Goerner, Helmut

    2004-01-01

    The photoinduced electron transfer between either cationic 5,5 ' -dichloro-3,3 ' ,9-triethylthiacarbocyanine (1) or a structurally similar anionic dye (2) and appropriate donors, e.g. ascorbic acid, and acceptors, e.g. methyl viologen, was studied by ns-laser photolysis. In aqueous solution the dyes in the ground state are present as an equilibrated mixture of dimers and monomers, whereas the triplet state is mainly populated from dimers. The triplet states of both dimers and monomers are quenched by electron donors or acceptors and the rate constant for quenching is generally 2-4 times higher for dimers than for monomers. The kinetics of triplet decay and radical formation and decay as a result of primary and secondary electron transfer were analyzed. While the one-electron reduced dimer decays due to back reactions, the one-electron oxidized dimer rapidly dissociates into the monomer and the monomeric dye radical. For the dimeric dye/donor/acceptor systems the primary photoinduced electron transfer occurs either from the donor or to the acceptor yielding the dimeric dye radicals. The one-electron reduced dimer can be efficiently oxidized by acceptors, e.g. the rate constant for reaction of the dimeric dye radical of 1 with methyl viologen (photoreductive pathway of sensitization) is 1.6x10 9 M -1 s -1 . The photooxidative pathway of sensitization is more complicated; after dissociation of the dimeric dye radical, the monomeric dye radical is reduced in a secondary electron transfer from ascorbic acid, e.g. with a rate constant of 1x10 9 M -1 s -1 for 2, yielding the monomer. On increasing the donor concentration the photooxidative pathway of sensitization is switched to a photoreductive one

  19. Reductive Dissolution of Goethite and Hematite by Reduced Flavins

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Zhi; Zachara, John M.; Wang, Zheming; Shi, Liang; Fredrickson, Jim K.

    2013-10-02

    The abiotic reductive dissolution of goethite and hematite by the reduced forms of flavin mononucleotide (FMNH2) and riboflavin (RBFH2), electron transfer mediators (ETM) secreted by the dissimilatory iron-reducing bacterium Shewanella, was investigated under stringent anaerobic conditions. In contrast to the rapid redox reaction rate observed for ferrihydrite and lepidocrocite (Shi et al., 2012), the reductive dissolution of crystalline goethite and hematite was slower, with the extent of reaction limited by the thermodynamic driving force at circumneutral pH. Both the initial reaction rate and reaction extent increased with decreasing pH. On a unit surface area basis, goethite was less reactive than hematite between pH 4.0 and 7.0. AH2DS, the reduced form of the well-studied synthetic ETM anthraquinone-2,6-disulfonate (AQDS), yielded higher rates than FMNH2 under most reaction conditions, despite the fact that FMNH2 was a more effective reductant than AH2DS for ferryhydrite and lepidocrocite. Two additional model compounds, methyl viologen and benzyl viologen, were investigated under similar reaction conditions to explore the relationship between reaction rate and thermodynamic properties. Relevant kinetic data from the literature were also included in the analysis to span a broad range of half-cell potentials. Other conditions being equal, the surface area normalized initial reaction rate (ra) increased as the redox potential of the reductant became more negative. A non-linear, parabolic relationship was observed between log ra and the redox potential for eight reducants at pH 7.0, as predicted by Marcus theory for electron transfer. When pH and reductant concentration were fixed, log ra was positively correlated to the redox potential of four Fe(III) oxides over a wide pH range, following a non-linear parabolic relationship as well.

  20. PHYSIOLOGICAL AND SANITARY QUALITY OF DESICCATED AND STORED AZUKI BEAN SEEDS

    Directory of Open Access Journals (Sweden)

    CÁSSIO JARDIM TAVARES

    2016-01-01

    Full Text Available The objective of this research was to evaluate the effects of using different herbicides as desiccants in pre - harvest and the effects of storage on the physiological and sanitary quality of azuki bean seeds ( Vigna angularis Willd. The experiment was arranged in a randomized complete block design in a split plot scheme, with four replications. Four herbicides were tested: paraquat (400 g a.i. ha - 1 , glufosinate ammonium (400 g a.i. ha - 1 , glyphosate (720 g a.i. ha - 1 , flumioxazin (30 g a.i. ha - 1 and a control without herbicide application. In the subplots seed quality was tested in two evaluation periods: at harvest and six months after harvest. Desiccant was applied when the azuki beans were physiologically mature. We assessed the physiological and sanitary quality of the seeds using a vigour and seed health test. The use of glyphosate resulted in a higher incidence of abnormal seedlings and reduced size and weight of the seedlings. With paraquat and flumioxazin the physiological quality was maintained and there was reduced pathogen infestation in the seeds six months after harvest. Storage affected the physiological quality of the azuki bean seeds.

  1. Palmistichus elaeisis (Hymenoptera: Eulophidae as an indicator of toxicity of herbicides registered for corn in Brazil

    Directory of Open Access Journals (Sweden)

    Claubert W.G de Menezes

    2014-09-01

    Full Text Available The diversity of plants in agricultural systems benefits natural enemies. Herbicides are used in weed management in corn (Zea mays L. to reduce competition and productivity losses, but they can impact natural enemies and contaminate the environment. The objective was to evaluate toxicity of herbicides on pupae parasitoid Palmistichus elaeisis Delvare and LaSalle, 1993 (Hymenoptera: Eulophidae. The treatments were represented by the host pupae Tenebrio molitor L., 1785 (Coleoptera: Tenebrionidae and herbicides atrazine, nicosulfuron, paraquat, and tembotrione in commercial doses compared to a control treatment with water. Pupae of T. molitor were immersed in the solution of herbicides and exposed to parasitism by six females of P. elaeisis each. The herbicides atrazine and paraquat were highly toxic and, therefore, not selective to P. elaeisis. Nicosulfuron reduced the sex ratio of P. elaeisis (0.20 ± 0.03, which may affect subsequent generations. Moreover, the herbicide tembotrione was selective to P. elaeisis, showing results comparable to the control. Floristic diversity of weeds can increase food source, habitat, shelter, breeding places and microclimates for insect parasitoids but herbicides formulations can be toxic and these products can affect P. elaeisis or its hosts by direct or indirect contact, showing the importance of selectivity studies for this natural enemy. However, the herbicide tembotrione was selective to P. elaeisis and it can be recommended for programs of sustainable management of weeds in corn crop with this parasitoid.

  2. One-step preparation of nanostructured martite catalyst and graphite electrode by glow discharge plasma for heterogeneous electro-Fenton like process.

    Science.gov (United States)

    Khataee, Alireza; Sajjadi, Saeed; Hasanzadeh, Aliyeh; Vahid, Behrouz; Joo, Sang Woo

    2017-09-01

    Natural Martite ore particles and graphite were modified by alternating current (AC) glow discharge plasma to form nanostructured catalyst and cathode electrode for using in the heterogeneous-electro Fenton-like (Het-EF-like) process. The performance of the plasma-treated martite (PTM) and graphite electrode (PTGE) was studied for the treatment of paraquat herbicide in a batch system. 85.78% degradation efficiency for 20 mg L -1 paraquat was achieved in the modified process under desired operational conditions (i.e. current intensity of 300 mA, catalyst amount of 1 g L -1 , pH = 6, and background electrolyte (Na 2 SO 4 ) concentration of 0.05 mol L -1 ) which was higher than the 41.03% for the unmodified one after 150 min of treatment. The ecofriendly modification of the martite particles and the graphite electrode, no chemical needed, low leached iron and milder operational pH were the main privileges of plasma utilization. Moreover, the degradation efficiency through the process was not declined after five repeated cycles at the optimized conditions, which proved the stability of the nanostructured PTM and PTGE in the long-term usage. The archived results exhibit this method is the first example of high efficient, cost-effective, and environment-friendly method for generation of nanostructured samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. The Mitochondrial Lon Protease Is Required for Age-Specific and Sex-Specific Adaptation to Oxidative Stress.

    Science.gov (United States)

    Pomatto, Laura C D; Carney, Caroline; Shen, Brenda; Wong, Sarah; Halaszynski, Kelly; Salomon, Matthew P; Davies, Kelvin J A; Tower, John

    2017-01-09

    Multiple human diseases involving chronic oxidative stress show a significant sex bias, including neurodegenerative diseases, cancer, immune dysfunction, diabetes, and cardiovascular disease. However, a possible molecular mechanism for the sex bias in physiological adaptation to oxidative stress remains unclear. Here, we report that Drosophila melanogaster females but not males adapt to hydrogen peroxide stress, whereas males but not females adapt to paraquat (superoxide) stress. Stress adaptation in each sex requires the conserved mitochondrial Lon protease and is associated with sex-specific expression of Lon protein isoforms and proteolytic activity. Adaptation to oxidative stress is lost with age in both sexes. Transgenic expression of transformer gene during development transforms chromosomal males into pseudo-females and confers the female-specific pattern of Lon isoform expression, Lon proteolytic activity induction, and H 2 O 2 stress adaptation; these effects were also observed using adult-specific transformation. Conversely, knockdown of transformer in chromosomal females eliminates the female-specific Lon isoform expression, Lon proteolytic activity induction, and H 2 O 2 stress adaptation and produces the male-specific paraquat (superoxide) stress adaptation. Sex-specific expression of alternative Lon isoforms was also observed in mouse tissues. The results develop Drosophila melanogaster as a model for sex-specific stress adaptation regulated by the Lon protease, with potential implications for understanding sexual dimorphism in human disease. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Metabonomic strategy for the investigation of the mode of action of the phytotoxin (5S,8R,13S,16R)-(-)-pyrenophorol using 1H nuclear magnetic resonance fingerprinting.

    Science.gov (United States)

    Aliferis, Konstantinos A; Chrysayi-Tokousbalides, Maria

    2006-03-08

    The biochemical mode of action of (5S,8R,13S,16R)-(-)-pyrenophorol isolated from a Drechslera avenae pathotype was investigated by using metabolic fingerprinting. (1)H NMR spectra of crude leaf extracts from untreated Avena sterilis seedlings and A. sterilis seedlings treated with pyrenophorol were compared with those obtained from treatments with the herbicides diuron, glyphosate, mesotrione, norflurazon, oxadiazon, and paraquat. Multivariate analysis was carried out to group treatments according to the mode of action of the phytotoxic substances applied. Analysis results revealed that none of the herbicide treatments fitted the pyrenophorol model and indicate that the effect of the phytotoxin on A. sterilis differs than those caused by glyphosate, mesotrione, norflurazon, oxadiazon, paraquat, and diuron, which inhibit 5-enolpyruvylshikimate-3-phosphate synthase, 4-hydroxyphenyl-pyruvate-dioxygenase, phytoene desaturase, protoporphyrinogen oxidase, photosystem I, and photosystem II, respectively. The method applied, combined with appropriate data preprocessing and analysis, was found to be rapid for the screening of phytotoxic substances for metabolic effects.

  5. Linkages between the life-history evolution of tropical and temperate birds and the resistance of cultured skin fibroblasts to oxidative and non-oxidative chemical injury.

    Science.gov (United States)

    Jimenez, Ana Gabriela; Harper, James M; Queenborough, Simon A; Williams, Joseph B

    2013-04-15

    A fundamental challenge facing physiological ecologists is to understand how variation in life history at the whole-organism level might be linked to cellular function. Thus, because tropical birds have higher annual survival and lower rates of metabolism, we hypothesized that cells from tropical species would have greater cellular resistance to chemical injury than cells from temperate species. We cultured dermal fibroblasts from 26 tropical and 26 temperate species of birds and examined cellular resistance to cadmium, H(2)O(2), paraquat, thapsigargin, tunicamycium, methane methylsulfonate (MMS) and UV light. Using ANCOVA, we found that the values for the dose that killed 50% of cells (LD(50)) from tropical birds were significantly higher for H(2)O(2) and MMS. When we tested for significance using a generalized least squares approach accounting for phylogenetic relationships among species to model LD(50), we found that cells from tropical birds had greater tolerance for Cd, H(2)O(2), paraquat, tunicamycin and MMS than cells from temperate birds. In contrast, tropical birds showed either lower or no difference in tolerance to thapsigargin and UV light in comparison with temperate birds. These findings are consistent with the idea that natural selection has uniquely fashioned cells of long-lived tropical bird species to be more resistant to forms of oxidative and non-oxidative stress than cells from shorter-lived temperate species.

