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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 poisoning

    Science.gov (United States)

    ... please enable JavaScript. Paraquat (dipyridylium) is a highly toxic weed killer (herbicide). In the past, the United States encouraged Mexico to use it to destroy marijuana plants. Later, research showed this herbicide was dangerous to ...

  3. 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.

  4. Xuebijing for paraquat poisoning.

    Science.gov (United States)

    Deng, Jin; Huo, Dongmei; Wu, Qiaoyuan; Zhu, Lin; Liao, Yunhua

    2013-07-29

    At present, there is a lack of effective treatments for paraquat poisoning. Xuebijing injection is a complex traditional Chinese prescription consisting of Flos Carthami, Radix Paeoniae Rubra, Rhizoma Chuanxiong, Radix Salviae Miltiorrhizae and Radix Angelicae Sinensis. Although clinical experience suggests that Xuebijing injection might have potential in the management of paraquat poisoning, there is no conclusion on the effectiveness of this treatment. To assess the effects of Xuebijing injection in patients with paraquat poisoning. We searched the Cochrane Injuries Group's Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE (OvidSP), EMBASE (OvidSP), CINAHL (EBSCO), ISI Web of Science: Science Citation Index Expanded, ISI Web of Science: Conference Proceedings Citation Index-Science, Chinese bio-medical literature and retrieval system (CBM), China National Knowledge Infrastructure Database (CNKI), and the Traditional Chinese Medicine Database. The search was run on the 29th May 2013. We included all randomised controlled trials (RCTs) comparing Xuebijing injection combined with conventional care against conventional care alone. Two or three authors independently selected studies, assessed study quality and extracted data. We calculated the mortality risk ratio (RR) and 95% confidence interval (CI). Data on all-cause mortality at the end of follow-up were summarised in a meta-analysis. We identified two trials including 84 people. Although there were fewer deaths in people treated with Xuebijing injection, meta-analysis showed that it did not provide a statistically significant benefit in reducing all-cause mortality in people with paraquat poisoning as compared to control (RR 0.71; 95% CI 0.48 to 1.04; P = 0.08). Based on the findings of two small RCTs, Xuebijing injection did not have a statistically significant benefit on reducing all-cause mortality in people with paraquat poisoning. However, both

  5. 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.

  6. Medical management of paraquat ingestion.

    Science.gov (United States)

    Gawarammana, Indika B; Buckley, Nicholas A

    2011-11-01

    Poisoning by paraquat herbicide is a major medical problem in parts of Asia while sporadic cases occur elsewhere. The very high case fatality of paraquat is due to inherent toxicity and lack of effective treatments. We conducted a systematic search for human studies that report toxicokinetics, mechanisms, clinical features, prognosis and treatment. Paraquat is rapidly but incompletely absorbed and then largely eliminated unchanged in urine within 12-24 h. Clinical features are largely due to intracellular effects. Paraquat generates reactive oxygen species which cause cellular damage via lipid peroxidation, activation of NF-κB, mitochondrial damage and apoptosis in many organs. Kinetics of distribution into these target tissues can be described by a two-compartment model. Paraquat is actively taken up against a concentration gradient into lung tissue leading to pneumonitis and lung fibrosis. Paraquat also causes renal and liver injury. Plasma paraquat concentrations, urine and plasma dithionite tests and clinical features provide a good guide to prognosis. Activated charcoal and Fuller's earth are routinely given to minimize further absorption. Gastric lavage should not be performed. Elimination methods such as haemodialysis and haemoperfusion are unlikely to change the clinical course. Immunosuppression with dexamethasone, cyclophosphamide and methylprednisolone is widely practised, but evidence for efficacy is very weak. Antioxidants such as acetylcysteine and salicylate might be beneficial through free radical scavenging, anti-inflammatory and NF-κB inhibitory actions. However, there are no published human trials. The case fatality is very high in all centres despite large variations in treatment. © 2011 The Authors. British Journal of Clinical Pharmacology © 2011 The British Pharmacological Society.

  7. Multiple resistance of horseweed to glyphosate and paraquat and its control with paraquat and metribuzin combinations

    Science.gov (United States)

    Greenhouse and field studies were conducted in 2007 and 2008 to investigate possible multiple-resistance of horseweed to paraquat and glyphosate, and to evaluate the effect of the addition of metribuzin to paraquat on control of paraquat-resistant horseweed. Results indicated that the GR50 (herbicid...

  8. Potential dependent structures of adsorbed viologens on Cu(100)

    Energy Technology Data Exchange (ETDEWEB)

    Gentz, Knud; Broekmann, Peter; Kossmann, Simone; Kirchner, Barbara; Wandelt, Klaus [Institut fuer Physikalische und Theoretische Chemie, Univ. Bonn (Germany)

    2007-07-01

    The structures of two different viologens (1,1'-disubstituted 4,4'Bipyridins) adsorbed on a bromide-modified Cu(100) surface in an electrochemical environment have been studied by cyclic voltammetry (CV) and Scanning Tunneling Microscope (STM) studies. Upon adsorption, both viologens arrange in characteristic structures, dependent on the potential of the electrochemical cell. Via potential variation various structures are accessible and have been characterized. The phase transition are completely reversible between the DBV{sup 2+} dication and the DBV{sup .+}radical cation of Dibenzylviologen and the DPV{sup 2+}and DPV{sup .+} of the Diphenylviologen respectively. For the DPV molecule, this phase transition proceeds in two steps. First, the bulk phase is oxidized through the adsorbed layer of the DPV{sup .+} radical cation. Only at a significantly higher potential the adsorbed viologen is oxidized. In the cathodic sweep a corresponding surface reduction peak can be observed in the cv at higher potential than the bulk reduction peak. The reduction to the neutral DBV and DPV molecules occurs only at low potentials beyond the onset of the hydrogen evolution reaction. Based on DFT calculations of the structure of individual and groups of Viologen molecules, models for the observed structures are proposed.

  9. 77 FR 47539 - Paraquat Dichloride; Pesticide Tolerances

    Science.gov (United States)

    2012-08-09

    ... found at http://www.regulations.gov in document ``Paraquat Dichloride. Human Health ] Risk Assessment... and Endpoints for Paraquat for Use in Human Health Risk Assessment Point of departure RfD, PAD, LOC...%; kiwifruit, 30%; lemons, 2.5%; lettuce, 1%; ] nectarines, 10%; olives, 5%; onions, 5%; oranges, 5%; pasture...

  10. Pulse Radiolysis of Methyl Viologen in Aqueous Solutions

    DEFF Research Database (Denmark)

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

    1982-01-01

    Pulse radiolysis of air-free aqueous methyl viologen (MV2+) solutions was carried out at various pH. The attack of e–aq on MV2+, with k(e–aq+ MV2+)= 7.5 × 1010 dm3 mol–1 s–1, leads to the formation of the long-lived radical cation (MV˙+), which possesses two absorption maxima at 392.5 nm (ε392...

  11. A clinical survey of paraquat formulation workers.

    Science.gov (United States)

    Howard, J K

    1979-08-01

    A group of 18 male Caucasian workers from the United Kingdom and a further group of 18 male mixed race (mainly Malay) workers from Malaysia employed in the formulation of paraquat-based herbicides were examined for evidence of chronic ill health after long-term exposure to paraquat. Clinical records were examined, medical and occupational histories were obtained and a clinical examination, particularly of the skin, was undertaken. Skin rashes, nail damage and epistaxes were encountered by most workers as a result of direct contact of skin and mucous membranes with paraquat. These conditions subsided rapidly and no worker reported any sequelae. There was no clinical evidence of long-term effects on skin, mucous membranes or general health following exposure to paraquat over several years in these workers.

  12. Multiple Resistance of Horseweed to Glyphosate and Paraquat and Its Control with Paraquat and Metribuzin Combinations

    Directory of Open Access Journals (Sweden)

    Daniel H. Poston

    2012-12-01

    Full Text Available Greenhouse and field studies were conducted in 2007 and 2008 to investigate possible multiple-resistance of horseweed to paraquat and glyphosate, and to evaluate the effect of the addition of metribuzin to paraquat on control of paraquat-resistant horseweed. Results indicated that the GR50 (herbicide dose required to cause a 50% reduction in plant growth value for the susceptible population S102 was 0.066 kg ae/ha glyphosate, and for the resistant population MDOT was 0.78 kg/ha glyphosate. The level of glyphosate resistance for MDOT was 12-fold compared with S102. The GR50 value for the susceptible population S102 was 0.078 kg ai/ha paraquat, and for the resistant population MDOT was 0.67 kg/ha paraquat. The level of paraquat resistance for MDOT was 9-fold compared to S102, suggesting multiple-resistance to glyphosate and paraquat in the MDOT population. In field studies the addition of metribuzin to paraquat improved horseweed control.

  13. PENGARUH PARAQUAT TERHADAP BAKTERI TANAH, Rhizobium sp. (Influence of Paraquat Herbicide on Soil Bacteria Rhizobium Sp.

    Directory of Open Access Journals (Sweden)

    Erni Martani

    2001-08-01

    Full Text Available ABSTRAK Pencemaran pestisida merupakan salah satu masalah lingkungan yang menyebabkan gangguan terhadap organisme tanah. Paraquat adalah bahan aktif beberapa jenis herbisida yang banyak diaplikasikan di lahan gambut dan lahan pertanian tadah hujan. Studi ini dilakukan untuk mengetahui pengaruh herbisida paraquat terhadap bakteri Rhizobium sp. Tiga puluh lima strain Rhizobium sp. telah diuji dengan menggunakan teknik difusi cakram kertas (paper disc. Sebagian strain adalah hasil isolasi dari ranah, bintil akar tanaman Ieguminosa dan inokulum leguminosa (Legin - Iegume Inoculum. Enam strain lain aclalah bakteri Rhizobium japonicum. Hasil penelitian menunjukkan hahwa paraquat memiliki daya hambat terhadap hakteri Rhizohium sp. Sebanyak 17,14% (enam strain dari seluruh strain yang diuji, tidak mengalami penghambatan sampai konsentrasi paraquat 400 ppm. Bakteri ini memiliki prospek bagus untuk digunakan sebagai inokulum rhizobium terutama di lahan pertanian yang telah tercemari herbisida, khususnya yang mempunyai bahan aktif paraquat. Sebagian besar strain yang digunakan (82,86% terhambat oleh 20 ppm parakuat dan daya hambat tersebut makin besar seiring dengan meningkatnya konsentrasi paraquat. Mengingat makin meluasnya pemakaian herbisida berbahan aktif paraquat di Indonesia dan peran Rhizobium dalam fiksasi nitrogen, hasil penelitian ini fiksasi memiliki arti penting, terutama bagi petani agar berhati-hati dalam pemakaian pestisida.   ABSTRACT Pesticedes may cause environmental pollution which lead to disturbance of soil biota. Paraquat is an active agent of herbicides usually used in peat land and rainfed agriculture. This research was conducted to examine the influence of paraquat on symbiotic nitrogen fixing bacteria, Rhizobium sp. Thirty five trains of the genus Rhizobium were examined in this research. Some of them were isolated from soils, legume root nodules, and legume Inoculum. Six stains of Rhizobium japonicum were also used in this

  14. Acute kidney injury following Paraquat poisoning in India.

    Science.gov (United States)

    Pavan, Malleshappa

    2013-01-01

    Paraquat is highly toxic to human and is widely used in agriculture as a contact herbicide. Paraquat poisoning is associated with high mortality varying from 35% to 50%. Six cases of paraquat poisoning were treated in our center. Acute kidney injury developed in all the cases and mortality was 66%. Respiratory and multiorgan failure are the main causes for mortality.

  15. DNA photocleavage by a supramolecular Ru(II)-viologen complex.

    Science.gov (United States)

    Fu, Patty K-L; Bradley, Patricia M; van Loyen, Dietmar; Dürr, Heinz; Bossmann, Stefan H; Turro, Claudia

    2002-07-29

    A novel Ru(II) complex possessing two sequentially linked viologen units, Ru-V(1)-V(2)(6+), was synthesized and characterized. Upon excitation of the Ru(II) unit (lambda(exc) = 532 nm, fwhm approximately 10 ns), a long-lived charge-separated (CS) state is observed (tau = 1.7 micros) by transient absorption spectroscopy. Unlike Ru(bpy)(3)(2+), which cleaves DNA upon photolysis through the formation of reactive oxygen species, such as (1)O(2) and O(2)(-), the photocleavage of plasmid DNA by Ru-V(1)-V(2)(6+) is observed both in air and under N(2) atmosphere (lambda(irr) > 395 nm).

  16. Radiochromic film containing methyl viologen for radiation dosimetry

    DEFF Research Database (Denmark)

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

    2007-01-01

    concentrations of the dye have been studied. The absorbance values at selected wavelengths, obtained from irradiation of the PVA film containing the most suitable MV2+ concentration, can be satisfactorily related to the absorbed dose over a wide range, from 50 Gy up to 40 kGy. The effects of dose, dose rate......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...

  17. Efectos del herbicida Paraquat sobre el zooplancton

    Directory of Open Access Journals (Sweden)

    Gagneten Ana María

    2002-01-01

    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.

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

    African Journals Online (AJOL)

    ... 1971. lnvloed van die onkruiddoder paraquat op die terughouding van voedingstowwe tn Pennisetrum clondestinum, Eragrostis cuntuh en Eragrostis planiculmus. Unpub.Rep.Dept. Agric. Tech. Services. NEL, J.W., 1964. Die voedingswaarde van Eragrostis curvula as hooi-en weidingsgewas vir skape. Dept. L.T.D. Teg.

  19. 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.

  20. 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.

  1. Novel Viologen Derivative Based Uranyl Coordination Polymers Featuring Photochromic Behaviors.

    Science.gov (United States)

    Hu, Kong-Qiu; Wu, Qun-Yan; Mei, Lei; Zhang, Xiao-Lin; Ma, Lei; Song, Gang; Chen, Di-Yun; Wang, Yi-Tong; Chai, Zhi-Fang; Shi, Wei-Qun

    2017-12-19

    A series of novel uranyl coordination polymers have been synthesized by hydrothermal reactions. Both complexes 1 and 2 prosess two ipbp - ligands (H 2 ipbpCl=1-(3,5-dicarboxyphenyl)-4,4'-bipyridinium chloride), one uranyl cation, and two coordination water molecules, which can further extend to 2D networks through hydrogen bonding. In complex 1, two sets of equivalent nets are entangled together, resulting in a 2D + 2D → 3D polycatenated framework. In complex 2, the neighbouring equivalent nets interpenetrate each other, forming a twofold interpenetrated network. Complexes 3 and 4 are isomers, and both of them are constructed from (UO 2 ) 2 (OH) 2 dinuclear units, which are connected with four ipbp - ligands. The 3D structures of complexes 3 and 4 are similar along the b axis. Similar to other viologen-based coordination polymers, complexes 3 and 4 exhibit photochromic and thermochromic properties, which are rarely observed in actinide coordination polymers. Unlike the monotonous coordination mode in complexes 1-4, the ipbp - ligands feature a μ 3 -bridge through two kinds of coordination modes in complex 5. Notably, complex 5 presents a unique example in which terminal pyridine nitrogen atom is involved in the coordination. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Paraquat poisoning: A case report and review of literature

    Directory of Open Access Journals (Sweden)

    Kondle Raghu

    2013-01-01

    Full Text Available Paraquat (1, r-dimethyl-4,4′-bipyridium dichloride, a brown syrupy liquid is an effective herbicide that has low chronic toxicity because of its rapid deactivation on contact with soil. A high dose of paraquat or severe poisoning has a poor prognosis. At present there is no specific antidote to paraquat poisoning, hence the need to focus on prevention and in case of exposure or ingestion, aggressive decontamination to prevent further absorption. Although uncommon, paraquat ingestion can lead to severe and often fatal toxicity. However, despite its widespread availability, reports of this herbicide poisoning in India are uncommon.

  3. Fatality due to paraquat intoxication: confirmation by postmortem tissue analysis.

    Science.gov (United States)

    Conradi, S E; Olanoff, L S; Dawson, W T

    1983-11-01

    A brief case report is presented describing a patient who unknowingly ingested a fatal amount of paraquat, presumably mixed in some illicit moonshine alcohol. Despite an initial clinical presentation typical of paraquat intoxication, the herbicide was absent upon analysis of multiple urine and blood specimens, and the diagnosis was confirmed only postmortem after determination of high paraquat tissue concentrations in all the major organs. Autopsy results are presented along with a discussion of the histopathologic changes observed in the lungs, liver, and kidneys. Because the combination of toxicologic sequelae attributable to acute paraquat poisoning is fairly unique to this agent, the diagnosis must be suspected highly early in the clinical course of such cases and appropriate therapy initiated, despite the inability to isolate paraquat on preliminary laboratory screening.

  4. Paraquat and pine trees in east Tennessee

    Energy Technology Data Exchange (ETDEWEB)

    Schnell, R.L.; Toennisson, R.L.

    1978-01-01

    The Tennessee Valley Authority started a series of 8% Paraquat tests in east Tennessee on loblolly, shortleaf, and Virginia pines in the spring of 1974. In addition to species, we are also testing the effects of season of treatment application and the length of time between the completed treatment and the harvest cut. Wood samples are being analyzed by the Botany Department at the University of Tennessee in Knoxville. All three species have shown increased oleoresin production. Season of treatment did not have a significant effect on enhancement nor did length of time between treatment and harvest.

  5. Mesoporous Silica Thin Films for Improved Electrochemical Detection of Paraquat.

    Science.gov (United States)

    Nasir, Tauqir; Herzog, Grégoire; Hébrant, Marc; Despas, Christelle; Liu, Liang; Walcarius, Alain

    2018-01-30

    An electrochemical method was developed for rapid and sensitive detection of the herbicide paraquat in aqueous samples using mesoporous silica thin film modified glassy carbon electrodes (GCE). Vertically aligned mesoporous silica thin films were deposited onto GCE by electrochemically assisted self-assembly (EASA). Cyclic voltammetry revealed effective response to the cationic analyte (while rejecting anions) thanks to the charge selectivity exhibited by the negatively charged mesoporous channels. Square wave voltametry (SWV) was then used to detect paraquat via its one electron reduction process. Influence of various experimental parameters (i.e., pH, electrolyte concentration, and nature of electrolyte anions) on sensitivity was investigated and discussed with respect to the mesopore characteristics and accumulation efficiency, pointing out the key role of charge distribution in such confined spaces on these processes. Calibration plots for paraquat concentration ranging from 10 nM to 10 μM were constructed at mesoporous silica modified GCE which were linear with increasing paraquat concentration, showing dramatically enhanced sensitivity (almost 30 times) as compared to nonmodified electrodes. Finally, real samples from Meuse River (France) spiked with paraquat, without any pretreatment (except filtration), were analyzed by SWV, revealing the possible detection of paraquat at very low concentration (10-50 nM). Limit of detection (LOD) calculated from real sample analysis was found to be 12 nM, which is well below the permissible limits of paraquat in drinking water (40-400 nM) in various countries.

  6. A new method to prevent degradation of lithium-oxygen batteries: reduction of superoxide by viologen.

    Science.gov (United States)

    Yang, L; Frith, J T; Garcia-Araez, N; Owen, J R

    2015-01-31

    Lithium-oxygen battery development is hampered by degradation reactions initiated by superoxide, which is formed in the pathway of oxygen reduction to peroxide. This work demonstrates that the superoxide lifetime is drastically decreased upon addition of ethyl viologen, which catalyses the reduction of superoxide to peroxide.

  7. Toxicological effects of paraquat on the histology of the stomach ...

    African Journals Online (AJOL)

    lethal dose that gave 100% death) for Paraquat was obtained as 1g/kg body ... Results: Histopathological examination of the organs studied revealed that the stomach had mild mucosal ulceration, muscular coat atrophy, stromal oedema and ...

  8. Surfactant therapy restores gas exchange in lung injury due to paraquat intoxication in rats

    NARCIS (Netherlands)

    K.L. So; E. de Buijzer; D.A.M.P.J. Gommers (Diederik); U. Kaisers; P.J.J. van Genderen (Perry); B.F. Lachmann (Burkhard)

    1998-01-01

    textabstractParaquat is a weed killer which causes often fatal lung damage in humans and other animals. There is evidence that the pulmonary surfactant system is involved in the pathophysiology of respiratory failure after paraquat intoxication and, therefore, the

  9. 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,

  10. Evidence of bovine serum albumin-viologen herbicide binding interaction and associated structural modifications

    Science.gov (United States)

    Roy, Swarup; Saxena, Shailendra K.; Mishra, Suryakant; Yogi, Priyanka; Sagdeo, P. R.; Kumar, Rajesh

    2017-07-01

    The binding ability of viologen herbicide with bovine serum albumin (BSA) has been investigated to understand viologen associated hazards by investigating ethyl viologen's (EV) binding using various spectroscopies and in-silico molecular docking approaches. Apparent association constant (1.3 × 104 L/mol), calculated using UV-Vis spectra indicating a moderate complex formation between BSA and EV. A static mode of fluorescence quenching has been observed as evident from inverse temperature dependence of Stern-Volmer quenching constant which also confirms an EV-BSA complex formation. Emission and time resolved fluorescence studies reveal that the emission quenching of BSA with EV is initiated by static quenching mechanism. A moderately strong binding affinity between EV and BSA has been observed (binding constant value of 7.58 × 104 L/Mol) using fluorescence quenching titration, obtained at 298 K. Quantitative measurements of thermodynamic parameters like enthalpy and entropy changes clearly indicates hydrophobic force responsible for EV-BSA complex formation. The binding distance between EV and BSA was found to be 4.48 nm are involved in non-radiative energy transfer process. Furthermore, from the circular dichroism spectra it was observed that addition of EV is also found to change the secondary structure of BSA which leads to decrease in α-helix. Above mentioned results are found to be in consonance with molecular docking simulations and supports the EV-BSA binding.

  11. In vitro PAMAM, phosphorus and viologen-phosphorus dendrimers prevent rotenone-induced cell damage.

    Science.gov (United States)

    Milowska, Katarzyna; Szwed, Aleksandra; Zablocka, Maria; Caminade, Anne-Marie; Majoral, Jean-Pierre; Mignani, Serge; Gabryelak, Teresa; Bryszewska, Maria

    2014-10-20

    We have investigated whether polyamidoamine (PAMAM), phosphorus (pd) and viologen-phosphorus (vpd) dendrimers can prevent damage to embryonic mouse hippocampal cells (mHippoE-18) caused by rotenone, which is used as a pesticide, insecticide, and as a nonselective piscicide, that works by interfering with the electron transport chain in mitochondria. Several basic aspects, such as cell viability, production of reactive oxygen species and changes in mitochondrial transmembrane potential, were analyzed. mHippoE-18 cells were treated with these structurally different dendrimers at 0.1μM. A 1h incubation with dendrimers was followed by the addition of rotenone at 1μM, and a further 24h incubation. PAMAM, phosphorus and viologen-phosphorus dendrimers all increased cell viability (reduced cell death-data need to be compared with untreated controls). A lower level of reactive oxygen species and a favorable effect on mitochondrial system were found with PAMAM and viologen-phosphorus dendrimers. These results indicate reduced toxicity in the presence of dendrimers. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Impact of Backbone Tether Length and Structure on the Electrochemical Performance of Viologen Redox Active Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Burgess, Mark; Chénard, Etienne; Hernández-Burgos, Kenneth; Nagarjuna, Gavvalapalli; Assary, Rajeev S.; Hui, Jingshu; Moore, Jeffrey S.; Rodríguez-López, Joaquín

    2016-10-25

    The design of chemically stable and electrochemically reversible redox active polymers (RAPs) is of great interest for energy storage technologies. Particularly, RAPs are new players for flow batteries relying on a size-exclusion based mechanism of electrolyte separation, but few studies have provided detailed molecular understanding of redox polymers in solution. Here, we use a systematic molecular design approach to investigate the impact of linker and redox-pendant electronic interactions on the performance of viologen RAPs. We used scanning electrochemical microscopy, cyclic voltammetry, bulk electrolysis, temperature-dependent absorbance, and spectroelectrochemistry to study the redox properties, charge transfer kinetics, and self-exchange of electrons through redox active dimers and their equivalent polymers. Stark contrast was observed between the electrochemical properties of viologen dimers and their corresponding polymers. Electron self-exchange kinetics in redox active dimers that only differ by their tether length and rigidity influences their charge transfer properties. Predictions from the Marcus Hush theory were consistent with observations in redox active dimers, but they failed to fully capture the behavior of macromolecular systems. For example, polymer bound viologen pendants, if too close in proximity, do not retain chemical reversibility. In contrast to polymer films, small modifications to the backbone structure decisively impact the bulk electrolysis of polymer solutions. This first comprehensive study highlights the careful balance between electronic interactions and backbone rigidity required to design RAPs with superior electrochemical performance.

  13. 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)

  14. Genotoxic effects of glyphosate or paraquat on earthworm coelomocytes.

    Science.gov (United States)

    Muangphra, Ptumporn; Kwankua, Wimon; Gooneratne, Ravi

    2014-06-01

    The potential genotoxicity (nuclear anomalies, damage to single-strand DNA) and pinocytic adherence activity of two (glyphosate-based and paraquat-based) commercial herbicides to earthworm coelomocytes (immune cells in the coelomic cavity) were assessed. Coelomocytes were extracted from earthworms (Pheretima peguana) exposed to concentrations earthworms exposed to glyphosate at 25 × 10(-1) (10(-3) LC50) and paraquat at 39 × 10(-5) (10(-4) LC50) μg cm(-2) filter paper. In earthworms exposed to glyphosate, no differences in tail DNA%, tail length, and tail moment of coelomocytes were detected. In contrast, for paraquat at 10(-1) LC50 concentration, there were significant (P earthworm coelomocytes whereas glyphosate causes only aneugenic effects and therefore does not pose a risk of gene mutation in this earthworm. Copyright © 2012 Wiley Periodicals, Inc.

  15. Ultrastructure of paraquat-treated slash pine (Pinus elliottii engelm. )

    Energy Technology Data Exchange (ETDEWEB)

    Birchem, R.; Brown, C.L.

    1979-01-01

    The introduction of paraquat into the transpiration stream of young slash pine trees significantly enhances oleoresin biogenesis and results in localized resin soaking in treated portions of the bole. All affected cells of the xylem symplast, including those not directly assocated with resin ducts, begin to synthesize excessive oleoresin and secret or lose it initially through pits into the lumen of contiguous tracheids. Oleoresin is observed in plastids, mitochondrial envelopes, vacuoles, and ER cisternae in both control and treated trees. Cells near the site of paraquat treatment show extreme damage to membrane integrity, depletion of starch, and loss of cellular organization.

  16. The toxicological effect of paraquat post emergence herbicide on ...

    African Journals Online (AJOL)

    The results showed that there were significant differences (P< 0.05) in vegetative growth in cowpea plants when paraquat was used as post emergence herbicide for weed control. There was good growth and adequate weed control achieved by all herbicide treatments evaluated until 9 weeks after planting (WAP) before ...

  17. Anion effects on the cyclobis(paraquat-p-phenylene) host

    DEFF Research Database (Denmark)

    Andersen, Sissel Stenbæk; Jensen, Morten; Sørensen, Anne

    2012-01-01

    Binding studies between the electron accepting host cyclobis(paraquat-p-phenylene) and a series of electron donors in the presence of differently sized counteranions reveal that both the nature and the concentration of the anion have a large impact on the association strength of the resulting host...

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

    African Journals Online (AJOL)

    Erah

    Purpose: The present study was conducted to determine the effect of vitamins C and E administration on the outcome of therapy in patients with paraquat intoxication admitted in the Poisoning Emergency. Department (PED) of Noor Teaching General Hospital, Isfahan, Iran. Methods: We studied retrospectively medical ...

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

    African Journals Online (AJOL)

    We report a fatal case of a16 year old girl who presented with dysphagia, cough and dyspnoea following ingestion of paraquat. She subsequently developed acute kidney injury (AKI) that resolved but she succumbed to respiratory complications despite use of antibiotics, corticosteroids and haemodialysis. Key words: ...

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

    African Journals Online (AJOL)

    event were found to have interstitial pulmonary fibrosis with decreased lung capacity. In the same study,[7] patients who developed pneumomediastinum within 7 days all died. Some of these patients had pneumothoraces. The mortality rate for patients who had used paraquat in a suicide attempt was 96% (26/27), while that ...

  1. Translocation of radioactive paraquat in some veld grasses | TD ...

    African Journals Online (AJOL)

    In two pot experiments radioactive paraquat was applied to certain important veld grasses (Experiment I-Aristida junciformis, Themeda triandra, Elyonuris argenteus, Andropogon filifolius, Eragrostis curvula; Experiment II-A. junciformis, E. argenteus) to determine the extent of translocation at a young stage of growth with ...

  2. Histopathological changes induced by paraquat on some tissues of ...

    African Journals Online (AJOL)

    The liver showed hypotrophy of liver cells, cloudy swelling and formation of cytoplasmic vacuoles in the liver tissue of fish treated with 0.15 and 0.3 mg/l concentrations of paraquat. Disorder in the ellipsoid cell and hemosiderin accumulation in melano-macrophage centers was observed in the spleen tissue of fish exposed ...

  3. Spatially resolved Raman spectroelectrochemistry of solid-state polythiophene/viologen memory devices.

    Science.gov (United States)

    Kumar, Rajesh; Pillai, Rajesh G; Pekas, Nikola; Wu, Yiliang; McCreery, Richard L

    2012-09-12

    A three terminal molecular memory device was monitored with in situ Raman spectroscopy during bias-induced switching between two metastable states having different conductivity. The device structure is similar to that of a polythiophene field effect transistor, but ethylviologen perchlorate was added to provide a redox counter-reaction to accompany polythiophene redox reactions. The conductivity of the polythiophene layer was reversibly switched between high and low conductance states with a "write/erase" (W/E) bias, while a separate readout circuit monitored the polymer conductance. Raman spectroscopy revealed reversible polythiophene oxidation to its polaron form accompanied by a one-electron viologen reduction. "Write", "read", and "erase" operations were repeatable, with only minor degradation of response after 200 W/E cycles. The devices exhibited switching immediately after fabrication and did not require an "electroforming" step required in many types of memory devices. Spatially resolved Raman spectroscopy revealed polaron formation throughout the polymer layer, even away from the electrodes in the channel and drain regions, indicating that thiophene oxidation "propagates" by growth of the conducting polaron form away from the source electrode. The results definitively demonstrate concurrent redox reactions of both polythiophene and viologen in solid-state devices and correlate such reactions with device conductivity. The mechanism deduced from spectroscopic and electronic monitoring should guide significant improvements in memory performance.

  4. 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.

  5. Silvichemicals and fuels from Paraquat: treated pine trees

    Energy Technology Data Exchange (ETDEWEB)

    Bungay, H.R.; Ward, R.W.