  6. Bioactive Peptides from Angelica sinensis Protein Hydrolyzate Delay Senescence in Caenorhabditis elegans through Antioxidant Activities

    Directory of Open Access Journals (Sweden)

    Qiangqiang Wang

    2016-01-01

    Full Text Available Since excessive reactive oxygen species (ROS is known to be associated with aging and age-related diseases, strategies modulating ROS level and antioxidant defense systems may contribute to the delay of senescence. Here we show that the protein hydrolyzate from Angelica sinensis was capable of increasing oxidative survival of the model animal Caenorhabditis elegans intoxicated by paraquat. The hydrolyzate was then fractionated by ultrafiltration, and the antioxidant fraction (<3 kDa was purified by gel filtration to obtain the antioxidant A. sinensis peptides (AsiPeps, which were mostly composed of peptides with <20 amino acid residues. Further studies demonstrate that AsiPeps were able to reduce the endogenous ROS level, increase the activities of the antioxidant enzymes superoxide dismutase and catalase, and decrease the content of the lipid peroxidation product malondialdehyde in nematodes treated with paraquat or undergoing senescence. AsiPeps were also shown to reduce age pigments accumulation and extend lifespan but did not affect the food-intake behavior of the nematodes. Taken together, our results demonstrate that A. sinensis peptides (AsiPeps are able to delay aging process in C. elegans through antioxidant activities independent of dietary restriction.

  7. Avaliação de diferentes herbicidas para erradicação química de coqueiros infectados com resinose Herbicide selection for chemical eradication of coconut palms infected with stem-bleeding

    Directory of Open Access Journals (Sweden)

    H.R. Fontes

    2009-01-01

    Full Text Available Objetivou-se neste trabalho selecionar herbicidas que possam ser utilizados na erradicação química de coqueiros infectados com resinose. O experimento foi instalado no município de Neópolis - SE, no período de junho a julho de 2007. Utilizou-se uma população de coqueiros da variedade anão-verde, implantada há 11 anos. O delineamento experimental foi o inteiramente casualizado, em parcelas subdivididas no tempo, com cinco repetições (cada unidade experimental foi composta por um coqueiro infectado. Os tratamentos foram formados pela combinação de dez tratamentos herbicidas {MSMA (36 g por planta; glyphosate (18 g por planta; paraquat (10 g por planta; [2,4-D + picloram] (18 + 1,125 g por planta; [2,4-D + picloram] + paraquat ([9 + 0,5625] + 5 g por planta; MSMA + glyphosate (18 + 9 g por planta; MSMA + paraquat (18 + 5 g por planta; glyphosate + paraquat (9 + 5 g por planta; [2,4-D + picloram] + MSMA ([9 + 0,5625] + 18 g por planta; tratamento controle (testemunha sem aplicação} e de quatro épocas de avaliação (7, 14, 21 e 28 dias após a aplicação dos tratamentos herbicidas. Os herbicidas foram injetados no estipe dos coqueiros em um furo de 25 cm de profundidade, 5 cm de diâmetro e inclinação de 45º, localizado a 1,0 m de altura. A aplicação foi realizada por intermédio de uma seringa graduada, imediatamente após a abertura dos furos, sendo os herbicidas aplicados sem diluição. Foram realizadas quatro avaliações da dessecação dos coqueiros, aos 7, 14, 21 e 28 dias após a aplicação dos tratamentos (DAA. O herbicida MSMA foi o que resultou na dessecação mais rápida dos coqueiros doentes, além de promover a morte de todas as plantas avaliadas, sendo por isso o tratamento mais indicado na continuação dos estudos visando à proposição de uma técnica para a erradicação química de coqueiros infectados com resinose.The objective of this work was to select herbicides that can be used to chemically

  8. Resistance of Lactobacillus plantarum KCTC 3099 from Kimchi to oxidative stress.

    Science.gov (United States)

    Lee, Jeongmin; Hwang, Kwon-Tack; Heo, Moon-Soo; Lee, Jun-Haeng; Park, Kun-Young

    2005-01-01

    The antioxidative capacity of two lactic acid bacteria isolated from Kimchi, a Korean fermented food, was evaluated by measuring the resistance to reactive oxygen species (ROS) and compared with that of Lactobacillus rhamnosus GG as a positive control. Both intact cells and cell-free extracts of Lactobacillus plantarum KCTC 3099 exhibited higher antioxidative activity in inhibiting lipid peroxidation among the strains evaluated with an inhibitory level of 38.6% and 48.5%, respectively. To evaluate the resistance of the two lactic acid bacteria to ROS, we tested their survival in the presence of 1 mM hydrogen peroxide, 0.4 mM hydroxyl radicals, and superoxide anions induced by 10 mM paraquat. L. plantarum KCTC 3099 was viable even after 8 hours in the presence of both 1 mM hydrogen peroxide and 0.4 mM hydroxyl radicals. Moreover, the survival of L. plantarum KCTC 3099 was not affected by superoxide anions generated by using paraquat, indicating that it has resistance to superoxide anions. To define the antioxidative mechanism, superoxide dismutase (SOD) and metal ion chelating activities were determined. L. plantarum KCTC 3099 presented little SOD activity, but had the higher level of chelating activity for both Fe2+ and Cu2+ metal ions at 13.6 ppm and 23.9 ppm, respectively. These results suggested that the antioxidative capacity of L. plantarum KCTC 3099 is apparently caused by chelating metal ions rather than by SOD activation.

  9. Aplicação simultânea de dessecantes e boro no manejo de plantas daninhas e na nutrição mineral das culturas de soja e girassol Simultaneous application of desiccants and boron for weed control and mineral nutrition of soybean and sunflower

    Directory of Open Access Journals (Sweden)

    A.M. Brighenti

    2006-12-01

    Full Text Available Dois experimentos foram conduzidos com o objetivo de avaliar o controle de plantas daninhas em pré-semeadura da soja (Glycine max e do girassol (Helianthus annuus, por meio de aplicações de herbicidas dessecantes, isolados ou em combinação com boro, bem como a resposta dessas culturas à aplicação desse micronutriente. Nas parcelas de soja, foram aplicados os tratamentos glyphosate (1,44 kg e.a. ha-1, glyphosate potássico (2,48 kg i.a. ha-1, diuron (0,2 kg i.a. ha-1 + paraquat (0,4 kg i.a. ha-1, e paraquat (0,400 kg i.a. ha-1. Nas parcelas de girassol, foram aplicados os tratamentos glyphosate (0,54 kg e.a. ha-1, glyphosate (0,72 kg e.a. ha-1, glyphosate potássico (1,24 kg i.a. ha-1, paraquat (0,4 kg i.a. ha-1, glyphosate (0,72 kg e.a. ha-1 + flumioxazin (0,025 kg i.a. ha-1 e glyphosate (0,72 kg e.a. ha-1 + carfentrazone (0,02 kg i.a. ha-1. Ambos os experimentos continham as testemunhas capinada e sem capina. As subparcelas dos dois experimentos foram constituídas pela ausência ou presença de B, junto à calda de pulverização, na fonte ácido bórico [H3BO3 - 17% B]. A adição de ácido bórico à calda de pulverização não prejudicou o controle das plantas daninhas pelos tratamentos dessecantes, exceto para a mistura formulada de paraquat + diuron. Houve aumento dos teores de boro no solo e nas folhas da cultura da soja e do girassol quando foram associados os tratamentos com herbicidas dessecantes e o ácido bórico. É viável a aplicação de herbicidas dessecantes e ácido bórico, controlando as plantas daninhas em présemeadura e aumentando o teor de B no solo e nas plantas de soja e de girassol.Two experiments were carried out to evaluate weed control in soybean (Glycine max and sunflower (Helianthus annuus pre-sowing by desiccant application alone or in combination with boron (B, as well as to evaluate the response of these crops to that micronutrient. The plots consisted of the desiccants glyphosate (1.44 kg a.e. ha-1

  10. Reactions of tobacco genotypes with different antioxidant capacities to powdery mildew and Tobacco mosaic virus infections.

    Science.gov (United States)

    Gullner, Gábor; Juhász, Csilla; Németh, Adél; Barna, Balázs

    2017-10-01

    The interactions of powdery mildew (Golovinomyces orontii) and Tobacco mosaic virus (TMV) with tobacco lines having down or upregulated antioxidants were investigated. Xanthi-nc, its salicylic acid-deficient NahG mutant, a paraquat-sensitive Samsun (PS) and its paraquat tolerant (PT) mutant were used. Cell membrane damage caused by H 2 O 2 was significantly higher in NahG than Xanthi, whereas it was lower in PT than in PS. Leakage of ions from PT was reduced by the powdery mildew infection. On the other hand TMV inoculation led to a 6-fold and 2-fold elevation of ion leakage from hypersensitive resistant NahG and Xanthi leaves, respectively, whereas ion leakage increased slightly from susceptible PS leaves. G. orontii infection induced ribonuclease (RNase) enzyme activity in extracts from Xanthi and NahG (about 200-250% increase) and weakly (about 20-30% increase) from PS and PT lines. Pre-treatment with protein kinase inhibitor staurosporine or protein phosphatase inhibitor okadaic acid very strongly inhibited mildew development on tobacco lines. Our experiments suggest that protein kinases inhibited by staurosporine seem to be important factors, while protein phosphatases inhibited by okadaic acid play less significant role in TMV-induced lesion development. Both powdery mildew and TMV infections up-regulated the expression of PR-1b, PR-1c and WRKY12 genes in all tobacco lines to various extents. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  11. Effects of biocides on chlorophyll contents of detached basil leaves

    Directory of Open Access Journals (Sweden)

    Titima Arunrangsi

    2013-06-01

    Full Text Available Herbicides and insecticides have been widely and intensively used in agricultural areas worldwide to enhance crop yield. However, many biocides cause serious environmental problems. In addition, the biocides may also have some effects on the treated agricultural crops. To study effects of biocides on chlorophyll content in detached basil leaves, 2,4-D dimethylamine salt (2,4 D-Amine, paraquat, carbosulfan, and azadirachtin, were chosen as representatives of biocide. After applying the chemicals to detached basil leaves overnight in darkness, chlorophyll contents were determined. Only treatment with 2,4 D-Amine resulted in reduction of chlorophyll contents significantly compared to treatment with deionized (DI water. In the case of paraquat and carbosulfan, chlorophyll contents were not significantly changed, while slightly higher chlorophyll contents, compared to DI water, after the treatment with azadirachtin, were observed. The results indicated that 2,4 D-Amine shows an ability to accelerate chlorophyll degradation, but azadirachtin helps to retard chlorophyll degradation, when each biocide is used at the concentration recommended by the manufacturer.

  12. Biological Research for Radiation Protection

    International Nuclear Information System (INIS)

    Kim, In Gyu; Kim, Kug Chan; Jung, Il Lae; Choi, Yong Ho; Kim, Jin Sik; Moon, Myung Sook; Byun, Hee Sun; Phyo, Ki Heon; Kim, Sung Keun

    2005-04-01

    The work scope of 'Biological Research for the Radiation Protection' had contained the research about ornithine decarboxylase and its controlling proteins, thioredoxin, peroxiredoxin, S-adenosymethionine decarboxylase, and glutamate decarboxylase 67KD effect on the cell death triggered ionizing radiation and H 2 O 2 (toxic agents). In this study, to elucidate the role of these proteins in the ionizing radiation (or H 2 O 2 )-induced apoptotic cell death, we utilized sensesed (or antisensed) cells, which overexpress (or down-regulate) RNAs associated with these proteins biosynthesis, and investigated the effects of these genes on the cytotoxicity caused by ionizing radiation and H 2 O 2 (or paraquat). We also investigated whether genisteine(or thiamine) may enhance the cytotoxic efficacy of tumor cells caused by ionizing radiation (may enhance the preventing effect radiation or paraquat-induced damage) because such compounds are able to potentiate the cell-killing or cell protecting effects. Based on the above result, we suggest that the express regulation of theses genes have potentially importance for sensitizing the efficiency of radiation therapy of cancer or for protecting the radiation-induced damage of normal cells

  13. Environmental Exposures and Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Sirisha Nandipati

    2016-09-01

    Full Text Available Parkinson’s disease (PD affects millions around the world. The Braak hypothesis proposes that in PD a pathologic agent may penetrate the nervous system via the olfactory bulb, gut, or both and spreads throughout the nervous system. The agent is unknown, but several environmental exposures have been associated with PD. Here, we summarize and examine the evidence for such environmental exposures. We completed a comprehensive review of human epidemiologic studies of pesticides, selected industrial compounds, and metals and their association with PD in PubMed and Google Scholar until April 2016. Most studies show that rotenone and paraquat are linked to increased PD risk and PD-like neuropathology. Organochlorines have also been linked to PD in human and laboratory studies. Organophosphates and pyrethroids have limited but suggestive human and animal data linked to PD. Iron has been found to be elevated in PD brain tissue but the pathophysiological link is unclear. PD due to manganese has not been demonstrated, though a parkinsonian syndrome associated with manganese is well-documented. Overall, the evidence linking paraquat, rotenone, and organochlorines with PD appears strong; however, organophosphates, pyrethroids, and polychlorinated biphenyls require further study. The studies related to metals do not support an association with PD.