    1976-01-01

    Various aspects of the conversion of biomass to fuels and chemical feedstocks are discussed. It is pointed out that pine trees become a more attractive biomass source, if the fast growth rate of certain species is considered. In addition a three-fold increase in oleoresin formation has been observed when the trees are treated with paraquat during cultivation, thus making the silvichemicals produced more economical. (JGB)

  6. Voltammetric Quantification of Paraquat and Glyphosate in Surface Waters

    Directory of Open Access Journals (Sweden)

    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.

  7. 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

    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. 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. 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 standard deviation (RSD) was

  8. 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

  9. Size changes in honey bee larvae oenocytes induced by exposure to Paraquat at very low concentrations.

    Directory of Open Access Journals (Sweden)

    Marianne Cousin

    Full Text Available The effects of the herbicide Paraquat were investigated in honey bee larvae with attention focused on oenocytes. Honey bee larvae were exposed to Paraquat at different concentrations in the food: 0, 0.001, 0.01, 0.1 and 1 µg/kg. In controls, between 24 h and 48 h, oenocytes grew from 630.1 to 1643.8 µm(2 while nuclei changed in size from 124.9 to 245.6 µm(2. At 24 h, Paraquat induced a slight decrease in the size of oenocytes and nuclei. N-acetylcysteine (NAC, an antioxidant substance, slightly lowered the effects of Paraquat. At 48 h, Paraquat elicited a strong concentration-dependent decrease in the size of oenocytes, even at the lowest concentration. NAC reversed the effect of Paraquat at a concentration of ≥0.01 µg/kg. This reversion suggested different modes of action of Paraquat, with an oxidant action prevalent at concentrations ≥0.01 µg/kg. This study is the first which reports an effect of a pesticide at the very low concentration of 1 ng/kg, a concentration below the detection limits of the most efficient analytic methods. It shows that chemicals, including pesticides, are likely to have a potential impact at such exposure levels. We also suggest that Paraquat could be used as a suitable tool for investigating the functions of oenocytes.

  10. 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.)

  11. 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.

  12. Effect of paraquat as post emergence herbicide on yield of cowpea ...

    African Journals Online (AJOL)

    The experiment reported herein was undertaken to determine the toxicological effect of paraquat as post emergence herbicide on yield of cowpea. Two rates of paraquat 0.50 kg ai/ha and 1.00kg ai/ha were applied as post emergence herbicide in pot experiment with fallow weed population; which examined the ...

  13. 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.

  14. The respiratory molybdo-selenoprotein formate dehydrogenases of Escherichia coli have hydrogen: benzyl viologen oxidoreductase activity

    Directory of Open Access Journals (Sweden)

    Trchounian Armen

    2011-08-01

    Full Text Available Abstract Background Escherichia coli synthesizes three membrane-bound molybdenum- and selenocysteine-containing formate dehydrogenases, as well as up to four membrane-bound [NiFe]-hydrogenases. Two of the formate dehydrogenases (Fdh-N and Fdh-O and two of the hydrogenases (Hyd-1 and Hyd-2 have their respective catalytic subunits located in the periplasm and these enzymes have been shown previously to oxidize formate and hydrogen, respectively, and thus function in energy metabolism. Mutants unable to synthesize the [NiFe]-hydrogenases retain a H2: benzyl viologen oxidoreductase activity. The aim of this study was to identify the enzyme or enzymes responsible for this activity. Results Here we report the identification of a new H2: benzyl viologen oxidoreductase enzyme activity in E. coli that is independent of the [NiFe]-hydrogenases. This enzyme activity was originally identified after non-denaturing polyacrylamide gel electrophoresis and visualization of hydrogen-oxidizing activity by specific staining. Analysis of a crude extract derived from a variety of E. coli mutants unable to synthesize any [NiFe]-hydrogenase-associated enzyme activity revealed that the mutants retained this specific hydrogen-oxidizing activity. Enrichment of this enzyme activity from solubilised membrane fractions of the hydrogenase-negative mutant FTD147 by ion-exchange, hydrophobic interaction and size-exclusion chromatographies followed by mass spectrometric analysis identified the enzymes Fdh-N and Fdh-O. Analysis of defined mutants devoid of selenocysteine biosynthetic capacity or carrying deletions in the genes encoding the catalytic subunits of Fdh-N and Fdh-O demonstrated that both enzymes catalyze hydrogen activation. Fdh-N and Fdh-O can also transfer the electrons derived from oxidation of hydrogen to other redox dyes. Conclusions The related respiratory molybdo-selenoproteins Fdh-N and Fdh-O of Escherichia coli have hydrogen-oxidizing activity. These findings

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

    Science.gov (United States)

    Rudyk, Chris; Litteljohn, Darcy; Syed, Shuaib; Dwyer, Zach; Hayley, Shawn

    2015-01-01

    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.

  16. Uptake and transport of paraquat in slash pine. [/sup 14/C tracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Brown, C.L.; Nix, L.E.

    1975-12-01

    Uptake and movement of paraquat (1,1'dimethyl-4,4'bipyridylium dichloride into the transpiration stream of 25-year-old slash pine (Pinus elliottii Engelm.) trees was followed using methyl-/sup 14/C-paraquat (10..mu..Ci/tree) applied in 8 and 3 percent solutions with commercial paraquat. Initial uptake from saturated cellulose pads into xylem was rapid, whereas upward axial movement in outer rings of xylem was 100-fold less than the established velocity of water transport in pines. Velocity of paraquat-/sup 14/C movement was approximately 30 cm/day vertically and 0.5 cm/day radially along negative pressure gradients in xylem. Recovery of /sup 14/C-paraquat by sulphuric acid extraction of xylem samples above the site of application, followed by thin layer chromatography of partially purified extracts, indicated that much radioactivity was still in the form of methyl-/sup 14/C-paraquat. The physiological significance of paraquat's strong affinity for cellulose, resulting in its slow movement both vertically and horizontally, is briefly discussed as it relates to increased oleoresin synthesis and lightwood formation.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Competitive adsorption of viologen species on a chloride modified copper (100) surface

    Energy Technology Data Exchange (ETDEWEB)

    Saracino, Martino; Wandelt, Klaus [Institut of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115 Bonn (Germany); Hai, Nguyen Thi Minh; Broekmann, Peter [Interfacial Electrochemistry Group, Department of Chemistry and Biochemistry, University of Berne (Switzerland)

    2010-07-01

    A number of technological relevant processes involve charge transfer reactions at electrified solid/liquid-interfaces. Their microscopic understanding requires the study of the electrode surface under in situ reactive conditions, for instance STM and cyclic voltammetry. The competitive adsorption of Diphenyl- (DPV) and Dibenzylviologen (DBV) on a Cl{sup -} modified Cu(100) surface was chosen as model system for similar N-containing aromatic molecules, which play a significant role as additives in metal plating. Upon adsorption DPV{sup 2+} is reduced even at most anodic potentials to the monocationic radical DPV{sup +*} and forms a full monolayer of a hydrophobic {pi}-stacked stripe phase which, however, does not prevent further redox reactions to take place. Lowering the electrode potential to the DBV{sup 2+} reduction potential at -250 mV[RHE] leads to the replacement of the DPV{sup +*} phase by a {pi}-stacked stripe phase consisting of the produced monocationic DBV{sup +*}. Conversely, returning to the DPV{sup +*} oxidation potential at -100 mV[RHE] leads to a re-substitution of the DBV{sup +*}- by the initial DPV{sup +*}-stripe phase. In contrast to mono-viologen systems no stable dicationic phases have been observed at all.

  20. High Performance Poly(viologen)-Graphene Nanocomposite Battery Materials with Puff Paste Architecture.

    Science.gov (United States)

    Beladi-Mousavi, Seyyed Mohsen; Sadaf, Shamaila; Mahmood, Arsalan Mado; Walder, Lorenz

    2017-09-26

    Four linear poly(viologens) (PV1, PV2: phenylic, PV3: benzylic, and PV4: aliphatic) in tight molecular contact with reduced graphene oxide (rGO), that is, PV@rGO, were prepared and used as anodic battery materials. These composites show exceptionally high, areal, volumetric, and current densities, for example, PV1@rGO composites (with 15 wt % rGO, corresponding to 137 mAh g-1) show 13.3 mAh cm-2 at 460 μm and 288 mAh cm-3 with 98% Coulombic efficiency at current densities up to 1000 A g-1, better than any reported organic materials. These remarkable performances are based on (i) molecular self-assembling of PVs on individual GO sheets yielding colloidal PV@GO and (ii) efficient GO/rGO transformation electrocatalyzed by PVs. Ion breathing during charging/discharging was studied by electrochemical quartz crystal microbalance and electrochemical atomic force microscopy revealing an absolute reversible and strongly anisotropic thickness oscillation of PV1@rGO at a right angle to the macroscopic current collector. It is proposed that such stress-free breathing is the key property for good cyclability of the battery material. The anisotropy is related to a puff paste architecture of rGO sheets parallel to the macroscopic current collector. A thin graphite sheet electrode with an areal capacity of 1.23 mAh cm-2 is stable over 200 bending cycles, making the material applicable for wearable electronics. The polymer acts as a lubricant between the rGO layers if shearing forces are active.

  1. 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.

  2. 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.

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

    OpenAIRE

    Chester, G.; Woollen, B. H.

    1982-01-01

    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 knap...

  4. Inhibitory effects of paraquat on photosynthesis and the response to oxidative stress in Chlorella vulgaris.

    Science.gov (United States)

    Qian, Haifeng; Chen, Wei; Sun, Liwei; Jin, Yuanxiang; Liu, Weiping; Fu, Zhengwei

    2009-07-01

    This study investigated the effects of paraquat, a widely used herbicide, on the aquatic unicellular alga Chlorella vulgaris through short-term toxicity tests at the physiological and gene transcriptional levels. Exposure to 0.5 microM paraquat increased the activities of the antioxidant enzymes superoxide dismutase, peroxidase, and catalase to levels 4.93, 3.19, and 3.09 times higher, respectively, than those of the control. Furthermore, exposure to 0.75 microM paraquat increased the activities of these antioxidant enzymes to even higher levels. The decrease in chlorophyll content and the increases in reactive oxygen species (ROS) and malondialdehyde content following exposure to paraquat suggest that the alga was severely damaged and cell growth was greatly inhibited. Real-time PCR showed that paraquat reduced the transcript abundance of psaB and rbcL to 7.09 and 29.83% of the control, respectively. Our results demonstrate that paraquat inhibited electron transport and CO2 assimilation, and also triggered the synthesis of ROS that disrupt cellular structure and inhibit cell growth.

  5. Protective effect of ambroxol against paraquat-induced pulmonary fibrosis in rats.

    Science.gov (United States)

    Zhi, Qiao-Ming; Yang, Li-Tao; Sun, Hai-chen

    2011-01-01

    To evaluate the possible therapeutic effect of ambroxol on pulmonary fibrosis induced by paraquat. Adult male Sprague-Dawley rats (n=144, 200-250 g) were divided into four groups (Control, Ambroxol, Paraquat, and Paraquat+Ambroxol group) and sacrificed on day 1, 3, 5, 7, 14 and 28. Several significant oxidant stress markers (MDA, SOD and GSH-PX), MPO activity, cytokines (TNF-α, MCP-1, TGF-β1, MMP-2 and TIMP-1), total inflammatory cell count, hydroxyproline content, collagen I and III mRNA were analyzed. In Paraquat group, the MDA, MPO activity, hydroxyproline contents, the mRNA expression of TNF-α, MCP-1, TGF-β1, MMP-2, TIMP-1, collagen I, collagen III and the number of total inflammatory cells were up-regulated in lung tissue, but SOD and GSH-PX activity were down-regulated in lung tissue compared with Control group (pambroxol group, the MDA, MPO activity, hydroxyproline content, the mRNA expression of TNF-α, MCP-1, TGF-β1, MMP-2, TIMP-1 collagen I, collagen III and the number of total inflammatory cells were significantly decreased, while the SOD and GSH-PX activities in lung tissue were increased compared with Paraquat group (pAmbroxol could markedly reduce such damage in lung tissue and prevent pulmonary fibrosis. The results of this study indicated that ambroxol could reduce lung damage and prevent pulmonary fibrosis induced by paraquat.

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

    Science.gov (United States)

    Williams, June H; Whitehead, Zandri; Van Wilpe, Erna

    2016-11-09

    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.

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

    Directory of Open Access Journals (Sweden)

    June H. Williams

    2016-02-01

    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.

  8. Effect of salinity on adsorption and desorption of paraquat in Pak Phanang river sediment, Thailand.

    Science.gov (United States)

    Noicharoen, Damrongsak; Parkpian, Preeda; Shipin, Oleg V; Polprasert, Chongrak; Delaune, Ronald D; Kongchum, Manoch

    2012-01-01

    Batch experiments were conducted to study the effect of salinity (0-30 g L(-1)) on adsorption and desorption of paraquat (1, 1'-dimethyl-4, 4'-dipyridylium dichloride), one of the most widely used herbicides in the world, in sediment of Pak Phanang River Basin, Thailand. Sediments from five locations were used in the studies (two from freshwater sites and three sites under saline environment). The adsorption capacity (K(f)) of the sediments was positively correlated with CEC (r = 0.81**) and clay content (r = 0.70*). Paraquat adsorption by sediment was faster under fresh water (0 g L(-1)) versus saline conditions (10 and 20 g L(-1)). The adsorption coefficient (K(f)) at low salinity (0 g L(-1)) was 17,302 whereas the K(f) at 10 and 20 g L(-1) were 5,344 and 4,263, respectively. Paraquat desorption was greater at higher salinity, which is similar to the salinity of estuarine or seawater. Approximately 12-31 % of sorbed paraquat in fresh water and saline sediment (7.67 and 7.98 mg kg(-1)) were released when leaching with 20 g L(-1) salinity. The amount of paraquat released was in proportion to the amount sorbed. Results show that increases in salinity resulting from salt water intrusion from the lower estuary into the Pak Phanang River Basin would result in release of adsorbed paraquat from sediment into the water column.

  9. Generating power from cellulose in an alkaline fuel cell enhanced by methyl viologen as an electron-transfer catalyst

    Science.gov (United States)

    Hao, Miaoqing; Liu, Xianhua; Feng, Mengnan; Zhang, Pingping; Wang, Guangyi

    2014-04-01

    In this work, we developed a single-compartment direct cellulose alkaline fuel cell by using nickel foam as the anode and methyl viologen as an electron transfer catalyst. The maximum power density of the fuel cell at optimal conditions is 450 mW m-2. High-performance liquid chromatography detected short-chain aliphatic carboxylic acids in the oxidation products. Using common reed and red algae as fuels, the fuel cell achieved maximum power densities of 295 mW m-2 and 154 mW m-2, respectively.

  10. Inclusion complex of α-cyclodextrin and the extended viologen dication: a model of an insulated molecular wire

    Czech Academy of Sciences Publication Activity Database

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

    2011-01-01

    Roč. 70, 3-4 (2011), s. 461-469 ISSN 0923-0750 R&D Projects: GA MŠk(CZ) MEB041006; GA MŠk LC510; GA MŠk OC 140; GA ČR GA203/08/1157; GA ČR GA203/09/1607; GA AV ČR IAA400400802 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40550506 Keywords : alpha- cyclodextrin * extended viologen * complex formation Subject RIV: CG - Electrochemistry Impact factor: 1.886, year: 2011

  11. Paraquat and Parkinson's disease: a systematic review protocol according to the OHAT approach for hazard identification.