  14. Physicochemical Characterization and Functional Analysis of the Polysaccharide from the Edible Microalga Nostoc sphaeroides

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    Haifeng Li

    2018-02-01

    Full Text Available Nostoc colonies have been used as food and medicine for centuries, and their main supporting matrix is polysaccharides, which help Nostoc cells resist various environmental stresses including oxidative stress. Here we isolated a polysaccharide, nostoglycan, from cultured Nostoc sphaeroides colonies and determined its physicochemical properties, which revealed a characteristic infrared absorption spectrum typical of polysaccharides and an amorphous morphology with rough surfaces. We also show that nostoglycan has strong moisture absorption and retention capacities and a high relative viscosity. Using Caenorhabditis elegans models, we then demonstrate that nostoglycan is capable of improving overall survival rate of the animals under increased oxidative stress caused by paraquat. Nostoglycan also reduces reactive oxygen species level, inhibits protein carbonyl formation and lipid peroxidation, and increases activities of superoxide dismutase and catalase in paraquat-exposed nematodes. As oxidative stress may drive tumor progression, we further demonstrate that nostoglycan can suppress the proliferation of several types of tumor cells and induce apoptosis of human lung adenocarcinoma A549 cells via caspase-3 activation. Together, our results yield important information on the physicochemical characteristics and demonstrate the antioxidant and anti-proliferative functions of nostoglycan, and thus provide an insight into its potential in food and health industries.

  15. Biomass chemicals: improvement in quality and quantity with physiological regulators

    Energy Technology Data Exchange (ETDEWEB)

    Kossuth, S.V.

    1984-01-01

    The search for alternative biomass energy forms has centered on two approaches: (1) production of cellulose fiber in biomass of low net energy value per unit weight, such as wood and bagasse, and (2) hydrocarbons of high net energy value per unit weight for use as chemical feedstocks and substitutes for petroleum. Major plant chemical products include oleoresin from pine (Pinus elliottii Engelm., P. palustris Mill.) rubber from the rubber tree (Hevea brasiliensis Muell.), and guayule shrub (Parthenium argentatum Gray) and sugar from sugarcane (Saccharum species). Ethylene may be a unifying natural bioregulator that can increase deposition of biomass chemicals in all four of these systems. Examples of bioregulators include the use of paraquat, diquat, and 2-chloroethylphosphonic acid (CEPA) for stimulating the synthesis of oleoresin, CEPA for prolonging the flow of rubber and increasing rubber synthesis in the rubber tree, and triethylamines of chlorinated phenoxy compounds for stimulating rubber production in guayule. In sugarcane, gibberellic acid (GA3) increases internodal elongation. Glyphosate, CEPA and other regulators increase the deposition of sucrose, diquat and CEPA inhibit flowering, and paraquat desiccates leaves to facilitate leaf removal or burning just prior to harvest. The cellular compartmentalization for the synthesis of these plant chemicals is unique for each species, and dictates cultural and harvest techniques. The mode of action and pathways for the success of these physiological regulators are discussed. 42 references.

  16. Fast analysis of quaternary ammonium pesticides in food and beverages using cation-exchange chromatography coupled with isotope-dilution high-resolution mass spectrometry.

    Science.gov (United States)

    Nardin, Tiziana; Barnaba, Chiara; Abballe, Franco; Trenti, Gianmaria; Malacarne, Mario; Larcher, Roberto

    2017-10-01

    A fast separation based on cation-exchange liquid chromatography coupled with high-resolution mass spectrometry is proposed for simultaneous determination of chlormequat, difenzoquat, diquat, mepiquat and paraquat in several food and beverage commodities. Solid samples were extracted using a mixture of water/methanol/formic acid (69.6:30:0.4, v/v/v), while liquid samples were ten times diluted with the same solution. Separation was carried out on an experimental length-modified IonPac CS17 column (2 × 15 mm 2 ) that allowed the use of formic acid and acetonitrile as mobile phase. Detection limits for food and beverage matrices were established at 1.5 μg/L for chlormequat, difenzoquat and mepiquat, and 3 μg/L for diquat and paraquat, while for drinking water a pre-analytical sample concentration allowed detection limits of 9 and 20 ng/L, respectively. Precision, as repeatability (RSD%), ranged from 0.2 to 24%, with a median value of 6%, and trueness, as recovery, ranged from 64 to 118%, with a median value of 96%. The method developed was successfully applied to investigate the presence of herbicide residues in commercial commodities (mineral water, orange juice, beer, tea, green coffee bean, toasted coffee powder, cocoa bean, white corn flour, rice and sugar samples). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. AFLP marker linked to water-stress-tolerant bulks in barley (Hordeum vulgare L.

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    A. Altinkut

    2003-01-01

    Full Text Available The amplified fragment length polymorphism (AFLP assay is an efficient method for the identification of molecular markers, useful in the improvement of numerous crop species. Bulked Segregant Analysis (BSA was used to identify AFLP markers associated with water-stress tolerance in barley, as this would permit rapid selection of water-stress tolerant genotypes in breeding programs. AFLP markers linked to water-stress tolerance was identified in two DNA pools (tolerant and sensitive, which were established using selected F2 individuals resulting from a cross between water-stress-tolerant and sensitive barley parental genotypes, based on their paraquat (PQ tolerance, leaf size, and relative water content (RWC. All these three traits were previously shown to be associated with water-stress tolerance in segregating F2 progeny of the barley cross used in a previous study. AFLP analysis was then performed on these DNA pools, using 40 primer pairs to detect AFLP fragments that are present/absent, respectively, in the two pools and their parental lines. One separate AFLP fragment, which was present in the tolerant parent and in the tolerant bulk, but absent in the sensitive parent and in the sensitive bulk, was identified. Polymorphism of the AFLP marker was tested among tolerant and sensitive F2 individuals. The presence of this marker that is associated with water-stress tolerance will greatly enhance selection for paraquat and water-stress tolerant genotypes in future breeding programs.

  18. Toxicity of herbicides used in the sugarcane crop to diazotrophic bacterium Herbaspirillum seropedicae

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    Sergio de Oliveira Procópio

    2014-10-01

    Full Text Available The objective of this work was to identify herbicides used in the sugarcane crop that affects neither the growth, the development, of nor the process of biological nitrogen fixation (BNF by the diazotrophic bacterium Herbaspirillum seropedicae. Eighteen herbicides (paraquat, ametryne, tebuthiuron, amicarbazone, diuron, metribuzin, [hexazinone + diuron], [hexazinone + clomazone], clomazone, isoxaflutole, sulfentrazone, oxyfluorfen, imazapic, imazapyr, [trifloxysulfuron sodium + ametryne], glyphosate, MSMA e 2,4-D were tested in their respective commercial doses regarding their impact on the growth of the bacteria in liquid medium DIGs. For this, we determined the duration of lag phase, generation time and maximum cell density of H. seropedicae, calculated from optical density data obtained at regular intervals during the incubation of cultures for 33 h at 32oC. We also evaluated the impact of herbicides on nitrogenase activity of H. seropedicae grown in semi-solid N-free JNFb medium. The effects of herbicides on the growth variables and the ARA were compared with the untreated control by Dunnett test. A completely randomized design was used. The herbicides paraquat, imazapyr, ametryne, glyphosate and oxyfluorfen inhibited the growth of H. seropedicae in vitro. Ametryne, oxyfluorfen and glyphosate caused a small reduction in the duration of the lag phase of diazotrophic bacteria H. seropedicae. Oxyfluorfen, ametryne and imazapyr resulted in increased the generation time by H. seropedicae. Glyphosate promoted drastic reduction in biological nitrogen fixation in vitro by H. seropedicae. The other tested herbicides did not affect the growth or the same BNF by H. seropedicae.

  19. The generation of singlet oxygen (o(2)) by the nitrodiphenyl ether herbicide oxyfluorfen is independent of photosynthesis.

    Science.gov (United States)

    Haworth, P; Hess, F D

    1988-03-01

    The mechanism of action of the p-nitrodiphenyl ether herbicides has remained ambiguous because of conflicting reports in the literature. The diphenyl ether herbicide oxyfluorfen causes a light induced consumption of oxygen which resembles the electron acceptor reaction of paraquat. However, this reaction is not linked to the transport of electrons through photosystem I. This conclusion is based on the observation that the rate of oxygen consumption, in the presence of oxyfluorfen, does not demonstrate a first order rate dependence on light intensity. Using the bleaching of N,N-dimethyl p-nitrosoaniline as a specific detector of singlet oxygen, we demonstrate that oxyfluorfen is a potent generator of this toxic radical. The production of singlet oxygen occurs in the presence of inhibitors of photosynthetic electron transport (oxyfluorfen at 10(-4) molar and paraquat) and also under temperature conditions (3 degrees C) which prevent electron transport. This light induced reaction results in oxygen consumption and is the primary cause of lethality for oxyfluorfen. The production of singlet oxygen occurs rapidly and at low herbicide concentrations (10(-9) molar). The reaction occurs without photosynthetic electron transport but does require an intact thylakoid membrane.

  20. The Generation of Singlet Oxygen (1O2) by the Nitrodiphenyl Ether Herbicide Oxyfluorfen Is Independent of Photosynthesis

    Science.gov (United States)

    Haworth, Phil; Hess, F. Dan

    1988-01-01

    The mechanism of action of the p-nitrodiphenyl ether herbicides has remained ambiguous because of conflicting reports in the literature. The diphenyl ether herbicide oxyfluorfen causes a light induced consumption of oxygen which resembles the electron acceptor reaction of paraquat. However, this reaction is not linked to the transport of electrons through photosystem I. This conclusion is based on the observation that the rate of oxygen consumption, in the presence of oxyfluorfen, does not demonstrate a first order rate dependence on light intensity. Using the bleaching of N,N-dimethyl p-nitrosoaniline as a specific detector of singlet oxygen, we demonstrate that oxyfluorfen is a potent generator of this toxic radical. The production of singlet oxygen occurs in the presence of inhibitors of photosynthetic electron transport (oxyfluorfen at 10−4 molar and paraquat) and also under temperature conditions (3°C) which prevent electron transport. This light induced reaction results in oxygen consumption and is the primary cause of lethality for oxyfluorfen. The production of singlet oxygen occurs rapidly and at low herbicide concentrations (10−9 molar). The reaction occurs without photosynthetic electron transport but does require an intact thylakoid membrane. PMID:16665968

  1. Isolation and characterization of a metallothionein-1 protein in Chloris virgata Swartz that enhances stress tolerances to oxidative, salinity and carbonate stress in Saccharomyces cerevisiae.