    Science.gov (United States)

    Vaccari, Carolina; El Dib, Regina; de Camargo, João Lauro V

    2017-05-15

    Parkinson's disease (PD) is a progressive neurodegenerative condition that has genetic susceptibility, aging, and exposure to certain chemicals as risk factors. In recent decades, epidemiological and experimental studies have investigated the role of pesticides in the development of PD, in particular that of the herbicide paraquat. Here, we, therefore, aim to systematically review the association between paraquat exposure and PD. Observational studies (cohort, case-control, and cross-sectional) eligible for this systematic review will enroll any participant who was occupationally and/or environmentally exposed to paraquat. Experimental studies, including in vivo and in vitro assays designed to assess neurotoxicological endpoints or mechanisms of paraquat neurotoxicity, will also be eligible. Outcomes of interest include the following: PD diagnosis; neurobehavioral, biochemical, and/or morphological alterations; and cellular, biochemical, and/or molecular pathways to oxidative stress. Using terms to include all forms of paraquat combined with PD, the following electronic databases will be searched: PubMed, EMBASE, LILACS, Toxnet, and Web of Science, without restrictions as to language, year, or status of publication. A team of reviewers will independently select potential titles and abstracts, extract data, assess risk of bias, and determine the overall quality of evidence for each outcome using the Office of Health Assessment and Translation (OHAT) approach for systematic reviews and evidence integration. Dichotomous data will be summarized as odds ratios, and continuous data will be given as mean differences, both with their respective 95% confidence intervals. This is the first time that the OHAT systematic review protocol will be applied to investigate a possible causal association between exposure to paraquat and PD. Results from this study could serve as basis for regulatory agencies to define paraquat levels of concern, supporting its risk assessment process

  12. APACHE score, Severity Index of Paraquat Poisoning, and serum lactic acid concentration in the prognosis of paraquat poisoning of Chinese Patients.

    Science.gov (United States)

    Xu, Shuyun; Hu, Hai; Jiang, Zhen; Tang, Shiyuan; Zhou, Yuangao; Sheng, Jie; Chen, Jinggang; Cao, Yu

    2015-02-01

    Many prognostic indictors have been studied to evaluate the prognosis of paraquat poisoning. However, the optimal indicator remains unclear. To determine the value of the Acute Physiology and Chronic Health Evaluation II (APACHE II) score, the Severity Index of Paraquat Poisoning (SIPP), and serum lactate levels in the prognosis of paraquat poisoning, we performed a prospective study that enrolled 143 paraquat patients. Data were collected from patients (161) at West China Hospital in Chengdu, China, including details about the patients' general conditions, laboratory examinations, and treatment. Receiver operating characteristic curves for predicting inpatient mortality based on APACHE II score, SIPP, and lactate levels were generated. To analyze the best cutoff values for lactate levels, APACHE II scores, and SIPP in predicting the prognosis of paraquat poisoning, the initial parameters on admission and 7-day survival curves of patients with lactate levels greater than or equal to 2.95 mmol/L, APACHE II score greater than or equal to 15.22, and SIPP greater than or equal to 5.50 h · mg/L at the time of arrival at West China Hospital were compared using the 1-way analysis of variance and the log-rank test. The APACHE II score (5.45 [3.67] vs 11.29 [4.31]), SIPP (2.78 [1.89] vs 7.63 [2.46] h · mg/L), and lactate level (2.78 [1.89] vs 7.63 [2.46] mmol/L) were significantly lower in survivors (77) after oral ingestion of paraquat, compared with nonsurvivors (66). The APACHE II score, SIPP, and lactate level had different areas under the curve (0.847, 0.789, and 0.916, respectively) and accuracy (0.64, 0.84, and 0.89, respectively). Respiratory rate, serum creatinine level, Paco2, and mortality rate at 7 days after admission in patients with lactate levels greater than or equal to 2.95 mmol/L were markedly different compared with those of other patients (P APACHE II score and SIPP for acute oral paraquat poisoning.

  13. Paraquat Toxicity on Root Nodule Formation on Macroptiliuma tropurpureum Urb. and Its Corelation with Population of Rhizobium sp.

    Directory of Open Access Journals (Sweden)

    Erni Martani

    2004-12-01

    Full Text Available This study was designed to investigate the paraquat toxicity toward root nodulation by Rhizobium on Macroptilium atropurpureum as an indicator plant. The legume was grown in Thornton medium treated with several concentrations of paraquat and inoculated with R.japonicum 143 (Rj-143 or Rhizobium sp. C-1.1. These bacteria represent cross-inoculation of soybean and cover-crops legumes, respectively. Nodule formation and Rhizobium population were measured periodically. At the end of planting time, nitrogenase activity of the nodules was analysis based on ARA (Acethylene Reduction Analysis method. The results showed that nodules in plants inoculated with Rhizobium without addition paraquat, were formed within four weeks. There was no nodulation when paraquat was added. Paraquat was toxic to the plant, causing chlorosis, stunting, drying of the plant tissues, and death. The symptoms were detected at the second week after planting time. Paraquat also decreased Rhizobium population from 10^6 to 10^2 or 10^1 CFU/mL at 40 and 100 pp, respectively. These results depicted that paraquat disturbed the plant before nodulation, and at the same time Rhizobium populatin decreased until below minimal population required for nodulation. Therefore, the process of nodulation was disturbed, and in some treatments there was nodulation. It was concluded that paraquat was toxic to both plant and the Rhizobium, which cause nodulation failure.

  14. Paraquat-loaded alginate/chitosan nanoparticles: preparation, characterization and soil sorption studies.

    Science.gov (United States)

    Silva, Mariana dos Santos; Cocenza, Daniela Sgarbi; Grillo, Renato; de Melo, Nathalie Ferreira Silva; Tonello, Paulo Sérgio; de Oliveira, Luciana Camargo; Cassimiro, Douglas Lopes; Rosa, André Henrique; Fraceto, Leonardo Fernandes

    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. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. 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

  16. Physiological effects of paraquat in juvenile African catfish Clarias gariepinus (Burchel 1822

    Directory of Open Access Journals (Sweden)

    Christopher Didigwu Nwani

    2015-01-01

    Full Text Available Objective: To investigate the physiological effects of paraquat in African freshwater catfish Clarias gariepinus. Methods: Two sublethal test concentrations of paraquat (1.37 and 2.75 mg/L were chosen based on the 96 h LC50 value (27.46 mg/L. Some experimental fish were exposed to these concentrations and control group for 15 d. Peripheral blood samplings were taken at intervals for assessment of haematological and biochemical parameters. Results: Exposure to paraquat affected behaviour and morphology of Clarias gariepinus. There were significant decreases (P<0.05 in the mean values of hemoglobin, red blood cells, packed cell volume, cellular hemoglobin, and cellular hemoglobin concentration. The levels of white blood cells, glucose, aspartate aminotransferase, and alanine aminotransferase significantly increased (P<0.05 while protein levels declined. However, no definite pattern of changes was observed in the number and type of leucocytes. Conclusions: The results of the present study indicate that paraquat is toxic and has the potential to impair on the physiological activities in African catfish Clarias gariepinus. The use of paraquat should be strongly controlled and carefully monitored to avoid the possible damage done to the environment.

  17. Adsorption of Paraquat Dichloride by Graphitic Carbon Nitride Synthesized from Melamine Scraps

    Science.gov (United States)

    Watcharenwong, A.; Kaeokan, A.; Rammaroeng, R.; Upama, P.; Kajitvichyanukul, P.

    2017-07-01

    In this research, graphitic carbon nitride (g-C3N4) was synthesized from useless melamine scraps. Mixture of melamine powder and urea was directly burned in the muffle furnace at 550 °C. Later as-synthesized g-C3N4 was modified with hydrochloric acid. The g-C3N4 powder was characterized by several techniques including X-ray diffraction, scanning electron microscope, and specific surface area analyser. Adsorption of the herbicide paraquat from an aqueous solution to suspended particles of g-C3N4 was investigated, taking into consideration several parameters such as initial concentration of paraquat, initial pH, and dosage of g-C3N4. The results showed that with the same amount of g-C3N4, the increase in the paraquat concentration caused the reduction in the removal efficiency and the higher the amount of g-C3N4, the less residual paraquat remained in the bulk solution. G-C3N4 showed better adsorption behaviour in the basic condition. Finally, Langmuir and Freundlich adsorption isotherms were also evaluated. Paraquat adsorption by g-C3N4 was in accordance with Langmuir more than Freundlich adsorption isotherm.

  18. 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.

  19. [Ligninolytic enzyme production by white rot fungi during paraquat (herbicide) degradation].

    Science.gov (United States)

    Camacho-Morales, Reyna L; Gerardo-Gerardo, José Luis; Guillén Navarro, Karina; Sánchez, José E

    Paraquat is a widely used herbicide in agriculture. Its inappropriate use and wide distribution represents a serious pollution problem for soil and water. White rot fungi are capable of degrading pollutants having a similar structure to that of lignin, such as paraquat. This study evaluated the degradation effect of paraquat on the production of ligninolytic enzymes by white rot fungi isolated from the South of Mexico. Six fungal strains showed tolerance to the herbicide in solid culture. Three of the six evaluated strains showed levels of degradation of 32, 26 and 47% (Polyporus tricholoma, Cilindrobasidium laeve and Deconica citrispora, respectively) after twelve days of cultivation in the presence of the xenobiotic. An increase in laccase and manganese peroxidase (MnP) activities was detected in the strains showing the highest percentage of degradation. Experiments were done with enzyme extracts from the extracellular medium with the two strains showing more degradation potential and enzyme production. After 24hours of incubation, a degradation of 49% of the initial paraquat concentration was observed for D. citrispora. These results suggest that paraquat degradation can be attributed to the presence of extracellular enzymes from white rot fungi. In this work the first evidence of the biodegradation potential of D. citrispora and Cilindrobasidium leave is shown. Copyright © 2017 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  20. [Effects of high dose ambroxol on lung injury induced by paraquat in rats].

    Science.gov (United States)

    Ma, Yu-teng; Tian, Ying-ping; Shi, Han-wen; Lv, Cui-huan; Liu, Jian-hui; Sun, Zhi-ping

    2007-09-01

    To evaluate the protective effect of high dose ambroxol, a mucoactive drug, on acute lung injury caused by paraquat in rats. One hundred and thirty-six healthy male Sprague-Dawley rats were randomly divided into three groups: control group (n = 24) injected with normal saline intraperitoneally, PQ group (n = 56) [(2% paraquat (25 mg/kg) injected into peritoneal cavity on the first day)] and AT group (n = 56) ambroxol 35 mg/kg was injected into peritoneum daily after paraquat intoxication once daily for 7 consecutive days. The arterial gas was determined and the extent of lung injury was assessed by measuring the ratio of wet to dry weight (W/D) and protein content in BALF, the WBC count, the percentage of PMN, the content of malondialdehyde (MDA) and the levels of superoxide dismutase (SOD) in the blood and BALF respectively. Left lung tissue was observed through both light microscope and electron microscope (TEM). The white cell count and the content of protein in the blood and the BALF of PQ group were significantly higher than those of the control group (P ambroxol was administered. Treatment with ambroxol (35 mg/kg) could influence the status of oxidative stress in lung and alleviate lung injury induced by paraquat. Ambroxol has obviously therapeutic effect on paraquat poisoning.

  1. Ozone therapy ameliorates paraquat-induced lung injury in rats.

    Science.gov (United States)

    Kaldirim, Umit; Uysal, Bulent; Yuksel, Ramazan; Macit, Enis; Eyi, Yusuf E; Toygar, Mehmet; Tuncer, Salim K; Ardic, Sukru; Arziman, Ibrahim; Aydin, Ibrahim; Oztas, Yesim; Karslioglu, Yildirim; Topal, Turgut

    2014-12-01

    Paraquat (PQ) overdose can cause acute lung injury and death. Ozone therapy (OT) was previously demonstrated to alleviate inflammation and necrosis in various pathologies. We therefore hypothesized that OT has ameliorative and preventive effects on PQ-induced lung damage due to anti-inflammatory and antioxidants properties. Sprague-Dawley rats (n = 24) were separated into three groups: sham, PQ, and PQ+OT groups. 15 mg/kg PQ was administered intraperitoneally in PQ and PQ+OT groups to induce experimental lung injury. One hour after PQ treatment, PQ+OT group was administered a single dose of ozone-oxygen mixture (1 mg/kg/day) by intraperitoneal route for four consecutive days. The animals were sacrificed on fifth day after PQ administration. Blood samples and lung tissues were collected to evaluate the inflammatory processes, antioxidant defense and pulmonary damage. Serum lactate dehydrogenase (LDH) and neopterin levels, tissue oxidative stress parameters, total TGF-β1 levels, and histological injury scores in PQ+OT group were significantly lower than PQ group (Ptherapy. © 2014 by the Society for Experimental Biology and Medicine.

  2. A mechanism of paraquat toxicity involving nitric oxide synthase

    Science.gov (United States)

    Day, Brian J.; Patel, Manisha; Calavetta, Lisa; Chang, Ling-Yi; Stamler, Jonathan S.

    1999-01-01

    Paraquat (PQ) is a well described pneumotoxicant that produces toxicity by redox cycling with cellular diaphorases, thereby elevating intracellular levels of superoxide (O2⨪). NO synthase (NOS) has been shown to participate in PQ-induced lung injury. Current theory holds that NO reacts with O2⨪ generated by PQ to produce the toxin peroxynitrite. We asked whether NOS might alternatively function as a PQ diaphorase and reexamined the question of whether NO/O2⨪ reactions were toxic or protective. Here, we show that: (i) neuronal NOS has PQ diaphorase activity that inversely correlates with NO formation; (ii) PQ-induced endothelial cell toxicity is attenuated by inhibitors of NOS that prevent NADPH oxidation, but is not attenuated by those that do not; (iii) PQ inhibits endothelium-derived, but not NO-induced, relaxations of aortic rings; and (iv) PQ-induced cytotoxicity is potentiated in cytokine-activated macrophages in a manner that correlates with its ability to block NO formation. These data indicate that NOS is a PQ diaphorase and that toxicity of such redox-active compounds involves a loss of NO-related activity. PMID:10535996

  3. Elimination of young erythrocytes from blood circulation and altered erythropoietic patterns during paraquat induced anemic phase in mice.

    Science.gov (United States)

    Bhardwaj, Nitin; Saxena, Rajiv K

    2014-01-01

    Paraquat a widely used herbicide causes a variety of toxic effects on humans and animals. The present study is focused on the interaction of paraquat with the mouse erythroid system. Administration of paraquat (10 mg/kg body weight i.p. on alternate days in C57Bl/6 mice) induced a significant fall in blood erythrocyte count on 7, 14, and 21 day time points but the erythrocyte count reverted back to normal by 28th day indicating the emergence of refractoriness to paraquat. A marked surge in the blood reticulocyte count was observed in paraquat treated mice that also subsided by 28th day. Young erythrocytes in circulation were randomly eliminated from blood circulation in paraquat treated mice and a significant elevation in the level of reactive oxygen species (ROS) was also observed maximally the erythrocytes of this age group. Cells representing various stages of erythroid differentiation in bone marrow and spleen were identified and enumerated flow cytometrically based on their expression of Ter119 and transferrin (CD71) receptor. Proliferative activity of erythroid cells, their relative proportion as well as their absolute numbers fell significantly in bone marrow of paraquat treated mice but all these parameters were significantly elevated in spleens of paraquat treated mice. These changes were essentially restricted to the cells belonging to the two earliest stages of erythroid differentiation. Taken together our results indicate that paraquat treatment causes a transient anemia in mice resulting from random elimination of young circulating erythrocytes as well as depressed erythropoietic activity in bone marrow. Spleen erythropoietic activity however was elevated in paraquat treated mice.