    Science.gov (United States)

    Nishiuchi, Shunsaku; Liu, Shenkui; Takano, Tetsuo

    2007-08-01

    Chloris virgata Swartz (C. virgata) is a gramineous wild plant that is found in alkaline soil areas in northeast China and is highly tolerant to carbonate stress. We constructed a cDNA library from C. virgata seedlings treated with NaHCO(3), and isolated a type 1 metallothionein (MT1) gene (ChlMT1: AB294238) from the library. The amino acid sequence of ChlMT1 contained 12 cysteine residues that constituted the Cys-X-Cys (X = amino acid except Cys) motifs in the N- and C-terminal regions. Northern hybridization showed that expression of ChlMT1 was induced by several abiotic stresses, from salts (NaCl and NaHCO(3)), a ROS inducer (paraquat), and metals (CuSO(4), ZnSO(4), and CoCl(2)). ChlMT1 expression in leaf was induced by 200 mM NaCl and 100 mM NaHCO(3). About 5 microM Paraquat, 500 microM Zn(2+), and 500 microM Co(2+) also induced expression of ChlMT1 in leaf after 6 h, and 100 microM Cu(2+) induced it after 24 h. Saccharomyces cerevisiae when transformed with the ChlMT1 gene had dramatically increased tolerances to salts (NaCl and NaHCO(3)) and ROS.

  2. Formation of non-extractable pesticide residues: observations on compound differences, measurement and regulatory issues

    Energy Technology Data Exchange (ETDEWEB)

    Mordaunt, Catriona J.; Gevao, Bondi; Jones, Kevin C.; Semple, Kirk T

    2005-01-01

    Six major use pesticides (Atrazine, Dicamba, Isoproturon, Lindane, Paraquat and Trifluralin) with differing physico-chemical properties were evaluated for the significance of 'bound' or non extractable residue formation. Investigations were carried out in purpose-built microcosms where mineralization, volatilisation, 'soil water' extractable and organic solvent extractable residues could be quantified. Extractable residues were defined as those accessible by sequential extraction where the solvent used became increasingly non-polar. Dichloromethane was the 'harshest' solvent used at the end of the sequential extraction procedure. {sup 14}C-labelled volatilised and {sup 14}CO{sub 2} fractions were trapped on exit from the microcosm. The pesticides were categorised into 3 classes based on their behaviour. (i) Type A (Atrazine, Lindane and Trifluralin) in which ring degradation was limited as was the formation of non-extractable residues; the remainder of the {sup 14}C-activity was found in the extractable fraction. (ii) Type B (Dicamba and Isoproturon) in which approximately 25% of the {sup 14}C-activity was mineralised and a large portion was found in the non-extractable fraction after 91 days. Finally, Type C (Paraquat) in which almost all of the {sup 14}C-activity was quickly incorporated into the non-extractable fraction. The implications of the data are discussed, with respect to the variability and significance of regulatory aspects of non-extractable residues.

  3. Formation of non-extractable pesticide residues: observations on compound differences, measurement and regulatory issues

    International Nuclear Information System (INIS)

    Mordaunt, Catriona J.; Gevao, Bondi; Jones, Kevin C.; Semple, Kirk T.

    2005-01-01

    Six major use pesticides (Atrazine, Dicamba, Isoproturon, Lindane, Paraquat and Trifluralin) with differing physico-chemical properties were evaluated for the significance of 'bound' or non extractable residue formation. Investigations were carried out in purpose-built microcosms where mineralization, volatilisation, 'soil water' extractable and organic solvent extractable residues could be quantified. Extractable residues were defined as those accessible by sequential extraction where the solvent used became increasingly non-polar. Dichloromethane was the 'harshest' solvent used at the end of the sequential extraction procedure. 14 C-labelled volatilised and 14 CO 2 fractions were trapped on exit from the microcosm. The pesticides were categorised into 3 classes based on their behaviour. (i) Type A (Atrazine, Lindane and Trifluralin) in which ring degradation was limited as was the formation of non-extractable residues; the remainder of the 14 C-activity was found in the extractable fraction. (ii) Type B (Dicamba and Isoproturon) in which approximately 25% of the 14 C-activity was mineralised and a large portion was found in the non-extractable fraction after 91 days. Finally, Type C (Paraquat) in which almost all of the 14 C-activity was quickly incorporated into the non-extractable fraction. The implications of the data are discussed, with respect to the variability and significance of regulatory aspects of non-extractable residues

  4. Prandiology of Drosophila and the CAFE assay

    Science.gov (United States)

    Ja, William W.; Carvalho, Gil B.; Mak, Elizabeth M.; de la Rosa, Noelle N.; Fang, Annie Y.; Liong, Jonathan C.; Brummel, Ted; Benzer, Seymour

    2007-01-01

    Studies of feeding behavior in genetically tractable invertebrate model systems have been limited by the lack of proper methodology. We introduce the Capillary Feeder (CAFE), a method allowing precise, real-time measurement of ingestion by individual or grouped fruit flies on the scale of minutes to days. Using this technique, we conducted the first quantitative analysis of prandial behavior in Drosophila melanogaster. Our results allow the dissection of feeding into discrete bouts of ingestion, defining two separate parameters, meal volume and frequency, that can be uncoupled and thus are likely to be independently regulated. In addition, our long-term measurements show that flies can ingest as much as 1.7× their body mass over 24 h. Besides the study of appetite, the CAFE can be used to monitor oral drug delivery. As an illustration, we used the CAFE to test the effects of dietary supplementation with two compounds, paraquat and ethanol, on food ingestion and preference. Paraquat, a prooxidant widely used in stress tests, had a strong anorexigenic effect. In contrast, in a feeding preference assay, ethanol-laced food, but not ethanol by itself, acted as an attractant. PMID:17494737

  5. Oxidative Stressors Modify the Response of Streptococcus mutans to Its Competence Signal Peptides.

    Science.gov (United States)

    De Furio, Matthew; Ahn, Sang Joon; Burne, Robert A; Hagen, Stephen J

    2017-11-15

    The dental caries pathogen Streptococcus mutans is continually exposed to several types of stress in the oral biofilm environment. Oxidative stress generated by reactive oxygen species has a major impact on the establishment, persistence, and virulence of S. mutans Here, we combined fluorescent reporter-promoter fusions with single-cell imaging to study the effects of reactive oxygen species on activation of genetic competence in S. mutans Exposure to paraquat, which generates superoxide anion, produced a qualitatively different effect on activation of expression of the gene for the master competence regulator, ComX, than did treatment with hydrogen peroxide (H 2 O 2 ), which can yield hydroxyl radical. Paraquat suppressed peptide-mediated induction of comX in a progressive and cumulative fashion, whereas the response to H 2 O 2 displayed a strong threshold behavior. Low concentrations of H 2 O 2 had little effect on induction of comX or the bacteriocin gene cipB , but expression of these genes declined sharply if extracellular H 2 O 2 exceeded a threshold concentration. These effects were not due to decreased reporter gene fluorescence. Two different threshold concentrations were observed in the response to H 2 O 2 , depending on the gene promoter that was analyzed and the pathway by which the competence regulon was stimulated. The results show that paraquat and H 2 O 2 affect the S. mutans competence signaling pathway differently, and that some portions of the competence signaling pathway are more sensitive to oxidative stress than others. IMPORTANCE Streptococcus mutans inhabits the oral biofilm, where it plays an important role in the development of dental caries. Environmental stresses such as oxidative stress influence the growth of S. mutans and its important virulence-associated behaviors, such as genetic competence. S. mutans competence development is a complex behavior that involves two different signaling peptides and can exhibit cell

  6. Single Molecule Nanoelectrochemistry in Electrical Junctions.

    Science.gov (United States)

    Nichols, Richard J; Higgins, Simon J

    2016-11-15

    It is now possible to reliably measure single molecule conductance in a wide variety of environments including organic liquids, ultrahigh vacuum, water, ionic liquids, and electrolytes. The most commonly used methods deploy scanning probe microscopes, mechanically formed break junctions, or lithographically formed nanogap contacts. Molecules are generally captured between a pair of facing electrodes, and the junction current response is measured as a function of bias voltage. Gating electrodes can also be added so that the electrostatic potential at the molecular bridge can be independently controlled by this third noncontacting electrode. This can also be achieved in an electrolytic environment using a four-electrode bipotentiostatic configuration, which allows independent electrode potential control of the two contacting electrodes. This is commonly realized using an electrochemical STM and enables single molecule electrical characterization as a function of electrode potential and redox state of the molecular bridge. This has emerged as a powerful tool in modern interfacial electrochemistry and nanoelectrochemistry for studying charge transport across single molecules as a function of electrode potential and the electrolytic environments. Such measurements are possible in electrolytes ranging from aqueous buffers to nonaqueous ionic liquids. In this Account, we illustrate a number of examples of single molecule electrical measurements under electrode potential control use a scanning tunneling microscope (STM) and demonstrate how these can help in the understanding of charge transport in single molecule junctions. Examples showing charge transport following phase coherent tunneling to incoherent charge hopping across redox active molecular bridges are shown. In the case of bipyridinium (or viologen) molecular wires, it is shown how electrochemical reduction leads to an increase of the single molecule conductance, which is controlled by the liquid electrochemical

  7. Efeitos da dessecação de plantas de soja no potencial fisiológico e sanitário das sementes Effects of desiccation on the physiological potential and sanitary condition of seeds from soybean plants

    Directory of Open Access Journals (Sweden)

    André Luiz de Souza Lacerda

    2005-01-01

    Full Text Available O objetivo da pesquisa foi verificar a melhor época de aplicação de dessecantes, a fim de permitir a colheita de sementes de soja com a máxima qualidade fisiológica e sanitária. Assim, foi semeada a cultivar IAC-15 na área experimental da FE/UNESP - Campus de Ilha Solteira, localizada no município de Selvíria, MS. O delineamento experimental utilizado foi o em blocos casualizados, estando os tratamentos dispostos em esquema fatorial 3 x 3 e 4 x 4 de produtos e épocas de aplicação, nos anos agrícolas de 1996/97 e 1997/98 respectivamente. Os dessecantes utilizados no ano agrícola de 1996/97 foram o paraquat, diquat e mistura paraquat + diquat nas doses de 400, 300 e 200+150 g ha-1 respectivamente. Em 1997/98, foram utilizados os mesmos dessecantes, nas mesmas doses, acrescentando-se, nesse caso, mais um tratamento, ou seja, o produto glufosinato de amônio, na dose de 400 g ha-1. Como épocas, foram realizadas três aplicações em 1997 e quatro em 1998, todas em intervalos de cinco dias a partir do estádio R6. Nas condições ambientais em que se realizou a pesquisa, a melhor época de dessecação foi quando as plantas estavam com 80% a 90% de vagens com coloração amarela e marrom e teores de água nas sementes entre 45% e 60%. Com relação aos dessecantes, não se obteve, com qualquer dos produtos testados, potencial fisiológico e sanitário suficientes para a comercialização das sementes.The objective of this paper was to verify the ideal moment of application of desiccants on the soybeans crop, to obtain seeds with maximum physiological and sanitary quality. The cultivar IAC-15 was sowed at the experimental area of FE/UNESP - Campus of Ilha Solteira, located in the district of Selvíria, State of Mato Grosso do Sul (20º 22'S, 51º 22'W at approximately 335 m of altitude. The experimental design was a randomized block, with treatments in a factorial scheme of 3x3 and 4x4 (dessicant x application time, in 1996/97 and 1997

  8. Manejo da Planta Daninha Brachiaria plantaginea Resistente aos herbicidas Inibidores da ACCase Management of the Weed Brachiaria plantaginea Resistant to ACCase Inhibitor Herbicides

    Directory of Open Access Journals (Sweden)