  4. A hybrid soft solar cell based on the mycobacterial porin MspA linked to a sensitizer-viologen Diad.

    Science.gov (United States)

    Perera, Ayomi S; Subbaiyan, Navaneetha K; Kalita, Mausam; Wendel, Sebastian O; Samarakoon, Thilani N; D'Souza, Francis; Bossmann, Stefan H

    2013-05-08

    A prototype of a nano solar cell containing the mycobacterial channel protein MspA has been successfully designed. MspA, an octameric transmembrane channel protein from Mycobacterium smegmatis, is one of the most stable proteins known to date. Eight Ruthenium(II) aminophenanthroline-viologen maleimide Diads (Ru-Diads) have been successfully bound to the MspA mutant MspAA96C via cysteine-maleimide bonds. MspA is known to form double layers in which it acts as nanoscopic surfactant. The nanostructured layer that is formed by (Ru-Diad)8MspA at the TiO2 electrode is photochemically active. The resulting "protein nano solar cell" features an incident photon conversion efficiency of 1% at 400 nm. This can be regarded as a proof-of-principle that stable proteins can be successfully integrated into the design of solar cells.

  5. Traumatic brain injury, paraquat exposure, and their relationship to Parkinson disease.

    Science.gov (United States)

    Lee, Pei-Chen; Bordelon, Yvette; Bronstein, Jeff; Ritz, Beate

    2012-11-13

    Traumatic brain injury (TBI) increased risk of Parkinson disease (PD) in many but not all epidemiologic studies, giving rise to speculations about modifying factors. A recent animal study suggested that the combination of TBI with subthreshold paraquat exposure increases dopaminergic neurodegeneration. The objective of our study was to investigate PD risk due to both TBI and paraquat exposure in humans. From 2001 to 2011, we enrolled 357 incident idiopathic PD cases and 754 population controls in central California. Study participants were asked to report all head injuries with loss of consciousness for >5 minutes. Paraquat exposure was assessed via a validated geographic information system (GIS) based on records of pesticide applications to agricultural crops in California since 1974. This GIS tool assesses ambient pesticide exposure within 500 m of residences and workplaces. In logistic regression analyses, we observed a 2-fold increase in risk of PD for subjects who reported a TBI (adjusted odds ratio [AOR] 2.00, 95% confidence interval [CI] 1.28-3.14) and a weaker association for paraquat exposures (AOR 1.36, 95% CI 1.02-1.81). However, the risk of developing PD was 3-fold higher (AOR 3.01, 95% CI 1.51-6.01) in study participants with a TBI and exposure to paraquat than those exposed to neither risk factor. While TBI and paraquat exposure each increase the risk of PD moderately, exposure to both factors almost tripled PD risk. These environmental factors seem to act together to increase PD risk in a more than additive manner.

  6. Histopathological changes induced by paraquat on some tissues of gourami fish (Trichogaster trichopterus

    Directory of Open Access Journals (Sweden)

    M. Banaee

    2013-03-01

    Full Text Available Paraquat is a contact and non-selective herbicide which is used for controlling a wide range of terrestrial weeds and aquatic plants. A long-term contact with this xenobiotic can potentially lead to injuries in fishes as live non-target organisms. Therefore, the current study aimed to investigate the effect of sub-lethal toxicity of paraquat on the pathology of gill, liver, and spleen tissues in gourami fish (Trichogaster trichopterus. In this study, sub-lethal concentration is determined based on lethal concentration (LC50 : 7.16±0.69, 4.46±0.43, 2.19±0.27 and 1.41±0.17 mg/l of paraquat within 24, 48, 72 and 96 hours, respectively. The experiment was done with four varied concentrations of paraquat (0.0, 0.07, 0.15, and 0.3 mg/l equal 0.0%, 5%, 10% and 20% of nominal value of 96 h LC50 during 3 weeks. The exposed fish displayed erratic swimming and became lethargic. The changes in gills were characterized by hypertrophy, epithelial, epithelium increase of gill filament, edema and secondary gill lamella. The liver showed hypotrophy of liver cells, cloudy swelling and formation of cytoplasmic vacuoles in the liver tissue of fish treated with 0.15 and 0.3 mg/l concentrations of paraquat. Disorder in the ellipsoid cell and hemosiderin accumulation in melano-macrophage centers was observed in the spleen tissue of fish exposed to 0.15 and 0.3 mg/l of paraquat.

  7. 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

  8. Attempt to induce lightwood in balsam fir and tamarack by treating with paraquat

    Energy Technology Data Exchange (ETDEWEB)

    Kiatgrajai, P. (Univ. of Wisconsin, Madison); Conner, A.H.; Rowe, J.W.; Peters, W.; Roberts, D.R.

    1976-07-01

    Treatment of balsam fir (Abies balsamea (L.) Mill.) and tamarack (Larix laricina (Du Roi) K. Koch) with the herbicide paraquat did not induce formation of lightwood. However, a dead zone of phloem extended above the paraquat-treatment site. In balsam fir, the wood directly behind the dead zone was particularly heavily attacked by fungi. In both species, traumatic resin ducts were observed in the last several growth rings of wood adjacent to the treatment site. The ether extract of the tamarack, but not of the balsam fir, was essentially oleoresin.

  9. Ultrastructure of paraquat-treated pine cells (Pinus elliottii Engelm. ) in suspension culture

    Energy Technology Data Exchange (ETDEWEB)

    Birchem, R.; Henk, W.G.; Brown, C.L.

    1979-01-01

    The ultrastructure of liquid suspension cultures of Pinus elliottii was studied, noting characteristics of dividing and senescent cells. The cultures were treated with 0.01, 0.1, 1.0 and 10.0 mg 1/sup -1/ paraquat, an herbicide which stimulates oleoresin synthesis and resinosis in the xylem of treated pine trees. The ultrastructural effects of the toxin were studied at each paraquat concentration over a period of 24 days. The ultrastructural observations are correlated with physiological studies in suspension culture and in living trees.

  10. Effect of paraquat on the incorporation of radiolabelled proline into acid-extractable lung proteins and collagens

    Energy Technology Data Exchange (ETDEWEB)

    Engelbrecht, F.M.; Windt, M.L.; Maree, E.; Nienaber, M.W.P. (Stellenbosch Univ. (South Africa))

    1982-11-06

    In this comparative study we describe the influence of paraquat on the rate of L-2,3-/sup 3/H-proline incorporation into the acid-extractable proteins and into newly synthesized protropocollagen molecules from the lungs of rats and rabbits. Exposure to paraquat took two forms: (a) addition of paraquat in vitro to lung tissue taken from rats and rabbits, and (b) intraperitoneal injection of paraquat prior to death. Paraquat (0,5 - 1,0 mM) added in vitro significantly slowed the rates of /sup 3/H-proline incorporation into the acid-extractable proteins and into newly synthesized protropocoilagen in both rat and rabbit lung tissue. Paraquat administered intraperitoneally (27mg/kg) to rabbits did not markedly influence the rate of /sup 3/H-proline incorporation into acid-extractable proteins and collagen assessed in vitro 24, 48 and 96 hours after injection. Paraquat injected intraperitoneally into rats induced no significant difference in synthesis rates of acid-soluble proteins up to 48 hours after injection. During the same period, the collagen synthesis rate of rat lung tissue was reduced. At 96 hours an increase was found when the rate of synthesis was expressed as cpm/mg DNA and as cpm/..mu..g hydroxyproline.

  11. 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.

  12. Losartan attenuates paraquat-induced pulmonary fibrosis in rats.

    Science.gov (United States)

    Guo, F; Sun, Y B; Su, L; Li, S; Liu, Z F; Li, J; Hu, X T; Li, J

    2015-05-01

    Paraquat (PQ) is one of the most widely used herbicides in the world and can cause pulmonary fibrosis in the cases with intoxication. Losartan, an angiotensin II type 1 receptor antagonist, has beneficial effects on the treatment of fibrosis. The aim of this study was to examine the effect of losartan on pulmonary fibrosis in PQ-intoxicated rats. Adult male Sprague Dawley rats (n = 32, 180-220 g) were randomly assigned to four groups: (i) control group; (ii) PQ group; (iii) PQ + losartan 7d group; and (iv) PQ + losartan 14d group. Losartan treatment (intragastrically (i.g.), 10 mg/kg) was performed for 7 and 14 days after a single i.g. dose of 40 mg/kg PQ. All rats were killed on the 16th day, and hematoxylin-eosin and Masson's trichrome staining were used to examine lung injury and fibrosis. The levels of hydroxyproline and transforming growth factor β1 (TGF-β1), matrix metallopeptidase 9 (Mmp9), and tissue inhibitor of metalloproteinase 1 (TIMP-1) messenger RNA (mRNA) expression and relative expression levels of collagen type I and III were also detected. PQ caused a significant increase in hydroxyproline content, mRNA expression of TGF-β1, Mmp9, and TIMP-1, and relative expression levels of collagen type I and III ( p losartan significantly decreased the amount of hydroxyproline and downregulated TGF-β1, Mmp9, and TIMP-1 mRNA and collagen type I and III expressions ( p losartan could markedly reduce such damage and prevent pulmonary fibrosis. The results of this study indicated that losartan could reduce lung damage and prevent pulmonary fibrosis induced by PQ. © The Author(s) 2014.

  13. Paraquat inhibits progesterone synthesis in human placental mitochondria.

    Science.gov (United States)

    Milczarek, Ryszard; Sokołowska, Ewa; Rybakowska, Iwona; Kaletha, Krystian; Klimek, Jerzy

    2016-07-01

    Human placenta mitochondria produces huge amounts of progesterone necessary for maintaining the pregnancy. Lipid peroxidation in human placental mitochondria inhibits progesterone synthesis and that inhibition can be reversed by superoxide dismutase and other antioxidants. Paraquat (PQ) a highly toxic herbicide generates superoxide radical inside cells and induces lipid peroxidation. Hence, it is supposed to stimulate lipid peroxidation in human placental mitochondria and in consequence to inhibit a placental mitochondrial steroidogenesis. Placentas were obtained from normal pregnancies. All experiments were done using isolated human placental mitochondria. Mitochondrial lipid peroxidation was determined as tiobarbituric acid reactive substances (TBARS). A conversion of cholesterol to pregnenolone or pregnenolone to progesterone was measured using radiolabeled steroids and thin layer chromatography. PQ enhanced the iron-dependent lipid peroxidation as also PQ heightened the inhibitory action of this process on progesterone synthesis in isolated human placental mitochondria. Paradoxically, a superoxide dismutase (SOD) reversed the inhibition of progesterone synthesis only minimally although it strongly inhibited PQ stimulated iron-dependent lipid peroxidation. When iron was absent, PQ stimulated only negligible lipid peroxidation but strongly inhibited progesterone synthesis. SOD had no effect on inhibition of progesterone synthesis by PQ. PQ strongly inhibited of the conversion of cholesterol to pregnenolone but had not got any influence on the enzymatic activity of mitochondrial 3β-hydroxysteroid dehydrogenase. PQ strongly decreased the efficiency of NADPH-dependent cytochrome P450 reduction as well as it promoted the rapid oxidation of the pre-reduced mitochondrial cytochrome P450. However PQ has not inhibited combined activity of adrenodoxin reductase and adrenodoxin. We conclude that the most important reason of the inhibition of progesterone synthesis by PQ

  14. 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

    2017-11-03

    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.

  15. 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.

  16. Evaluation of antimony microparticles supported on biochar for application in the voltammetric determination of paraquat.

    Science.gov (United States)

    Gevaerd, Ava; de Oliveira, Paulo R; Mangrich, Antonio S; Bergamini, Márcio F; Marcolino-Junior, Luiz H

    2016-05-01

    This work describes the construction and application of carbon paste electrodes modified with biochar and antimony microparticles (SbBCPE) for voltammetric determination of paraquat using a simple and sensitive procedure based on voltammetric stripping analysis. Some parameters such as amount of biochar and antimony used in the composition of the carbon paste and instrumental parameters were examined in detail. Under optimized conditions, an analytical curve was obtained for paraquat determination employing SbBCPE, which showed a linear response ranging from 0.2 to 2.9 μmol L(-1), with limit of detection and quantification of 34 nmol L(-1) and 113 nmol L(-1), respectively, after paraquat pre-concentration of 120 s. The repeatability study presented a RSD=2.0% for 10 consecutive measurements using the same electrode surface and the reproducibility study showed a RSD=2.7% for measurements with 10 different electrode surfaces. The proposed sensor was successfully applied for paraquat determination in tap water and citric fruit juice spiked samples and good recoveries were obtained without any sample pre-treatment, showing its promising analytical performance. Copyright © 2016 Elsevier B.V. All rights reserved.

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

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    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.

  18. Depuration Technique of Xenobiotics with Reference to Accumulation and Elimination of Paraquat Dichloride in Clarias Gariepinus

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    Thomas Ikpesu

    2013-09-01

    Full Text Available Background: Paraquat dichloride is a highly toxic herbicide which is still used in many developing countries. African cat fish (Clarias gariepinus is a commercially important species in many countries and was selected assess accumulation and elimination of paraquat dichloride in its tissues.Methods: Groups of ten fish with equal lengths and weights were exposed to varying concentrations of Paraquat dichloride for 28 days. After the exposure, the fish were transferred to uncontaminated water. Two fish were sampled for pesticide residue at the end of exposure period (28days and 1, 7 and 14 days post exposure. Results: In pesticide treated fish, the accumulation of paraquat increased with increases in the concentration of the toxicant and varied significantly between the treatments (p < 0.05. The herbicide depurated gradually with cessation of exposure and no pesticide was observed after 14 days. Conclusion: Xenobiotics could be eliminated from aquatic organisms especially fishes and could be put into practice in areas at risk of pollutants. This novel approach can reduce the risks of biomagnification of poisons in sea food.

  19. 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...

  20. Glyphosate and Paraquat in Maternal and Fetal Serums in Thai Women.

    Science.gov (United States)

    Kongtip, Pornpimol; Nankongnab, Noppanun; Phupancharoensuk, Ratanavadee; Palarach, Chonlada; Sujirarat, Dusit; Sangprasert, Supha; Sermsuk, Malasod; Sawattrakool, Namthip; Woskie, Susan Renee

    2017-01-01

    This longitudinal study measured the glyphosate and paraquat concentrations found in maternal and umbilical cord serum in 82 pregnant women who gave birth in three provinces of Thailand. Through questionnaires and biological samples collected at childbirth, factors such as personal characteristics, family members occupation, agricultural activities, and herbicide use in agricultural work were evaluated as predictors of glyphosate and paraquat levels in the pregnant women. Statistical analysis used univariate and binary multiple logistic regression, where the outcome was the probability of exposure to paraquat or glyphosate above the limit of detection associated with occupation and household factors. The glyphosate concentrations in the pregnant women's serum at childbirth (median: 17.5, range: 0.2-189.1 ng/mL) were significantly higher (P glyphosate levels >LOD in serum at childbirth were 11.9 times more likely to report work as an agriculturist (P glyphosate and paraquat. The potential for long-term health impacts of these prenatal exposures to children should be evaluated, and greater regulation of the sale and use of herbicides should be considered in Thailand.

  1. Paraquat-induced lightwood in two European conifers - Scotch pine and Norway spruce

    Energy Technology Data Exchange (ETDEWEB)

    Wroblewska, H.; Conner, A.H.; Rowe, J.W.; Peters, W.J.; Roberts, D.R.