    P.J. Christoffoleti

    2001-04-01

    Full Text Available O objetivo deste trabalho foi estudar o manejo de uma população da planta daninha capim-marmelada (Brachiaria plantaginea resistente aos herbicidas inibidores da ACCase (ariloxifenoxipropionatos e ciclohexanodionas, utilizados na cultura da soja no sistema de plantio direto. Para isso, foram realizados dois experimentos: um utilizando herbicidas de manejo, com mecanismos de ação alternativos, comparando a eficácia destes com os inibidores da ACCase; e outro apenas com herbicidas inibidores da ACCase e aditivos misturados à calda. As sementes resistentes foram produzidas a partir de plantas comprovadamente resistentes; para comparação de resultados, foi utilizada uma população de capim-marmelada que nunca tinha sido pulverizada com inibidores da ACCase, portanto uma população suscetível. O experimento com os herbicidas de manejo foi realizado em condições de campo, porém as plantas ficaram em caixas com capacidade de 50 L, evitando-se a disseminação destas para áreas adjacentes. Concluiu-se que as plantas resistentes não apresentam resistência múltipla com herbicidas de manejo com mecanismos de ação alternativos, podendo os herbicidas glyphosate, paraquat, sulfosate, paraquat + diuron, MSMA e glufosinate ser utilizados no período entressafra das áreas com sistema de plantio direto, para manejo de populações resistentes de capim-marmelada aos herbicidas inibidores da ACCase. O experimento com aditivos foi realizado em casa de vegetação, com plantas em vasos individuais, utilizando sementes das populações suscetíveis e resistentes. Os herbicidas utilizados foram inibidores da ACCase, em cuja calda foram adicionados aditivos nitrogenados, do tipo uréia e sulfato de amônio, além de um tratamento sem aditivos. Concluiu-se que os aditivos não alteraram a eficácia dos herbicidas inibidores da ACCase nas plantas provenientes tanto da população suscetível quanto da resistente.The objective of this research was to

  9. Soil fungi as indicators of pesticide soil pollution

    Directory of Open Access Journals (Sweden)

    Mandić Leka

    2005-01-01

    Full Text Available Soil fungi, with their pronounced enzymic activity and high osmotic potential, represent a significant indicator of negative effects of different pesticides on the agroecosystem as a whole. In that respect, a trial was set up on the alluvium soil type with the aim to investigate the effect of different herbicides (Simazine, Napropamid, Paraquat, fungicides (Captan and Mancozeb and insecticides (Fenitrothion and Dimethoate on a number of soil fungi under apple trees. The number of soil fungi was determined during four growing seasons by an indirect method of dilution addition on the Czapek agar. The study results indicate that the fungi belong to the group of microorganisms that, after an initial sensible response to the presence of pesticides in the soil, very rapidly establish normal metabolism enabling them even to increase their number. The fungicides and insecticides applied were found to be particularly effective in that respect.

  10. The role of lager beer yeast in oxidative stability of model beer

    DEFF Research Database (Denmark)

    Berner, Torben Sune; Arneborg, Nils

    2012-01-01

    that the oxidative stress resistance was strain dependent. Fermentation of model wort in European Brewing Convention tubes using three yeast strains with varying oxidative stress resistances resulted in three model beers with different rates of radical formation as measured by electron spin resonance in forced......AIMS: In this study, we investigated the relationship between the ability of lager brewing yeast strains to tolerate oxidative stress and their ability to produce oxidative stable model beer. METHODS AND RESULTS: Screening of 21 lager brewing yeast strains against diamide and paraquat showed...... in the model beers. CONCLUSIONS: A more oxidative stable beer is not obtained by a more-oxidative-stress-tolerant lager brewing yeast strain, exhibiting a higher secretion of thioredoxin, but rather by a less-oxidative-stress-tolerant strain, exhibiting a higher iron uptake. SIGNIFICANCE AND IMPACT...

  11. Manejo de plantas daninhas em maracujazeiro amarelo cultivado com adubação química e orgânica Weed management in yellow passion fruit cultivated with chemical and organic fertilization

    Directory of Open Access Journals (Sweden)

    J. Ogliari

    2007-12-01

    Full Text Available Objetivou-se, neste trabalho, avaliar diferentes formas de manejo de plantas daninhas na cultura do maracujazeiro, cultivado com adubação química e orgânica. O delineamento experimental foi em blocos casualizados, com 15 tratamentos, arranjados em esquema de parcelas subdivididas, com quatro repetições e 10 plantas úteis por parcela. Os tratamentos foram constituídos por três tipos de adubações na parcela (orgânica, química e química + orgânica e cinco manejos de plantas daninhas na subparcela (com capina, sem capina, diuron (pré + glyphosate (pós, diuron (pré + MSMA (pós e diuron (pré + (diuron + paraquat (pós. O diuron foi aplicado aos cinco dias antes do plantio das mudas, em todos os tratamentos com herbicida, variando apenas os herbicidas em pós-emergência; para cada um dos herbicidas das misturas avaliadas, foram feitas três aplicações, aos 45, 96 e 159 dias. O diuron em pré-emergência provocou sintomas de clorose nas folhas entre 20 e 26 dias após o plantio (DAP, sendo mais evidente no maracujazeiro cultivado com adubação química. Os tratamentos com diuron (pré e glyphosate (pós apresentaram melhor controle das plantas daninhas. Os tratamentos com adubação química + orgânica associados aos manejos com capina, diuron (pré + glyphosate (pós e diuron (pré + (diuron + paraquat (pós foram os que proporcionaram maior produtividade de frutos. No cultivo com adubação orgânica, o tratamento capinado foi o que proporcionou maior produtividade. No cultivo com adubação química, a produtividade foi maior no tratamento com diuron (pré + glyphosate (pós.The objective of this work was to evaluate different types of weed management in passion fruit culture under chemical and organic fertilization. The experimental design was in randomized blocks with 15 treatments, arranged in a splip-splot design, with four repetitions containing 10 plants each. The treatments consisted of three types of fertilization

  12. Toxicidade aguda de herbicidas a tilápia (Oreochromis niloticus Acute toxicity to herbicides to Oreochromis niloticus

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    R.G. Botelho

    2009-01-01

    Full Text Available Esta pesquisa teve como objetivo avaliar a sensibilidade de alevinos de Oreochromis niloticus a diversos herbicidas. Para isso, foram realizados dois ensaios, sendo, no primeiro, avaliadas concentrações de atrazina (0; 2,5; 5; 10; e 20 mg L-1, visando a determinação da concentração letal a 50% dos indivíduos (CL50, e, no segundo, a sensibilidade às mesclas dos herbicidas alachlor + atrazina (5,33 + 5,33 mg L-1, diuron + MSMA (5,33 + 2,13 mg L-1, paraquat (1,33 mg L-1 e 2,4-D + picloram (1,28 + 0,34 mg L-1, com contagem de mortes 96 horas após exposição aos produtos. No primeiro ensaio foi observado elevado declínio na sobrevivência dos alevinos a partir de 3 mg L-1 do herbicida atrazina, com CL50 estimada de 5,02 mg L-1. No segundo, a mistura alachlor + atrazina promoveu o maior efeito de mortalidade sobre os alevinos de tilápia. Com 72 horas de exposição, a escala de intoxicação evidenciou redução nos números de indivíduos de, aproximadamente, 17,4% para os produtos paraquat, 2,4-D + picloram e diuron + MSMA e de 100% para alachlor + atrazina. Os dados permitem concluir que a CL50 obtida para o atrazina é inferior àquela mencionada como tóxica para truta e que a mistura alachlor + atrazina pode ser caracterizada como de risco para O. niloticus, mesmo quando aplicada em doses normais de uso.Two assays were carried out to evaluate Oreochromis niloticus sensitivity to different herbicides. In the first experiment, atrazin concentrations (0; 2.5; 5; 10 and 20 mg L-1 were evaluated aiming to determine lethal concentration (LC50 to O. niloticus. In the second assay, the effects of the herbicide mixtures alachlor + atrazin (5.33 + 5.33 mg L-1, diuron + MSMA (5.33 + 2.13 mg L-1 , paraquat (1.33 mg L-1 and 2,4-D + picloran (1.28 + 0.34 mg L-1 , were evaluated on O. niloticus survival after 96 h of exposure. In the first assay, a sharp decrease in fingerlings survival was observed from 3 mg L-1 of atrazin with CL50 value of 5

  13. Oxidative stress and Parkinson’s Disease

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    Javier eBlesa

    2015-07-01

    Full Text Available Parkinson disease is a chronic, progressive neurological disease that is associated with a loss of dopaminergic neurons in the substantia nigra of the brain. The molecular mechanisms underlying the loss of these neurons still remain elusive. Oxidative stress is thought to play an important role in dopaminergic neurotoxicity. Complex I deficiencies of the respiratory chain account for the majority of unfavorable neuronal degeneration in Parkinson’s Disease. Environmental factors, such as neurotoxins, insecticides like rotenone, pesticides like Paraquat, dopamine itself and genetic mutations in Parkinson’s Disease related proteins contribute to mitochondrial dysfunction which precedes reactive oxygen species formation. In this mini review, we give an update of the classical pathways involving these mechanisms of neurodegeneration, the biochemical and molecular events that mediate or regulate DA neuronal vulnerability, and the role of PD-related gene products in modulating cellular responses to oxidative stress in the course of the neurodegenerative process.

  14. Influence of phytoecdysteroids and plants steroidal glycosides on the lifespan and stress resistance of drosophila melanogaster

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    Mikhail Vyacheslavovich Shaposhnikov

    2014-12-01

    Full Text Available Background. Elucidation of the molecular mechanisms of effects of the active substances of plant adaptogens is a topical area of researches. Materials and methods. We studied the effect of herbal substances containing phytoecdysteroids (20-hydroxyecdysone and inokosterone of Serratula coronata L. or steroidal glycosides (dioscin and protodioscine of Trigonella foenum-graecum L. on the expression level of stress response genes (genes of heat shock proteins, DNA repair, antioxidant defense and apoptosis, stressresistanse (paraquat, starvation, hyperthermia and lifespan of Drosophila melanogaster. Results. The studied herbal substances upregulated genes of antioxidant defense mechanisms (Sod1, but downregulated the DNA repair (XPF and Rad51 and apoptosis (Hid genes. At the same time herbal substances induced weak adaptogenic and antiaging effects. Conclusion. Our results demonstrate that the herbal substances containing phytoecdysteroids and steroidal glycosides change the expression level of stress-response genes and activate mechanisms of hormesis.

  15. Aplicação de herbicidas dessecantes em pastagens nativas construídas por differentes espécies do gênero Paspalum Application of desiccant herbicides on native pasture composed with diferent Paspalum gender

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    Miguel Vicente Weiss Ferri

    2001-08-01

    Full Text Available Com objetivo de avaliar o efeito de herbicidas dessecantes sobre pastagens nativas constituídas por diferentes espécies do gênero Paspalum, adequando-as a semeadura direta ou a sobressemeadura de espécies de interesse forrageiro, foram conduzidos três experimentos na região fisiográfica da Depressão Central do Rio Grande do Sul. No primeiro experimento, em 1995/96, avaliou-se glyphosate a 360, 720 e 1080g ha-1 de equivalente ácido, aspergido nos volumes de calda de 50 e 200 ha-1 e as espécies de Paspalum identificadas foram P. pumilum e P. notatum var. notatum biótipo "C" e "D". No segundo, em 1996, avaliou-se glyphosate a 720, 1080, 1440 e 1880g ha-1 de equivalente ácido e as espécies de Paspalum identificadas foram P. plicatulum, P. nicorae, P. notatum var. notatum biótipo "A", P. pumilum e P. maculosum. No terceiro, em 1997, avaliou-se glyphosate a 180, 270, 360, 450, 540, 720 e 1080g ha-1 de equivalente ácido e paraquat a 600 e 800g ha-1 de ingrediente ativo, e onde foram identificadas as espécies P. notatum var. saurae, P. notatum var. notatum biótipo "A" e P. pumilum. O herbicida glyphosate a 1080, 1440 e 1880g ha-1 é adequado quando se deseja controlar a pastagem nativa para introdução de semeadura direta, enquanto que glyphosate a 180, 270, 360 e 450g ha-1 e o paraquat a 600 e 800g ha-1, são adequados quando se deseja realizar a sobressemeadura de espécies forrageiras. A seleção dos herbicidas e das doses, dependerá da espécie de Paspalum dominante na pastagem nativa.The objective of this report was to evaluate the effect of desiccant herbicides on native pasture constituted of different species of the Paspalum gender, to adequate it to no-till system or to introduce forage species. Three experiments were carried out in the "Depressão Central Region" in the State of Rio Grande do Sul, Brazil. In the first, during 1995/96, glyphosate was applied in the rates of 360, 720 and 1080g ha-1 of acid equivalent, sprayed

  16. Microsomal lipid peroxidation as a mechanism of cellular damage. [Dissertation

    Energy Technology Data Exchange (ETDEWEB)

    Kornbrust, D.J.

    1979-01-01

    The NADPH/iron-dependent peroxidation of lipids in rat liver microsomes was found to be dependent on the presence of free ferrous ion and maintains iron in the reduced Fe/sup 2 +/ state. Chelation of iron by EDTA inhibited peroxidation. Addition of iron, after preincubation of microsomes in the absence of iron, did not enhance the rate of peroxidation suggesting that iron acts by initiating peroxidative decomposition of membrane lipids rather than by catalyzing the breakdown of pre-formed hydroperoxides. Liposomes also underwent peroxidation in the presence of ferrous iron at a rate comparable to intact microsomes and was stimulated by ascorbate. Carbon tetrachloride initiated lipid peroxidation in the absence of free metal ions. Rates of in vitro lipid peroxidation of microsomes and homogenates were found to vary widely between different tissues and species. The effects of paraquat on lipid peroxidation was also studied. (DC)

  17. Detection limits for real-time source water monitoring using indigenous freshwater microalgae

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Jr, Miguel [ORNL; Greenbaum, Elias [ORNL

    2009-01-01

    This research identified toxin detection limits using the variable fluorescence of naturally occurring microalgae in source drinking water for five chemical toxins with different molecular structures and modes of toxicity. The five chemicals investigated were atrazine, Diuron, paraquat, methyl parathion, and potassium cyanide. Absolute threshold sensitivities of the algae for detection of the toxins in unmodified source drinking water were measured. Differential kinetics between the rate of action of the toxins and natural changes in algal physiology, such as diurnal photoinhibition, are significant enough that effects of the toxin can be detected and distinguished from the natural variance. This is true even for physiologically impaired algae where diminished photosynthetic capacity may arise from uncontrollable external factors such as nutrient starvation. Photoinhibition induced by high levels of solar radiation is a predictable and reversible phenomenon that can be dealt with using a period of dark adaption of 30 minutes or more.

  18. EFEITOS DA QUALIDADE DA ÁGUA DE PULVERIZAÇÃO SOBRE A EFICÁCIA DE HERBICIDAS APLICADOS EM PÓS-EMERGÊNCIA EFFECT OF THE SPRAYING WATER QUALITY ON THE EFFICIENCY OF POS-EMERGENCE HERBICIDES

    Directory of Open Access Journals (Sweden)

    HAMILTON HUMBERTO RAMOS

    1998-01-01

    Full Text Available Com o objetivo de estudar o efeito da qualidade da água utilizada na pulverização, sobre a eficácia de herbicidas aplicados em pós-emergência, instalou-se um experimento no ano agrícola 91/92, em área da Fazenda Experimental da Faculdade de Ciências Agrárias e Veterinárias da UNESP, município de Jaboticabal (SP, com 21 tratamentos e três repetições. Os tratamentos foram constituídos pelas combinações de formulações comerciais de glifosate, mistura pronta de glifosate + 2,4D, MSMA e paraquat com as águas deionizada, destilada, limpa (poço profundo, turva 1 (limpa + 2 g.L-1 de solo e turva 2 (limpa + 10 g.L-1 de solo, além de uma testemunha, na qual não se efetuou a aplicação de herbicidas. Avaliações visuais de controle, geral e por espécie, aos 14, 30 e 45 dias após a aplicação, mostraram que nenhum dos tipos de água utilizados interferiu significativamente na eficiência dos herbicidas, independentemente do produto e da época de avaliação. As quantidades de argila adicionadas às águas denominadas de turva 1 e turva 2 não adsorveram os herbicidas paraquat e glifosate a ponto de prejudicar-lhes a ação. A análise e interpretação dos resultados obtidos, portanto, permitem concluir que o emprego de água turva, oriunda de um reservatório aberto, foi viável para aplicação de alguns herbicidas (glifosate, glifosate + 2,4-D, MSMA e paraquat em pós-emergência, não influenciando significativamente na sua eficácia .An experiment aiming to study the effect of the quality of the spraying water on the efficiency of pos-emergence herbicides was carried out at the Experimental Farm, Department of Agronomy, College of Agriculture and Veterinary of the UNESP, in Jaboticabal, State of São Paulo, Brazil, during the crop season of 1991/92. A randomized block design with 21 treatments and 3 replications was adopted. The treatments were commercial formulations of glyphosate; commercial mix of glyphosate + 2,4-D

  19. Semeadura direta de forrageiras de estação fria em campo natural com aplicação de herbicidas: I. Produção de forragem e contribuição relativa das espécies No-till seeding of cool season forages on native pasture with herbicides application: I. Forage yield and relative contribution of plant species

    Directory of Open Access Journals (Sweden)

    Enrique Pérez Gomar

    2004-06-01

    Full Text Available Os campos naturais apresentam estacionalidade na sua produção forrageira, a qual pode ser atenuada com a introdução de espécies de estação fria através de semeadura direta, aumentando a produção forrageira no inverno. Durante quatro anos, conduziu-se um experimento de semeadura direta de forragem de inverno, sobre campo nativo, em um Argissolo Vermelho-Amarelo, de textura superficial arenosa do norte do Uruguai. Em delineamento de blocos ao acaso com parcelas sub-subdivididas, foram testadas doses de herbicidas (glifosate 1L ha-1, glifosate 4L ha-1, paraquat 3L ha-1 e testemunha, como tratamento principal, aplicadas no ano 1994. A repetição ou não das mesmas doses no ano 1995 constituiu-se na subparcela, e a aplicação ou não das mesmas doses no ano 1996 constituiu-se na sub-subparcela. Os resultados mostraram que o maior distúrbio sobre a produção de forrageiras e contribuição das espécies do campo nativo foi provocado com a aplicação continuada de herbicidas sistêmicos na maior dose. Quando não foi aplicado herbicida (testemunha havia onze espécies e com aplicação de glifosate 4L ha-1 havia seis espécies, bem como ocorreu uma substituição de espécies perenes por anuais. O herbicida paraquat e a dose baixa de glifosate mostraram efeitos intermediários entre o observado no campo nativo semeado com triticale e azevém sem tratar com herbicida e os provocados com glifosate na dose alta. Por outro lado, os rendimentos de matéria seca das espécies forrageiras invernais semeadas foram 63% maiores na dose mais alta de glifosate do que na testemunha, devido a um maior controle da competição que exercia o campo nativo.Natural grasslands have great seasonal fluctuation of forage production. The winter forage production may be increased using cool-season forage species established with no-till, reducing seasonal fluctuations. An experiment with winter grasses (black oat and rye grass no-till sown on native grasses, was

  20. Impact of commonly used agrochemicals on bacterial diversity in cultivated soils.

    Science.gov (United States)

    Ampofo, J A; Tetteh, W; Bello, M

    2009-09-01

    The effects of three selected agrochemicals on bacterial diversity in cultivated soil have been studied. The selected agrochemicals are Cerox (an insecticide), Ceresate and Paraquat (both herbicides). The effect on bacterial population was studied by looking at the total heterotrophic bacteria presence and the effect of the agrochemicals on some selected soil microbes. The soil type used was loamy with pH of 6.0-7.0. The soil was placed in opaque pots and bambara bean (Vigna subterranean) seeds cultivated in them. The agrochemicals were applied two weeks after germination of seeds at concentrations based on manufacturer's recommendation. Plant growth was assessed by weekly measurement of plant height, foliage appearance and number of nodules formed after one month. The results indicated that the diversity index (Di) among the bacteria populations in untreated soil and that of Cerox-treated soils were high with mean diversity index above 0.95. Mean Di for Ceresate-treated soil was 0.88, and that for Paraquattreated soil was 0.85 indicating low bacterial populations in these treatment-type soils. The study also showed that application of the agrochemicals caused reduction in the number of total heterotrophic bacteria population sizes in the soil. Ceresate caused 82.50% reduction in bacteria number from a mean of 40 × 10(5) cfu g(-1) of soil sample to 70 × 10(4) cfu g(-1). Paraquat-treated soil showed 92.86% reduction, from a mean of 56 × 10(5) cfu g(-1) to 40 × 10(4) cfu g(-1). Application of Cerox to the soil did not have any remarkable reduction in bacterial population number. Total viable cell count studies using Congo red yeast-extract mannitol agar indicated reduction in the number of Rhizobium spp. after application of the agrochemicals. Mean number of Rhizobium population numbers per gram of soil was 180 × 10(4) for the untreated soil. Cerox-treated soil recorded mean number of 138 × 10(4) rhizobial cfu g(-1) of soil, a 23.33% reduction. Ceresate- and

  1. Loss of Trx-2 enhances oxidative stress-dependent phenotypes in Drosophila.

    Science.gov (United States)

    Tsuda, Manabu; Ootaka, Ryousuke; Ohkura, Chiaki; Kishita, Yoshihito; Seong, Ki-Hyeon; Matsuo, Takashi; Aigaki, Toshiro

    2010-08-04

    Overexpression of thioredoxin (TRX) confers oxidative stress resistance and extends lifespan in mammals and insects. However, less is known about phenotypes associated with loss of TRX. We investigated loss-of-function phenotypes of Trx-2 in Drosophila, and found that the mutant flies are hyper-susceptible to paraquat, a free radical generator, but not to hydrogen peroxide. They contain a high amount of protein carbonyl, which dramatically increases with age. Trx-2 mutants express high levels of anti-oxidant genes, such as superoxide dismutase, catalase, and glutathione synthetase. This is the first demonstration of biochemical and physiological consequences caused by loss of Trx-2 in Drosophila. Copyright (c) 2010 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  2. How Parkinsonian Toxins Dysregulate the Autophagy Machinery

    Directory of Open Access Journals (Sweden)

    Ruben K. Dagda

    2013-11-01

    Full Text Available Since their discovery, Parkinsonian toxins (6-hydroxydopamine, MPP+, paraquat, and rotenone have been widely employed as in vivo and in vitro chemical models of Parkinson’s disease (PD. Alterations in mitochondrial homeostasis, protein quality control pathways, and more recently, autophagy/mitophagy have been implicated in neurotoxin models of PD. Here, we highlight the molecular mechanisms by which different PD toxins dysregulate autophagy/mitophagy and how alterations of these pathways play beneficial or detrimental roles in dopamine neurons. The convergent and divergent effects of PD toxins on mitochondrial function and autophagy/mitophagy are also discussed in this review. Furthermore, we propose new diagnostic tools and discuss how pharmacological modulators of autophagy/mitophagy can be developed as disease-modifying treatments for PD. Finally, we discuss the critical need to identify endogenous and synthetic forms of PD toxins and develop efficient health preventive programs to mitigate the risk of developing PD.

  3. Toxicogenetics: In Search of Host Susceptibility to Environmental Toxicants

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    Gelareh eAlam

    2014-09-01

    Full Text Available Heavy metals, various pesticide and herbicides are implicated as risk factors for human health. Paraquat, maneb, and rotenone, carbamate and organophospherous insecticides are examples of toxicants for which acute and chronic exposure are associated with multiple neurological disorders including Parkinson’s disease (PD. Nevertheless, the role of pesticide exposure in neurodegenerative diseases is not clear-cut, as there are inconsistencies in both the epidemiological and preclinical research. The aim of this short review is to show that the inconsistencies are related to individual differences in susceptibility to the effects of neurotoxicants, individual differences that can be traced to the genetic constitution of the individuals and animals studies, i.e., host-based susceptibility.

  4. Characterization of vanadate-dependent NADH oxidation activity and isolation of yeast DNA which complements a class 1 vanadate resistance mutation

    International Nuclear Information System (INIS)

    Minasi, L.E.