    1978-04-01

    Paraquat treatment induced oleoresin-soaked lightwood in Scotch pine; borehole and ax-frill treatment methods were equally effective. Paraquat treatment of Norway spruce induced limited lightwood formation accompanied by heavy external oleoresin exudation. Thus paraquat treatment of Scotch pine and possibly Norway spruce could be commercially advantageous for increasing naval stores production from these species. Analysis of tall oil precursors (nonvolatile ether extractives) for resin acids, fatty acids, and nonsaponifiables showed that the increase from paraquat treatment was mainly from an increased resin acid content. The chemical composition of the resin acids from the lightwood and control wood areas was similar and consisted of the usual pimaric and abietic type resin acids found in conifers. The fatty acids were predominately unsaturated C/sub 18/ isomers. Turpentine of both species consisted mainly of ..cap alpha..-pinene, ..beta..-pinene, and 3-carene. The composition of the turpentine from the Scotch pine lightwood did not differ from that of the control wood. However, turpentine from the Norway spruce lightwood had an increased 3-carene content compared to that from the control.

  2. 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.

  3. Paraquat-induced resinosis in Pinus radiata. Part 3. Factors influencing oleoresin yields

    Energy Technology Data Exchange (ETDEWEB)

    Sioumis, A.A.; Smelstorius, J.A.; Lau, L.S.

    1979-01-01

    Factors affecting oleoresin yield were: the amount and mode of application of paraquat; and age, size, and dominance of the tree. In trials with 12-year old P. radiata, the bark removal technique yielded more oleoresin than the drill-hole method.

  4. NLRP3 inflammasome activation is essential for paraquat-induced acute lung injury.

    Science.gov (United States)

    Liu, Zhenning; Zhao, Hongyu; Liu, Wei; Li, Tiegang; Wang, Yu; Zhao, Min

    2015-02-01

    The innate immune response is important in paraquat-induced acute lung injury, but the exact pathways involved are not elucidated. The objectives of this study were to determine the specific role of the NLRP3 inflammasome in the process. Acute lung injury was induced by administering paraquat (PQ) intraperitoneally. NLRP3 inflammasome including NLRP3, ASC, and caspase-1 mRNA and protein expression in lung tissue and IL-1β and IL-18 levels in BALF were detected at 4, 8, 24, and 72 h after PQ administration in rats. Moreover, rats were pretreated with 10, 30, and 50 mg/kg NLRP3 inflammasome blocker glybenclamide, respectively, 1 h before PQ exposure. At 72 h after PQ administration, lung histopathology changes, NLRP3, ASC, and caspase-1 protein expression, as well as secretion of cytokines including IL-1β and IL-18 in BALF were investigated. The NLRP3 inflammasome including NLRP3, ASC, caspase-1 expression, and cytokines IL-1β and IL-18 levels in PQ poisoning rats were significantly higher than that in the control group. NLRP3 inflammasome blocker glybenclamide pretreatment attenuated lung edema, inhibited the NLRP3, ASC, and caspase-1 activation, and reduced IL-1β and IL-18 levels in BALF. In the in vitro experiments, IL-1β and IL-18 secreted from RAW264.7 mouse macrophages treated with paraquat were attenuated by glybenclamide. In conclusion, paraquat can induce IL-1β/IL-18 secretion via NLRP3-ASC-caspase-1 pathway, and the NLRP3 inflammasome is essential for paraquat-induced acute lung injury.

  5. 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.

  6. Comparative effects of the herbicides dicamba, 2,4-D and paraquat on non-green potato tuber calli.

    Science.gov (United States)

    Peixoto, Franciso P; Gomes-Laranjo, José; Vicente, Joaquim A; Madeira, Victor M C

    2008-07-31

    The effects of the herbicides 1,1'-dimethyl-4,4'-bipyridylium dichloride (paraquat), 3,6-dichloro-2-metoxybenzoic acid (dicamba) and 2,4-dichlorophenoxyacetic acid (2,4-D) on cell growth of non-green potato tuber calli are described. We attempted to relate the effects with toxicity, in particular the enzymes committed to the cellular antioxidant system. Cell cultures were exposed to the herbicides for a period of 4 weeks. Cellular integrity on the basis of fluorescein release was strongly affected by 2,4-D, followed by dicamba, and was not affected by paraquat. However, the three herbicides decreased the energy charge, with paraquat and 2,4-D being very efficient. Paraquat induced catalase (CAT) activity at low concentrations (1 microM), whereas at higher concentrations, inhibition was observed. Dicamba and 2,4-D stimulated CAT as a function of concentration. Superoxide dismutase (SOD) activity was strongly stimulated by paraquat, whereas dicamba and 2,4-D were efficient only at higher concentrations. Glutathione reductase (GR) activity was induced by all the herbicides, suggesting that glutathione and glutathione-dependent enzymes are putatively involved in the detoxification of these herbicides. Paraquat slightly inhibited glutathione S-transferase (GST), whereas 2,4-D and dicamba promoted significant activation. These results indicate that the detoxifying mechanisms for 2,4-D and dicamba may be different from the mechanisms of paraquat detoxification. However, the main cause of cell death induced by paraquat and 2,4-D is putatively related with the cell energy charge decrease.

  7. 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.

  8. Supramolecular hydrogels formed from poly(viologen cross-linked with cyclodextrin dimers and their physical properties

    Directory of Open Access Journals (Sweden)

    Yoshinori Takashima

    2012-09-01

    Full Text Available Supramolecular materials with noncovalent bonds have attracted much attention due to their exclusive properties differentiating them from materials formed solely by covalent bonds. Especially interesting are rotor molecules of topological complexes that shuttle along a polymer chain. The shuttling of these molecules should greatly improve the tension strength. Our research employs cyclodextrin (CD as a host molecule, because CD effectively forms polyrotaxanes with polymers. Herein we report the formation of supramolecular hydrogels with an α-CD dimer (α,α-CD dimer as a topological linker molecule, and a viologen polymer (VP as the polymer chain. The supramolecular hydrogel of α,α-CD dimer/VP forms a self-standing gel, which does not relax (G' > G'' in the frequency range 0.01–10 rad·s−1. On the other hand, the supramolecular hydrogel decomposes upon addition of bispyridyl decamethylene (PyC10Py as a competitive guest. Moreover, the β-CD dimer (β,β-CD dimer with VP does not form a supramolecular hydrogel, indicating that complexation between the C10 unit of VP and the α-CD unit of the α,α-CD dimer plays an important role in the formation of supramolecular hydrogels.

  9. Enhanced Adsorption and Photocatalytic Activities of Co-Doped TiO2 Immobilized on Silica for Paraquat

    Science.gov (United States)

    Nghia, Nguyen Manh; Negishi, Nobuaki; Hue, Nguyen Thi

    2018-01-01

    We studied the adsorption and photocatalysis of paraquat in an aqueous solution with cobalt-doped TiO2 supported on mesoporous silica gel. With Co concentration increasing from 0% to 9%, it was found that the TiO2 anatase phase remained unchanged and the Co was uniformly distributed, while the band gap energy decreased from 3.32 eV to 2.64 eV. The drop in band gap energy leads to the Co-TiO2/silica gel photocatalyst oxidation of paraquat to NH4 + and NO3 - products under visible light. Relative to TiO2, the incorporation of Co into TiO2 led to an increase in the adsorption ability against the paraquat. A possible mechanism of the paraquat degradation may be that the paraquat was selectively adsorbed onto the Co-TiO2/silica gel photocatalyst before light irradiation and after that the paraquat was continuously photodecomposed.

  10. Activated charcoal is as effective as fuller's earth or bentonite in paraquat poisoning.

    Science.gov (United States)

    Okonek, S; Setyadharma, H; Borchert, A; Krienke, E G

    1982-02-15

    In vitro investigations have shown that the adsorption capacity of activated charcoal ('Kohle-Compretten', 'Ultracarbon', E. Merck, Darmstadt, FRG) is just as high as that of 'Fuller's earth' (Surrey powder, Laporte Industries Ltd., Luton, GB) or 'Bentonite BP W.B. (Steetley Minerals Ltd., Milton Keynes, GB). Fuller's earth ('Fullererde') from another manufacturer has had very poor adsorption properties and is thus not suitable for the treatment of paraquat poisoning. Animal experiments have shown that the curative effect of activated charcoal given 0.5, 1, 2, and 3 h after ingestion of 200 and 300 mg paraquat/kg body weight is equally as good or even better than that of 'Fuller's earth' or 'Bentonite BP W.B' Activated charcoal is a substitute of equal value to these mineral soils.

  11. 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

    Directory of Open Access Journals (Sweden)

    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

  12. Unveiling the role of the pesticides paraquat and rotenone on α-synuclein fibrillation in vitro.

    Science.gov (United States)

    Maturana, Maurício Guilherme Valente; Pinheiro, Anderson Sá; de Souza, Theo Luiz Ferraz; Follmer, Cristian

    2015-01-01

    Epidemiological data have suggested that exposure to environmental toxins might be associated with the etiology of Parkinson's disease (PD). In this context, certain agrochemicals are able to induce Parkinsonism in different animal models via the inhibition of mitochondrial complex I, which leads to an increase in both oxidative stress and the death of nigrostriatal neurons. Additionally, in vitro experiments have indicated that pesticides are capable of accelerating the fibrillation of the presynaptic protein α-synuclein (aS) by binding directly to the protein. However, the molecular details of these interactions are poorly understood. In the present work we demonstrate that paraquat and rotenone, two agrochemicals that lead to a Parkinsonian phenotype in vivo, bind to aS via solvent effects rather than through specific interactions. In fact, these compounds produced no significant effects on aS fibrillation under physiological concentrations of NaCl. NMR data suggest that paraquat interacts with the C-terminal domain of the disordered aS monomer. This interaction was markedly reduced in the presence of NaCl, presumably due to the disruption of electrostatic interactions between the protein and paraquat. Interestingly, the effects produced by short-term incubation of paraquat with aS on the protein conformation resembled those produced by incubating the protein with NaCl alone. Taken together, our data indicate that the effects of these agrochemicals on PD cannot be explained via direct interactions with aS, reinforcing the idea that the role of these compounds in PD is limited to the inhibition of mitochondrial complex I and/or the up-regulation of aS. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Effect of Brief Exposure to Paraquat on Some Blood Parameters of ...

    African Journals Online (AJOL)

    Clarias gariepinus (mean weight, 100.34 ± 8.13g SD; mean total length, 19.02 ± 4.32 cm SD) were exposed (four fish/tank) to 0, 1.25, 2.50 and 5.00 mgl-1 paraquat solution in triplicate in rectangular glass aquaria (60.9 x 30.4 x 30.4 cm3) under a static condition for 72 hours to determine the effect of exposure on the ...

  14. Study of the removal of paraquat from aqueous solution by biosorption onto Ayous (Triplochiton schleroxylon) sawdust

    Energy Technology Data Exchange (ETDEWEB)

    Nanseu-Njiki, Charles Peguy; Dedzo, Gustave Kenne [Laboratoire de Chimie Analytique, Faculte des Sciences, Universite de Yaounde I, B.P. 812 Yaounde (Cameroon); Ngameni, Emmanuel, E-mail: engameni@yahoo.fr [Laboratoire de Chimie Analytique, Faculte des Sciences, Universite de Yaounde I, B.P. 812 Yaounde (Cameroon)

    2010-07-15

    This study concerns the batch biosorption of paraquat on Ayous (Triplochiton schleroxylon) sawdust; the study centers on the evolution of biosorption parameters during the process. It appears that paraquat forms a monolayer on the sawdust surface as evidenced by the good correlation between the experimental data and the Langmuir model. The biosorption which is rather fast (the equilibrium was reached after ten minutes) follows a pseudo-second-order kinetic model and does not obey to the intra-particle diffusion model. According to the mathematical kinetic modeling, pore and surface mass transfer well describe the phenomenon. NaCl reduces the adsorption capacity of the material but has no significant effect on the kinetics. Alkaline solutions enhance the accumulation of the pollutant, the reverse being observed for acidic media. According to the thermodynamic data, this biosorption is a spontaneous and exothermic process. From these results we concluded that the adsorption of the pollutant is mainly due to cation exchange as indicated by the adsorption energy determined by the Dubinin-Radushkevich model (E = 12.0736 kJ mol{sup -1}); some other interactions resulting from the affinity through organophilic interactions between paraquat and sawdust have also been pointed out. Desorption experiments conducted in HCl and HNO{sub 3} solutions confirmed the proposed mechanism.

  15. Prenatal Paraquat exposure induces neurobehavioral and cognitive changes in mice offspring.

    Science.gov (United States)

    Ait-Bali, Yassine; Ba-M'hamed, Saadia; Bennis, Mohammed

    2016-12-01

    In the present work, we investigated developmental toxicity of Paraquat (PQ), from the 1st or 6th day of mating and throughout the gestation period. We have examined several parameters, including toxicity indices, reproductive performance, sensorimotor development, as well as anxiety and cognitive performance of the offspring. Our results showed that exposure to 20mg/kg of Paraquat during the first days of pregnancy completely prevents pregnancy in treated mice, but from the 6th day of pregnancy, an alteration in fertility and reproductive parameters was observed. In offspring, the PQ was responsible for an overall delay of innate reflexes and a deficit in motor development. All exposed animals showed a decrease in the level of locomotor activity, increased levels of anxiety-like behavior and pronounced cognitive impairment in adulthood. These results demonstrated that Paraquat led to the onset of many behavioral changes that stem from the impairment of neuronal developmental processes in prenatally exposed mice. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Absolute Lymphocyte Count as a Predictor of Mortality in Emergency Department Patients with Paraquat Poisoning

    Science.gov (United States)

    Kang, Changwoo; Kim, Seong Chun; Lee, Soo Hoon; Jeong, Jin Hee; Kim, Dong Seob; Kim, Dong Hoon

    2013-01-01

    Background Paraquat (PQ) is a potent, highly toxic and widely used herbicide. The major medical problems associated with PQ are accidental or suicidal ingestion. There are several prognostic markers of PQ poisoning, with the serum PQ concentration considered to be the best indicator of outcome. However, the measurement of such markers is limited in many hospitals. Objective The present study was conducted to investigate the association of absolute lymphocyte count (ALC) and the 30-day mortality rate in patients with PQ poisoning. Methods We performed a retrospective analysis of patients admitted to the emergency department after paraquat poisoning between January 2010 and April 2013. Independent risk factors including ALC for 30-day mortality were determined. The ALC was categorized in quartiles as ≤1700, 1700 to 3200, 3200 to 5000, and >5000. Univariate and multivariate Cox proportional hazard analysis were performed to determine the independent risk factors for mortality. Results A total of 136 patients were included in the study, and the 30-day mortality was 73.5%. ALC was significantly higher in nonsurvivors than in survivors. The highest ALC quartile (ALC>5000; hazard ratio, 2.58; 95% CI, 1.08–6.21) was associated with increased mortality in multivariate analysis. In addition, old age, lower arterial PaCO2, increased peripheral neutrophil count, and high serum levels of creatinine were associated with mortality. Conclusion The absolute lymphocyte count is associated with the 30-day mortality rate in patients with paraquat poisoning. PMID:24205140

  17. Adsorption of herbicide paraquat by clay mineral regenerated from spent bleaching earth.

    Science.gov (United States)

    Tsai, Wen-Tien; Lai, Chi-Wei

    2006-06-30

    The adsorption of herbicide paraquat (as model adsorbate) in aqueous solution onto regenerated clay mineral from bleaching earth waste has been studied in a batch reaction system. The adsorption rate has been investigated under the controlled process parameters including initial pH, salinity and temperature. Based on the high affinity between cationic paraquat and clay mineral, a pseudo-second order model has been developed using experimental data to predict the rate constant of adsorption, and equilibrium adsorption capacity. The results showed that the adsorption process could be satisfactorily described with the reaction model and were reasonably explained by assuming a competitive adsorption mechanism in the ion exchange process. Further, the fitted adsorption capacity at equilibrium decreased with increasing temperature. It implied that the strong interaction might play an important role in the paraquat-clay system. Overall, the results from this study demonstrated that the clay resource regenerated from bleaching earth waste could be used as a low-cost mineral adsorbent for the removal of environmental cationic organic pollutants from the aqueous solution.

  18. Determination of herbicides paraquat, glyphosate, and aminomethylphosphonic acid in marijuana samples by capillary electrophoresis.

    Science.gov (United States)

    Lanaro, Rafael; Costa, José L; Cazenave, Silvia O S; Zanolli-Filho, Luiz A; Tavares, Marina F M; Chasin, Alice A M

    2015-01-01

    In this work, two methods were developed to determine herbicides paraquat, glyphosate, and aminomethylphosphonic acid (AMPA) in marijuana samples by capillary electrophoresis. For paraquat analysis, sample was extracted with aqueous acetic acid solution and analyzed by capillary zone electrophoresis with direct UV detection. The running electrolyte was 50 mmol/L phosphate buffer (pH 2.50). For glyphosate and AMPA, indirect UV/VIS detection was used, as these substances do not present chromophoric groups. Samples were extracted with 5 mmol/L hydrochloric acid. The running electrolyte was 10 mmol/L gallic acid, 6 mmol/L TRIS, and 0.1 mmol/L CTAB (pH = 4.7). The methods presented good linearity, precision, accuracy, and recovery. Paraquat was detected in 12 samples (n = 130), ranging from 0.01 to 25.1 mg/g. Three samples were positive for glyphosate (0.15-0.75 mg/g), and one sample presented AMPA as well. Experimental studies are suggested to evaluate the risks of these concentrations to marijuana user. © 2014 American Academy of Forensic Sciences.

  19. 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.

  20. Electron-transfer kinetics in cyanobacterial cells: methyl viologen is a poor inhibitor of linear electron flow.

    Science.gov (United States)

    Sétif, Pierre

    2015-02-01

    The inhibitor methyl viologen (MV) has been widely used in photosynthesis to study oxidative stress. Its effects on electron transfer kinetics in Synechocystis sp. PCC6803 cells were studied to characterize its electron-accepting properties. For the first hundreds of flashes following MV addition at submillimolar concentrations, the kinetics of NADPH formation were hardly modified (less than 15% decrease in signal amplitude) with a significant signal decrease only observed after more flashes or continuous illumination. The dependence of the P700 photooxidation kinetics on the MV concentration exhibited a saturation effect at 0.3 mM MV, a concentration which inhibits the recombination reactions in photosystem I. The kinetics of NADPH formation and decay under continuous light with MV at 0.3 mM showed that MV induces the oxidation of the NADP pool in darkness and that the yield of linear electron transfer decreased by only 50% after 1.5-2 photosystem-I turnovers. The unexpectedly poor efficiency of MV in inhibiting NADPH formation was corroborated by in vitro flash-induced absorption experiments with purified photosystem-I, ferredoxin and ferredoxin-NADP(+)-oxidoreductase. These experiments showed that the second-order rate constants of MV reduction are 20 to 40-fold smaller than the competing rate constants involved in reduction of ferredoxin and ferredoxin-NADP(+)-oxidoreductase. The present study shows that MV, which accepts electrons in vivo both at the level of photosystem-I and ferredoxin, can be used at submillimolar concentrations to inhibit recombination reactions in photosystem-I with only a moderate decrease in the efficiency of fast reactions involved in linear electron transfer and possibly cyclic electron transfer. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. 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.

  2. A new type of charge-transfer salts based on tetrathiafulvalene-tetracarboxylate coordination polymers and methyl viologen.

    Science.gov (United States)

    Huang, Yu-De; Huo, Peng; Shao, Ming-Yan; Yin, Jing-Xue; Shen, Wei-Chun; Zhu, Qin-Yu; Dai, Jie

    2014-04-07

    Although charge-transfer compounds based on tetrathiafulvalene (TTF) derivatives have been intensively studied, {[cation](n+)·[TTFs](n-)} ion pair charge-transfer (IPCT) salts have not been reported. The aim of this research is to introduce functional organic cations, such as photoactive methyl viologen (MV(2+)), into the negatively charged TTF-metal coordination framework to obtain this new type of IPCT complex. X-ray structural analysis of the four compounds (MV)2[Li4(L)2(H2O)6] (1), {(MV)(L)[Na2(H2O)8]·4H2O}n (2), {(MV)[Mn(L)(H2O)2]·2H2O}n (3), and {(MV)[Mn(L)(H2O)2]}n (4), reveals that the electron donor (D) TTF moiety and the electron acceptor (A) MV(2+) form a regular mixed-stack arrangement in alternating DADA fashion. The TTF moiety and the MV(2+) cation are essentially parallel stacked to form the column structures. The strong electrostatic interaction is a main force to shorten the distance between the cation and anion planes. Optical diffuse-reflection spectra indicate that charge transfer occurs in these complexes. The ESR and magnetic measurements confirm that there is strong charge-transfer-induced partial electron transfer. Compounds 2, 3, and 4 show an effective and repeatable photocurrent response. The current intensities of 3 and 4 are higher than that of 2, which reflects that the coordination center of the Mn(II) ion has a great effect on the increasing photocurrent response.

  3. 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.

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

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    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

  5. NLRP3 inflammasome activation regulated by NF-κB and DAPK contributed to paraquat-induced acute kidney injury.

    Science.gov (United States)

    Liu, Zhenning; Wang, Xiaokai; Wang, Yu; Zhao, Min

    2017-06-01

    Paraquat can result in dysfunction of multiple organs after ingestion in human. However, the mechanisms of nucleotide-binding domain and leucine-rich repeat containing protein 3 (NLRP3) inflammasome activation in acute kidney injury have not been clearly demonstrated. The aim of this study was to determine the effect of NLRP3 inflammasome activation and its regulation by nuclear factor-kappa B (NF-κB) and death-associated protein kinase (DAPK). Male Wistar rats were treated with intraperitoneal injection of paraquat at 20 mg/kg, and NF-κB inhibitor BAY 11-7082 was pretreated at 10 mg/kg 1 h before paraquat exposure. Additionally, rat renal tubular epithelial cells (NRK-52E) were transfected with small interfering RNA (siRNA) against DAPK to evaluate its role in NLRP3 inflammasome activation. DAPK and NLRP3 inflammasome were evaluated by immunohistochemistry staining or Western blot; the pro-inflammatory cytokines including tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), and interleukin-18 (IL-18) were measured via ELISA. The results showed that NF-κB, DAPK, and NLRP3 inflammasome were activated in paraquat (PQ)-treated rat kidney; the secretion of pro-inflammatory cytokines was significantly increased. These toxic effects were attenuated by NF-κB inhibitor. Besides, the activation of NLRP3 inflammasome and secretion of IL-1β and IL-18 in paraquat-treated rat renal tubular epithelial cells were inhibited by siRNA against DAPK. In conclusion, NLRP3 inflammasome activation regulated by NF-κB and DAPK played an important role in paraquat-induced acute kidney injury.

  6. Successful treatment of paraquat poisoning by Xuebijing, an injection concocted from multiple Chinese medicinal herbs: a case report.

    Science.gov (United States)

    Sun, Ming-li; Ma, Di-hui; Liu, Min; Yu, Ya-xin; Cao, Dian-bo; Ma, Chi; Wang, Xu; Liu, Xiao-liang

    2009-12-01

    1,1'-Dimethyl-4,4'-bipyridinium dichloride (Paraquat) poisoning remains a significant global health problem. Despite noteworthy research and clinical efforts worldwide in the last few decades, little improvement has been made in reducing fatality from Paraquat poisoning with conventional treatment strategies. We herein report a case of successful management of Paraquat poisoning by Xuebijing, a newly developed injection concocted from multiple traditional Chinese medicinal herbs. A 25-year-old male patient was brought to the Emergency Department at the First Affiliated Hospital of Jilin University in Changchun, China approximately 23 hours after ingestion of approximately 50 mL of 20% (w/v) Paraquat in a suicide attempt. On admission, the patient presented with clinical symptoms as well as significantly abnormal results in the liver and kidney function tests that were typical of severe Paraquat poisoning. Following the routine emergency procedures for pesticide poisoning to minimize the poison exposure and relieve the poisoning symptoms, an intravenous drip of Xuebijing together with dexamethasone was given daily to the patient until discharge 10 days after admission. The patient was followed up for 15 months after discharge, during which monthly chest radiography was performed. Treatment outcomes: At the time of discharge, the patient had recovered well: His symptoms of poisoning in the mouth and gastrointestinal tract were all diminishing; his liver and kidney functions were recovering with the major test parameters improving; his chest radiograph was clear, showing no signs of pulmonary fibrosis. During the postdischarge follow-up period, the monthly chest radiographs were all normal. This case report suggests that Xuebijing has great potential as a novel effective alternative to the conventional management of Paraquat poisoning. This potential needs to be further evaluated in a substantially larger number of clinical cases in the future.

  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. Effect of paraquat on the incorporation of /sup 14/C-leucine and /sup 14/C-palmitate into lung proteins and lung lipids of rats and rabbits

    Energy Technology Data Exchange (ETDEWEB)

    Engelbrecht, F.M.; Rossouw, D.J.; Nienaber, M.W.P. (Stellenbosch Univ., Parowvallei (South Africa). Dept. of Physiology and Biochemistry)

    1981-06-20

    The results of this comparative study show that paraquat added in vitro inhibited lipid and protein biosynthesis by lung slices from rats and rabbits during the first 2 hours of incubation. This inhibition was maintained in spite of an increased oxygen uptake and pentose pathway activity during this period. Paraquat (1mM) added in vitro caused significant inhibition of /sup 14/C-leucine and /sup 14/C-palmitate incorporation into the soluble proteins and total lipids respectively of rat and rabbit lung slices. The effect of paraquat (27 mg/kg) administered intraperitoneally to rats and rabbits and assessed on the rate of /sup 14/C-leucine incorporation in vitro 24 hours after injection, also showed a significant inhibition. However, after 48 hours, protein synthesis was stimilated in rat lungs, whereas paraquat had no effect on rabbit lungs. A highly significant suppression of the rate of /sup 14/C-palmitate incorporation 24 hours after intraperitoneal injection of paraquat was found with rat lung slices, whereas with rabbit lung slices the degree of inhibition was not significant. Forty-eight hours after injection a highly significant inhibition was maintained in rat lung slices while rabbit lung slices showed no inhibition. This finding points to a species difference in the effect of paraquat on metabolic processes and may explain the resistance of rabbit lung to damage by paraquat.

  9. 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.

  10. Sensitive determination of paraquat by square wave anodic stripping voltammetry with chitin modified carbon paste electrode.

    Science.gov (United States)

    El Harmoudi, H; Achak, M; Farahi, A; Lahrich, S; El Gaini, L; Abdennouri, M; Bouzidi, A; Bakasse, M; El Mhammedi, M A

    2013-10-15

    A novel analytical approach has been developed and evaluated for the quantitative analysis of paraquat herbicides which can be found at trace levels in olive oil and olives. The aim of this work is to optimize all factors that can influence this determination by a carbon paste electrode modified with chitin (Chit-CPE). The best responses were obtained with square wave potential in diluted Na2SO4 as supporting electrolyte. The influence of various parameters on the Chit-CPE was investigated. Under the optimized working conditions, calibration graphs were linear in the concentration ranges of 5.0 × 10(-9)-1.0 × 0(-5) mol L(-1). For 180 s preconcentration, detection limits of 2.67 × 10(-10) mol L(-1) (peak 2) was obtained at the signal noise ratio (SNR) of 3. To evaluate the reproducibility of the newly developed electrode, the measurements of 1.0 × 10(-5) mol L(-1) PQ were carried out for seven times at Chit-CPE and the relative standard deviation was 5.2%. The analytical methodology was successfully applied to monitor the paraquat content in olives and olive oil. © 2013 Elsevier B.V. All rights reserved.

  11. 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.

  12. The effects of polyphenols on survival and locomotor activity in Drosophila melanogaster exposed to iron and paraquat.

    Science.gov (United States)

    Jimenez-Del-Rio, M; Guzman-Martinez, C; Velez-Pardo, C

    2010-02-01

    Parkinson's disease (PD) is a common progressive neurodegenerative disorder, for which at present no causal treatment is available. On the understanding that the causes of PD are mainly oxidative stress and mitochondrial dysfunction, antioxidants and other drugs are expected to be used. In the present study, we demonstrated for the first time that pure polyphenols such as gallic acid, ferulic acid, caffeic acid, coumaric acid, propyl gallate, epicatechin, epigallocatechin, and epigallocatechin gallate protect, rescue and, most importantly, restore the impaired movement activity (i.e., climbing capability) induced by paraquat in Drosophila melanogaster, a valid model of PD. We also showed for the first time that high concentrations of iron (e.g. 15 mM FeSO(4)) are able to diminish fly survival and movement to a similar extent as (20 mM) paraquat treatment. Moreover, paraquat and iron synergistically affect both survival and locomotor function. Remarkably, propyl gallate and epigallocatechin gallate protected and maintained movement abilities in flies co-treated with paraquat and iron. Our findings indicate that pure polyphenols might be potent neuroprotective agents for the treatment of PD against stressful stimuli.

  13. Cellular Senescence Is Induced by the Environmental Neurotoxin Paraquat and Contributes to Neuropathology Linked to Parkinson's Disease

    NARCIS (Netherlands)

    Chinta, Shankar J.; Woods, Georgia; Demaria, Marco; Rane, Anand; Zou, Ying; McQuade, Amanda; Rajagopalan, Subramanian; Limbad, Chandani; Madden, David T.; Campisi, Judith; Andersen, Julie K.

    2018-01-01

    Exposure to the herbicide paraquat (PQ) is associated with an increased risk of idiopathic Parkinson's disease (PD). Therapies based on PQ's presumed mechanisms of action have not, however, yielded effective disease therapies. Cellular senescence is an anticancer mechanism that arrests proliferation

  14. Removal of paraquat pesticide from aqueous solutions using a novel adsorbent material based on polyacrylamide and methylcellulose hydrogels

    Science.gov (United States)

    This research studied the characteristics of poly(acrylamide) and methylcellulose (PAAm-MC) hydrogels as a novel adsorbent material for removal of pesticide paraquat, from aqueous solution, with potential applications in curbing environmental risk from such herbicides. PAAm-MC hydrogels with differe...