    1989-01-01

    A vanadate-dependent NADH oxidation activity has been characterized in plasma membranes from the yeast S cerevisiae. NADH oxidation activity was maximally stimulated at pH 5.0 in phosphate buffer. NADH oxidation was not dependent on the concentration of plasma membranes. The vanadate-dependent NADH oxidation activity was abolished under anaerobic conditions and the concomitant uptake of oxygen occurred during NADH oxidation. The activity was inhibited by superoxide dismutase and stimulated by the presence of paraquat. These results indicate that the vanadate stimulation of NADH oxidation in yeast plasma membranes occurs as a result of the vanadate-dependent oxidation of NADH by superoxide, generated by a plasma membrane NADH oxidase. 51 V-NMR results indicated that a phosphate-vanadate anhydride was the stimulatory species in pH 5.0 and pH 7.0 phosphate buffer. Yeast DNA has been isolated which complements a class 1 vanadate resistance mutation

  5. Isolation by crystallization of translational isomers of a bistable donor-acceptor [2]catenane

    Science.gov (United States)

    Wang, Cheng; Olson, Mark A.; Fang, Lei; Benítez, Diego; Tkatchouk, Ekaterina; Basu, Subhadeep; Basuray, Ashish N.; Zhang, Deqing; Zhu, Daoben; Goddard, William A.; Stoddart, J. Fraser

    2010-01-01

    The template-directed synthesis of a bistable donor-acceptor [2]catenane wherein both translational isomers—one in which a tetrathiafulvalene unit in a mechanically interlocked crown ether occupies the cavity of a cyclobis(paraquat-p-phenylene) ring and the other in which a 1,5-dioxynaphthalene unit in the crown ether resides inside the cavity of the tetracationic cyclophane—exist in equilibrium in solution, has led to the isolation and separation by hand picking of single crystals colored red and green, respectively. These two crystalline co-conformations have been characterized separately at both the molecular and supramolecular levels, and also by dynamic NMR spectroscopy in solution where there is compelling evidence that the mechanically interlocked molecules are present as a complex mixture of translational, configurational, and conformational isomers wherein the isomerization is best described as being a highly dynamic and adaptable phenomenon. PMID:20663950

  6. The effects of drugs, other foreign compounds, and cigarette smoke on the synthesis of protein by lung slices

    International Nuclear Information System (INIS)

    Hellstern, K.; Curtis, C.G.; Powell, G.M.; Upshall, D.G.

    1990-01-01

    The incorporation of 14 C-leucine into rabbit lung slices was monitored in the absence and presence of selected drugs and chemicals relevant to the perturbation of lung function and the development of lung disease. Known inhibitors of protein synthesis (cycloheximide and ricin) inhibited the incorporation of 14 C-leucine. Marked inhibition was also recorded with the lung toxins paraquat and 4-ipomeanol. By contrast, orciprenaline, salbutamol, and terbutaline were without effect although some response was recorded with isoprenaline. The filtered gas phase of cigarette smoke and acrolein, one of its components, were inhibitory but protection was afforded by N-acetylcysteine. It is suggested that the inhibitory effects of cigarette smoke may be due to its acrolein content. It is further suggested that the use of lung slices and measurements of 14 C-leucine incorporation provide valuable means for monitoring potential pulmonary toxins

  7. Herbicide effect on 14C cellulose and 14C straw decomposition in soils. Influence of phenylcarbamates on biological activity

    International Nuclear Information System (INIS)

    Ramanujam, T.; Bellinck, Celine; Mayaudon, J.

    1979-01-01

    Aniline, 2,4-D, 2,4,5-T, simazine and paraquat have no effect on cellulose decomposition in soils. The monophenylcarbamates SN 38210, IPC and CIPC, applied at 500 ppm exert per contra an important inhibitory effect. The decomposition of straw is little influenced by the phenylcarbamates, 100 ppm of 2,4-D, 2,4,5-T or simazine significantly increase the decomposition of straw in a sandy soil. The diphenylcarbamate SN 38584 has little effect on biological activity of soils; this is strongly inhibited by application of 500 ppm of SN 38210. This inhibition may be reduced by amending the soil with lignin but addition of straw or cellulose doesn't enhance biological activity of soil. Addition of 5000 ppm of soil extract or humic acids reduces somewhat the toxicity of SN 38210 [fr

  8. In vitro sensitivity of antagonistic Trichoderma atroviride to herbicides

    Directory of Open Access Journals (Sweden)

    Patricia Helena Santoro

    2014-04-01

    Full Text Available Trichoderma atroviride was tested in vitro for its sensitivity to different herbicides. The dosages tested were recommended dosage (RD, half dosage (½RD, and double dosage (2RD. Germination, colony-forming units (CFU, radial growth, and spore production were evaluated. Carfentrazone-ethyl and sulfentrazone inhibited the germination at RD and 2RD. A reduction in the CFU was observed for glufosinate-ammonium, atrazine, carfentrazone-ethyl, diuron + paraquat dichloride, imazapyr, oxyfluorfen, and sulfentrazone at each of the tested dosages. Radial growth was influenced by ametryn, atrazine, carfentrazone-ethyl, oxyfluorfen, and sulfentrazone herbicides, with an 80% reduction of the colonial area. Spore production was affected by carfentrazone-ethyl, oxyfluorfen, and sulfentrazone with colonial area reductions of over 70%. It was concluded that 2,4 D, clomazone, and imazapyr herbicides showed the least toxicity to T. atroviride and should be used in the crops where the fungus has been applied for phytopathogen control.

  9. A Study on the Quality and Identity of Brazilian Pampa Biome Honey: Evidences for Its Beneficial Effects against Oxidative Stress and Hyperglycemia

    Directory of Open Access Journals (Sweden)

    L. C. Cruz

    2014-01-01

    Full Text Available We characterized, for the first time, the quality and identity of Brazilian Pampa biome honey and its antioxidant properties in vitro (FRAP, DDPH and ABTS. The potential protective effect of honey against oxidative stress induced by iron (Fe and paraquat, (PQ in a Drosophila melanogaster model (in vivo was also tested. The results indicated that all honey samples tested showed antioxidant activity in vitro. Flies treated with honey showed increased lifespan and were protected against oxidative stress induced by Fe and PQ. Despite the high concentration of sugars in honey (approximately 70–80%, our results demonstrate a hypoglycemic-like effect of honey in Drosophila. Thus, this study demonstrates the high quality of Brazilian Pampa biome honey as well as its significant antioxidant activity in vitro and in vivo, pointing to the potential use of this natural product as an alternative in the therapy of oxidative stress-associated diseases.

  10. A Study on the Quality and Identity of Brazilian Pampa Biome Honey: Evidences for Its Beneficial Effects against Oxidative Stress and Hyperglycemia.

    Science.gov (United States)

    Cruz, L C; Batista, J E S; Zemolin, A P P; Nunes, M E M; Lippert, D B; Royes, L F F; Soares, F A; Pereira, A B; Posser, T; Franco, J L

    2014-01-01

    We characterized, for the first time, the quality and identity of Brazilian Pampa biome honey and its antioxidant properties in vitro (FRAP, DDPH and ABTS). The potential protective effect of honey against oxidative stress induced by iron (Fe) and paraquat, (PQ) in a Drosophila melanogaster model (in vivo) was also tested. The results indicated that all honey samples tested showed antioxidant activity in vitro. Flies treated with honey showed increased lifespan and were protected against oxidative stress induced by Fe and PQ. Despite the high concentration of sugars in honey (approximately 70-80%), our results demonstrate a hypoglycemic-like effect of honey in Drosophila. Thus, this study demonstrates the high quality of Brazilian Pampa biome honey as well as its significant antioxidant activity in vitro and in vivo, pointing to the potential use of this natural product as an alternative in the therapy of oxidative stress-associated diseases.

  11. UV inactivation: Combined effects of UV radiation and xenobiotics in two strains of Saccharomyces

    International Nuclear Information System (INIS)

    Lochmann, E.R.; Lochmann, G.

    1997-01-01

    The effects of eight chemicals on the inactivation rate of ultraviolet radiation on the colony building capabilities of two strains of Saccharomyces cervisae - a wild type strain and a mutant deficient in excision repair - were studied. The insecticide methoxychlor, the herbicide 2,4-dichlorophenoxyacetic acid, the fungicide pentachlorophenol and its metabolite tetrachlorohydroquinone, as well as the chemicals acrylonitrile and 2,3-dichloro-1-propene have no significant impact on the effects of UV radiation in Saccharomyces cerevisae. Depending on the concentration, trichloroethylene increases the sensitivity to UV radiation. The herbicide paraquat provides efficient protection against UV radiation at concentrations where a toxic effect cannot be observed even without UV. The results were rather similar for both strains. (orig.) [de

  12. Risk factors for acute pesticide poisoning in Sri Lanka

    DEFF Research Database (Denmark)

    van der Hoek, Wim; Konradsen, Flemming

    2005-01-01

    This report describes the characteristics of patients with acute pesticide poisoning in a rural area of Sri Lanka and, for intentional self-poisoning cases, explores the relative importance of the different determinants. Data were collected for 239 acute pesticide-poisoning cases, which were...... admitted to two rural hospitals in Sri Lanka. Sociodemographic characteristics, negative life events and agricultural practices of the intentional self-poisoning cases were compared with a control group. Most cases occurred among young adults and the large majority (84%) was because of intentional self-poisoning....... Case fatality was 18% with extremely high case fatality for poisoning with the insecticide endosulfan and the herbicide paraquat. Cases were generally younger than controls, of lower educational status and were more often unemployed. No agricultural risk factors were found but a family history...

  13. Contribution to the study of solvated electrons in water and alcohols and of radiolytic processes in organic carbonates by picosecond pulse radiolysis

    International Nuclear Information System (INIS)

    Torche, Faycal

    2012-01-01

    This work is part of the study area of the interaction of radiation with polar liquids. Using the picosecond electron accelerator ELYSE, studies were conducted using the techniques of pulse radiolysis combined with absorption spectrophotometry Time-resolved in the field of a picosecond. This work is divided into two separate chapters. The first study addresses the temporal variation of the radiolytic yield of solvated electron in water and simple alcohols. Due to original detection system mounted on the accelerator ELYSE, composed of a flash lamp specifically designed for the detection and a streak-camera used for the first time in absorption spectroscopy, it was possible to record the time-dependent radiolytic yields of the solvated electron from ten picoseconds to a few hundred nanoseconds. The scavenging of the electron solvated by methyl viologen, was utilized to reevaluate the molar extinction coefficient of the absorption spectrum of solvated electron in water and ethanol from isobestic points which corresponds to the intersection of the absorption spectra of solvated electron which disappears and methyl viologen which is formed during the reaction. The second chapter is devoted to the study of liquid organic carbonates such as dimethyl carbonate (DMC), diethyl carbonate (DEC) and propylene carbonate (PC). This family of carbonate which compose the electrolytes lithium batteries, has never been investigated by pulse radiolysis. The studies were focused on the PC in the light of these physicochemical characteristics, including its very high dielectric constant and its strong dipole moment of 4.9 D. The first results were obtained on aqueous solutions containing propylene carbonate to observe the reactions of reduction and oxidation of PC by radiolytic species of water (solvated electron and OH radicals). Then, after the identification (spectral and kinetic) of the species formed by interaction with the OH radical as the PC* radical resulting from the

  14. Host-Guest Recognition-Assisted Electrochemical Release: Its Reusable Sensing Application Based on DNA Cross Configuration-Fueled Target Cycling and Strand Displacement Reaction Amplification.

    Science.gov (United States)

    Chang, Yuanyuan; Zhuo, Ying; Chai, Yaqin; Yuan, Ruo

    2017-08-15

    In this work, an elegantly designed host-guest recognition-assisted electrochemical release was established and applied in a reusable electrochemical biosensor for the detection of microRNA-182-5p (miRNA-182-5p), a prostate cancer biomarker in prostate cancer, based on the DNA cross configuration-fueled target cycling and strand displacement reaction (SDR) amplification. With such a design, the single target miRNA input could be converted to large numbers of single-stranded DNA (S1-Trp and S2-Trp) output, which could be trapped by cucurbit[8]uril methyl viologen (CB-8-MV 2+ ) based on the host-guest recognition, significantly enhancing the sensitivity for miRNA detection. Moreover, the nucleic acids products obtained from the process of cycling amplification could be utilized sufficiently, avoiding the waste and saving the experiment cost. Impressively, by resetting a settled voltage, the proposed biosensor could release S1-Trp and S2-Trp from the electrode surface, attributing that the guest ion methyl viologen (MV 2+ ) was reduced to MV +· under this settled voltage and formed a more-stable CB-8-MV +· -MV +· complex. Once O 2 was introduced in this system, MV +· could be oxidized to MV 2+ , generating the complex of CB-8-MV 2+ for capturing S1-Trp and S2-Trp again in only 5 min. As a result, the simple and fast regeneration of biosensor for target detection was realized on the base of electrochemical redox-driven assembly and release, overcoming the challenges of time-consuming, burdensome operations and expensive experimental cost in traditional reusable biosensors and updating the construction method for a reusable bisensor. Furthermore, the biosensor could be reused for more than 10 times with a regeneration rate of 93.20%-102.24%. After all, the conception of this work provides a novel thought for the construction of effective reusable biosensor to detect miRNA and other biomarkers and has great potential application in the area requiring the release of

  15. Generation and reactivity of ketyl radicals with lignin related structures. On the importance of the ketyl pathway in the photoyellowing of lignin containing pulps and papers.

    Science.gov (United States)

    Fabbri, Claudia; Bietti, Massimo; Lanzalunga, Osvaldo

    2005-04-01

    [reaction: see text] Ketyl radicals with lignin related structures have been generated by means of radiation chemical and photochemical techniques. In the former studies ketyl radicals are produced by reaction of alpha-carbonyl-beta-aryl ether lignin models with the solvated electron produced by pulse radiolysis of an aqueous solution at pH 6.0. The UV-vis spectra of ketyl radicals are characterized by three main absorption bands. The shape and position of these bands slightly change when the spectra are recorded in alkaline solution (pH 11.0) being now assigned to the ketyl radical anions and a pKa = 9.5 is determined for the 1-(3,4,5-trimethoxyphenyl)-2-phenoxyethanol-1-yl radical. Decay rates of ketyl radicals are found to be dose dependent and, at low doses, lie in the range (1.7-2.7) x 10(3) s(-1). In the presence of oxygen a fast decay of the ketyl radicals is observed (k2 = 1.8-2.7 x 10(9) M(-1) s(-1)) that is accompanied by the formation of stable products, i.e., the starting ketones. In the photochemical studies ketyl radicals have been produced by charge-transfer (CT) photoactivation of the electron donor-acceptor salts of methyl viologen (MV2+) with alpha-hydroxy-alpha-phenoxymethyl-aryl acetates. This process leads to the instantaneous formation of the reduced acceptor (methyl viologen radical cation, MV+*), as is clearly shown in a laser flash photolysis experiment by the two absorption bands centered at 390 and 605 nm, and an acyloxyl radical [ArC(CO2*))(OH)CH2(OC6H5)], which undergoes a very fast decarboxylation with formation of the ketyl radicals. Steady-state photoirradiation of the CT ion pairs indicates that 1-aryl-2-phenoxyethanones are formed as primary photoproducts by oxidation of ketyl radicals by MV2+ (under argon) or by molecular oxygen. Small amounts of acetophenones are formed by further photolysis of 1-aryl-2-phenoxyethanones and not by beta-fragmentation of the ketyl radicals. The high reactivity of ketyl radicals with oxygen coupled

  16. The Synergism of Chemical Herbicides and Aureobasidium pullulans for Control Cleavers (Galium aparine L.) in Wheat

    Institute of Scientific and Technical Information of China (English)

    Liang CHENG

    2015-01-01

    Aureobasidium pul ulans, a biocontrol agent for the annual weed Galium aparine L. was evaluated in vitro for its compatibility with commercial formulation of five herbicides at 1X (recommended field rate), 0.5X, 0.2X, 0.1X, 0.067X, and 0.05X concentrations. Germination of A. pul ulans with paraquat, 2, 4-D, quizalofop-p, and clethodim treatment appeared reduced compared with germination of A. pul ulans with fluroxypyr treatment at al concentrations. Stunted and shorter germ tubes in comparison with the control were observed with 2, 4-D, quizalofop-p, and clethodim at 0.2X. Al concentration of paraquat, 2, 4-D, quizalofop-p, and clethodim except 0.05X, significantly decreased radial growth of A. pul ulans compared with its growth on the untreated PDA medium. Field trials to further develop A. pul ulans as bio-control agent for control G. aparine L. was conducted to test the effectiveness of this fungus in wheat plots for 2 years at the same location in Xining. Treatments included spore suspensions of A. pul ulans alone, a mixture of both fungus and fluroxypyr in wheat. Biocontrol agent effectiveness was estimated at approximately 7 and 14 days after treatment, as disease incidence, percent weed control, and weed biomass reduction. Significant reduction in weed biomass occurred in combination treatments, and potential exists to tank mix A. pul ulans with fluroxypyr. Leaf surface moisture and air temperatures fol owing application may account for inconsistencies in field results between years. This fungal organisms show potential as bioherbicides for weeds in G. aparine L.

  17. Chemical desiccation for early harvest in soybean cultivars

    Directory of Open Access Journals (Sweden)

    Tamara Pereira

    2015-08-01

    Full Text Available The use of desiccants is an alternative to anticipate the soybean harvest and keep the physiological quality of seed. The objective of this work was to assess the production performance and germination seeds in response to differents stages and desiccation chemicals products to early harvest of soybean cultivars. The experiment was conducted in Campos Novos, in two harvests, it was used a randomized complete block design disposed in split-split-plots. Two phenological stages of application (stage R7.1 and R7.3 were tested in the main plot. Five soybean cultivars (NA 5909 RG, CD 2585 RR, BMX Turbo RR, SYN 1059 RR and BENSO 1RR were evaluated in the subplots, and three desiccants ammonium glufosinate, paraquat, carfentrazone-ethyl in the 2011/12 season and one control (without the desiccant application were evaluated in the sub-subplots. In the 2012/13 season the carfentrazone-ethyl was substituted by diquat. It were evaluated the number of the days in the early harvest, yield, number of pods per plant, number of seeds per pod, mass of 100 seeds and germination percentage. The chemical dessecation with the use of glufosinate ammonium and paraquat applied in R7.1 stage allowed to anticipate the harvest in six days (2011/12 and provided maintenance germination percentage (90% and 92% compared to control (76%. The dessecation didn’t influence negatively on seeds productivity, but reduced the mass of seeds in the two growing seasons, and early harvest was dependent of pre-harvest rain absence, with this preamble. The use of dessicants is a possibility of early harvest in production field of soybean seeds.

  18. Gene expression as a sensitive endpoint to evaluate cell differentiation and maturation of the developing central nervous system in primary cultures of rat cerebellar granule cells (CGCs) exposed to pesticides

    International Nuclear Information System (INIS)

    Hogberg, Helena T.; Kinsner-Ovaskainen, Agnieszka; Hartung, Thomas; Coecke, Sandra; Bal-Price, Anna K.

    2009-01-01

    The major advantage of primary neuronal cultures for developmental neurotoxicity (DNT) testing is their ability to replicate the crucial stages of neurodevelopment. In our studies using primary culture of cerebellar granule cells (CGCs) we have evaluated whether the gene expression relevant to the most critical developmental processes such as neuronal differentiation (NF-68 and NF-200) and functional maturation (NMDA and GABA A receptors), proliferation and differentiation of astrocytes (GFAP and S100β) as well as the presence of neural precursor cells (nestin and Sox10) could be used as an endpoint for in vitro DNT. The expression of these genes was assessed after exposure to various pesticides (paraquat parathion, dichlorvos, pentachlorophenol and cycloheximide) that could induce developmental neurotoxicity through different mechanisms. All studied pesticides significantly modified the expression of selected genes, related to the different stages of neuronal and/or glial cell development and maturation. The most significant changes were observed after exposure to paraquat and parathion (i.e. down-regulation of mRNA expression of NF-68 and NF-200, NMDA and GABA A receptors). Similarly, dichlorvos affected mainly neurons (decreased mRNA expression of NF-68 and GABA A receptors) whereas cycloheximide had an effect on neurons and astrocytes, as significant decreases in the mRNA expression of both neurofilaments (NF-68 and NF-200) and the astrocyte marker (S100β) were observed. Our results suggest that toxicity induced by pesticides that target multiple pathways of neurodevelopment can be identified by studying expression of genes that are involved in different stages of cell development and maturation, and that gene expression could be used as a sensitive endpoint for initial screening to identify the compounds with the potential to cause developmental neurotoxicity

  19. Reversible oxidative modification: a key mechanism of Na+-K+ pump regulation.

    Science.gov (United States)

    Figtree, Gemma A; Liu, Chia-Chi; Bibert, Stephanie; Hamilton, Elisha J; Garcia, Alvaro; White, Caroline N; Chia, Karin K M; Cornelius, Flemming; Geering, Kaethi; Rasmussen, Helge H

    2009-07-17

    Angiotensin II (Ang II) inhibits the cardiac sarcolemmal Na(+)-K(+) pump via protein kinase (PK)C-dependent activation of NADPH oxidase. We examined whether this is mediated by oxidative modification of the pump subunits. We detected glutathionylation of beta(1), but not alpha(1), subunits in rabbit ventricular myocytes at baseline. beta(1) Subunit glutathionylation was increased by peroxynitrite (ONOO(-)), paraquat, or activation of NADPH oxidase by Ang II. Increased glutathionylation was associated with decreased alpha(1)/beta(1) subunit coimmunoprecipitation. Glutathionylation was reversed after addition of superoxide dismutase. Glutaredoxin 1, which catalyzes deglutathionylation, coimmunoprecipitated with beta(1) subunit and, when included in patch pipette solutions, abolished paraquat-induced inhibition of myocyte Na(+)-K(+) pump current (I(p)). Cysteine (Cys46) of the beta(1) subunit was the likely candidate for glutathionylation. We expressed Na(+)-K(+) pump alpha(1) subunits with wild-type or Cys46-mutated beta(1) subunits in Xenopus oocytes. ONOO(-) induced glutathionylation of beta(1) subunit and a decrease in Na(+)-K(+) pump turnover number. This was eliminated by mutation of Cys46. ONOO(-) also induced glutathionylation of the Na(+)-K(+) ATPase beta(1) subunit from pig kidney. This was associated with a approximately 2-fold decrease in the rate-limiting E(2)-->E(1) conformational change of the pump, as determined by RH421 fluorescence. We propose that kinase-dependent regulation of the Na(+)-K(+) pump occurs via glutathionylation of its beta(1) subunit at Cys46. These findings have implications for pathophysiological conditions characterized by neurohormonal dysregulation, myocardial oxidative stress and raised myocyte Na(+) levels.

  20. Oxidative stress contributes to outcome severity in a Drosophila melanogaster model of classic galactosemia

    Directory of Open Access Journals (Sweden)

    Patricia P. Jumbo-Lucioni

    2013-01-01

    Classic galactosemia is a genetic disorder that results from profound loss of galactose-1P-uridylyltransferase (GALT. Affected infants experience a rapid escalation of potentially lethal acute symptoms following exposure to milk. Dietary restriction of galactose prevents or resolves the acute sequelae; however, many patients experience profound long-term complications. Despite decades of research, the mechanisms that underlie pathophysiology in classic galactosemia remain unclear. Recently, we developed a Drosophila melanogaster model of classic galactosemia and demonstrated that, like patients, GALT-null Drosophila succumb in development if exposed to galactose but live if maintained on a galactose-restricted diet. Prior models of experimental galactosemia have implicated a possible association between galactose exposure and oxidative stress. Here we describe application of our fly genetic model of galactosemia to the question of whether oxidative stress contributes to the acute galactose sensitivity of GALT-null animals. Our first approach tested the impact of pro- and antioxidant food supplements on the survival of GALT-null and control larvae. We observed a clear pattern: the oxidants paraquat and DMSO each had a negative impact on the survival of mutant but not control animals exposed to galactose, and the antioxidants vitamin C and α-mangostin each had the opposite effect. Biochemical markers also confirmed that galactose and paraquat synergistically increased oxidative stress on all cohorts tested but, interestingly, the mutant animals showed a decreased response relative to controls. Finally, we tested the expression levels of two transcripts responsive to oxidative stress, GSTD6 and GSTE7, in mutant and control larvae exposed to galactose and found that both genes were induced, one by more than 40-fold. Combined, these results implicate oxidative stress and response as contributing factors in the acute galactose sensitivity of GALT-null Drosophila and, by