  15. A Nitrite Biosensor Based on Co-immobilization of Nitrite Reductase and Viologen-modified Chitosan on a Glassy Carbon Electrode

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    De Quan

    2010-06-01

    Full Text Available An electrochemical nitrite biosensor based on co-immobilization of copper- containing nitrite reductase (Cu-NiR, from Rhodopseudomonas sphaeroides forma sp. denitrificans and viologen-modified chitosan (CHIT-V on a glassy carbon electrode (GCE is presented. Electron transfer (ET between a conventional GCE and immobilized Cu-NiR was mediated by the co-immobilized CHIT-V. Redox-active viologen was covalently linked to a chitosan backbone, and the thus produced CHIT-V was co-immobilized with Cu-NiR on the GCE surface by drop-coating of hydrophilic polyurethane (HPU. The electrode responded to nitrite with a limit of detection (LOD of 40 nM (S/N = 3. The sensitivity, linear response range, and response time (t90% were 14.9 nA/mM, 0.04−11 mM (r2 = 0.999 and 15 s, respectively. The corresponding Lineweaver-Burk plot showed that the apparent Michaelis-Menten constant (KMapp was 65 mM. Storage stability of the biosensor (retaining 80% of initial activity was 65 days under ambient air and room temperature storage conditions. Reproducibility of the sensor showed a relative standard deviation (RSD of 2.8% (n = 5 for detection of 1 mM of nitrite. An interference study showed that anions commonlyfound in water samples such as chlorate, chloride, sulfate and sulfite did not interfere with the nitrite detection. However, nitrate interfered with a relative sensitivity of 64% and this interference effect was due to the intrinsic character of the NiR employed in this study.

  16. Viologen-functionalized single-walled carbon nanotubes as carrier nanotags for electrochemical immunosensing. Application to TGF-β1 cytokine.

    Science.gov (United States)

    Sánchez-Tirado, Esther; Arellano, Luis M; González-Cortés, Araceli; Yáñez-Sedeño, Paloma; Langa, Fernando; Pingarrón, José M

    2017-12-15

    Viologen-SWCNT hybrids are synthesized by aryl-diazonium chemistry in the presence of isoamyl nitrite followed by condensation reaction of the resulting HOOC-Phe-SWCNT with 1-(3-aminoethyl)-4,4'-bipyridinium bromine and N-alkylation with 2-bromoethylamine. The V-Phe-SWCNT hybrids were characterized by using different spectroscopic techniques (FT-IR, Raman, UV-vis), TGA and Kaiser test. Viologen-SWCNTs were used for the preparation of an electrochemical immunosensor for the determination of the transforming growth factor β1 (TGF-β1) cytokine considered as a reliable biomarker in several human diseases. The methodology involved preparation of V-Phe-SWCNT(-HRP)-anti-TGF conjugates by covalent linkage of HRP and anti-TGF onto V-Phe-SWCNT hybrids. Biotinylated anti-TGF antibodies were immobilized onto 4-carboxyphenyl-functionalized SPCEs modified with streptavidin and a sandwich type immunoassay was implemented for TGF-β1 with signal amplification using V-Phe-SWCNT(-HRP)-anti-TGF conjugates as carrier tags. The analytical characteristics exhibited by the as prepared immunosensor (range of linearity between 2.5 and 1000pgmL-1 TGF-β1; detection limit of 0.95pgmL-1) improve notably those reported with other previous immunosensors or ELISA kits. A great selectivity against other proteins was also found. The prepared immunosensor was validated by determining TGF-β1 in real saliva samples. Minimal sample treatment was required and the obtained results were in excellent agreement with those obtained by using a commercial ELISA kit. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Evaluation of the genotoxicity and fetal toxicity of the herbicide Paraquat Avaliação da genotoxicidade e da toxicidade fetal do herbicida Paraquat

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    Suzana de Fatima Paccola Mesquita

    1999-07-01

    Full Text Available A genotoxicidade e a toxicidade fetal do Paraquat foram avaliadas em camundongos fêmeas após tratamento agudo e subcutâneo do herbicida em diferentes períodos gestacionais. Foram utilizados o teste do micronúcleo (MN em eritrócitos de sangue periférico e a avaliação de perdas embrionárias. Os resultados deste trabalho mostraram que o tratamento agudo com a menor dose testada, 10mg/kg pc (peso corpóreo, no período de pós-implantação, não produziu diminuição significativa do tamanho da prole. Observou-se genotoxicidade 24 e 30 horas após o tratamento de animais que receberam esta dosagem no 9º e 3º dia de prenhez, respectivamente. Nossos dados sugerem, ainda, que o tratamento in vivo, com a menor dose, induz perdas embrionárias em fêmeas expostas ao agente no período de pré-implantação. A dose de 20mg/kg pc não mostrou efeito genotóxico após 24 horas do tratamento, provavelmente por ter induzido seleção celular devido à alta toxicidade do herbicida. Esta dose causou a morte dos animais, impedindo as análises de MN após 30 horas do tratamento e da toxicidade fetal.The genotoxicity and fetal toxicity of the herbicide Paraquat was assessed in female mice treated with acute subcutaneous doses of the herbicide at different stages of pregnancy. The micronucleus test (MN in peripheral blood erythrocytes and an evaluation of embryonic losses were applied. The results of the present work demonstrate that a single acute treatment in the period after-implantation did not produce a significant reduction in the size of the offspring at the lower dosage tested, 10 mg/kg bw (body weight. Genotoxicity was observed at 24 and 30 hours after treatment in animals receiving this dosage on the ninth and third day of pregnancy respectively. Our data suggest that the in vivo treatment with the lower herbicide dose induces embryonic losses in females exposed to the agent during the pre-implantation period. The dose of 20 mg/kg bw did not

  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. 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.

  1. An electrochemical magneto immunosensor (EMIS) for the determination of paraquat residues in potato samples.

    Science.gov (United States)

    Garcia-Febrero, Raul; Valera, Enrique; Muriano, Alejandro; Pividori, M-Isabel; Sanchez-Baeza, Francisco; Marco, M-Pilar

    2013-09-01

    An electrochemical magneto immunosensor for the detection of low concentrations of paraquat (PQ) in food samples has been developed and its performance evaluated in a complex sample such as potato extracts. The immunosensor presented uses immunoreagents specifically developed for the recognition of paraquat, a magnetic graphite-epoxy composite (m-GEC) electrode and biofunctionalized magnetic micro-particles (PQ1-BSAMP) that allow reduction of the potential interferences caused by the matrix components. The amperometric signal is provided by an enzymatic probe prepared by covalently linking an enzyme to the specific antibodies (Ab198-cc-HRP). The use of hydroquinone, as mediator, allows recording of the signal at a low potential, which also contributes to reducing the background noise potentially caused by the sample matrix. The immunocomplexes formed on top of the modified MP are easily captured by the m-GEC, which acts simultaneously as transducer. PQ can be detected at concentrations as low as 0.18 ± 0.09 μg L(-1). Combined with an efficient extraction procedure, PQ residues can be directly detected and accurately quantified in potato extracts without additional clean-up or purification steps, with a limit of detection (90% of the maximum signal) of 2.18 ± 2.08 μg kg(-1), far below the maximum residue level (20 μg kg(-1)) established by the EC. The immunosensor presented here is suitable for on-site analysis. Combined with the use of magnetic racks, multiple samples can be run simultaneously in a reasonable time.

  2. Assessment of occurrence and concentrations of paraquat dichloride in water, sediments and fish from Warri River Basin, Niger Delta, Nigeria.

    Science.gov (United States)

    Ikpesu, Thomas Ohwofasa

    2015-06-01

    The distribution of Paraquat dichloride in different matrices of Warri River, Western Niger Delta, Nigeria was examined. The samplings and physicochemical parameters of the river were carried out during the dry and wet seasons, and stations were visited on monthly basis. The downstream stations had significant (p water, the pesticide level was higher in the dry season than in wet season, and there was no significant difference between the seasons (p > 0.05). The reverse was the case for sediments and fish. The physicochemical parameters of the river's water were within the recommended limits accepted by Federal Environmental Protection Agency, Nigeria. The observed Paraquat dichloride concentrations were above ecological bench, an observation that calls for regular monitoring and strict law enforcement to develop a strategy to manage environmental hazards and to improve environmental protection of this area.

  3. The synthesis of pillar[5]arene functionalized graphene as a fluorescent probe for paraquat in living cells and mice.

    Science.gov (United States)

    Mao, Xiaowei; Liu, Ting; Bi, Jiahai; Luo, Li; Tian, Demei; Li, Haibing

    2016-03-21

    As complex organisms vary in vivo, it remains a challenging task to get fluorescence 'turn on' imaging for special targets. To address this task, we have adopted a new strategy of inducing pillararene based host-guest interactions onto biocompatible graphene. By means of fluorescence competition displacement, hydrazino-pillar[5]arene modified graphene has been synthesized and provided as a 'turn on' probe for paraquat through monitoring of the fluorescence signal both in living cells and mice.

  4. 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.

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

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    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.

  6. Palladium-directed self-assembly of multi-titanium(IV)-porphyrin arrays on the substrate surface as sensitive ultrathin films for hydrogen peroxide sensing, photocurrent generation, and photochromism of viologen

    Science.gov (United States)

    He, Wen-Li; Fang, Fang; Ma, Dong-Mei; Chen, Meng; Qian, Dong-Jin; Liu, Minghua

    2018-01-01

    Multiporphyrin arrays are large, π-conjugated chromophores with high absorption efficiency and strong chemical stability that play an important role in supramolecular and advanced material sciences. Palladium-directed self-assembly of multiporphyrin array ultrathin films was achieved on substrate surfaces using oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium (IV) complex [TiO(TPyP)] as a linker and sodium tetrachloropalladate (Na2PdCl4) as a connector. The Pd-TiOTPyP films as prepared were characterized by using UV-vis absorption and X-ray photoelectron spectroscopy, as well as by atomic force and scanning electron microscopy. The Soret absorption band of TiOTPyP was observed to red shift by 6 nm when the Pd-TiOTPyP multilayer-modified quartz substrate was immersed in an aqueous solution containing hydrogen peroxide. This was attributed to the formation of a TiO2TPyP monoperoxo complex. This oxidation reaction could be accelerated in an acidic solution. Furthermore, the immobilized Pd-TiOTPyP multilayers could act as light-harvesting units for photocurrent generation and photochromism of viologens, with strong stability, reproducibility, and recyclability. The photocurrent density could be enhanced in electrolyte solutions containing electron donors such as triethanolamine, or electron acceptors such as viologens. Finally, photoinduced reduction (photochromism) of viologens was investigated using the Pd-TiOTPyP multilayers as light sensitizers and EDTA as the electron donors.

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

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    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.

  8. Transcription of putative tonoplast transporters in response to glyphosate and paraquat stress in Conyza bonariensis and Conyza canadensis and selection of reference genes for qRT-PCR.

    Science.gov (United States)

    Moretti, Marcelo L; Alárcon-Reverte, Rocio; Pearce, Stephen; Morran, Sarah; Hanson, Bradley D

    2017-01-01

    Herbicide resistance is a challenge for modern agriculture further complicated by cases of resistance to multiple herbicides. Conyza bonariensis and Conyza canadensis are invasive weeds of field crops, orchards, and non-cropped areas in many parts of the world. In California, USA, Conyza populations resistant to the herbicides glyphosate and paraquat have recently been described. Although the mechanism conferring resistance to glyphosate and paraquat in these species was not elucidated, reduced translocation of these herbicides was observed under experimental conditions in both species. Glyphosate and paraquat resistance associated with reduced translocation are hypothesized to be a result of sequestration of herbicides into the vacuole, with the possible involvement of over-expression of genes encoding tonoplast transporters of ABC-transporter families in cases of glyphosate resistance or cationic amino acid transporters (CAT) in cases of paraquat resistance. However, gene expression in response to herbicide treatment has not been studied in glyphosate and paraquat resistant populations. In the current study, we evaluated the transcript levels of genes possibly involved in resistance using real-time PCR. First, we evaluated eight candidate reference genes following herbicide treatment and selected three genes that exhibited stable expression profiles; ACTIN, HEAT-SHOCK-PROTEIN-70, and CYCLOPHILIN. The reference genes identified here can be used for further studies related to plant-herbicide interactions. We used these reference genes to assay the transcript levels of EPSPS, ABC transporters, and CAT in response to herbicide treatment in susceptible and resistant Conyza spp. lines. No transcription changes were observed in EPSPS or CAT genes after glyphosate or paraquat treatment, suggesting that these genes are not involved in the resistance mechanism. Transcription of the two ABC transporter genes increased following glyphosate treatment in all Conyza spp. lines

  9. 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

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    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.

  10. [Determination of paraquat and diquat in drinking water and environmental water by high performance liquid chromatography coupled with on-line clean-up and solid phase extraction].

    Science.gov (United States)

    Chen, Jing; Liu, Zhaojin; An, Baochao; Lu, Yan; Xu, Qun

    2012-10-01

    An on-line solid phase extraction (SPE) system was used to eliminate the interferences sufficiently and fulfill the simple and sensitive determination of diquat and paraquat in tap and pond water. This on-line SPE system used two SPE cartridges. One was an Acclaim Mixed-Mode WAX-1 cartridge for the elimination of anionic interferences; the other one was an Acclaim Mixed-Mode WCX-1 cartridge for the enrichment of diquat and paraquat and the elimination of co-enriched cationic interferences. The baseline separation of diquat and paraquat was achieved on an Acclaim Trinity P1 column. A dual-gradient high performance liquid chromatographic (HPLC) system provided an efficient platform to fulfill the on-line SPE and separation, and the system operated under automatic control of chromatography data system software. The complete analysis only required 16 min, and the detection limits of the method were 0.12 microg/L for diquat and 0.10 microg/L for paraquat. The method is simple, rapid and sensitive, and can be applied to the determination of diquat and paraquat in drinking water and environmental water.

  11. Regulator of G protein signaling-1 modulates paraquat-induced oxidative stress and longevity via the insulin like signaling pathway in Caenorhabditis elegans.

    Science.gov (United States)

    Wu, Mingyu; Kang, Xin; Wang, Qiang; Zhou, Chunyu; Mohan, Chandra; Peng, Ai

    2017-05-05

    Insulin or insulin like signaling (IIS) pathway is a crucial pathway in Caenorhabditis elegans associated with mediating longevity, and stress resistance. Regulators of G protein signaling (RGS) also modulate stress resistance and longevity in multiple in vitro and in vivo models. However, the mechanism underlying RGS mediating stress resistance and longevity remains largely unclear. Here we report that rgs-1, an important member of rgs family, is a novel modulator of IIS pathway in C. elegans. We found that the loss of rgs-1 dramatically promoted paraquat resistance in C. elegans. Further genetic analyses demonstrated that rgs-1 acted downstream of daf-2 and upstream of age-1, pdk-1, daf-16. Instead of affecting those IIS-associated genes in transcriptional process, loss of rgs-1 promoted DAF-16's nucleus translocation and subset genes' expression in paraquat-induced oxidative status. By this way, rgs-1 mutant worms exhibited lower ROS damage and longer survival time than wild type worms when both exposed to paraquat. Other than paraquat exposure, rgs-1 mutant also promoted lifespan and cadmium resistance relying on daf-16. As rgs is evolutionarily conserved, our findings open a new insight into rgs family and its role in paraquat-induced oxidative stress and longevity in C. elegans or even mammals. Copyright © 2017 Elsevier B.V. All rights reserved.

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

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    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.

  13. An efficient machine learning approach for diagnosis of paraquat-poisoned patients.

    Science.gov (United States)

    Hu, Lufeng; Hong, Guangliang; Ma, Jianshe; Wang, Xianqin; Chen, Huiling

    2015-04-01

    Numerous people die of paraquat (PQ) poisoning because they were not diagnosed and treated promptly at an early stage. Till now, determination of PQ levels in blood or urine is still the only way to confirm the PQ poisoning. In order to develop a new diagnostic method, the potential of machine learning technique was explored in this study. A newly developed classification technique, extreme learning machine (ELM), was taken to discriminate the PQ-poisoned patients from the healthy controls. 15 PQ-poisoned patients recruited from The First Affiliated Hospital of Wenzhou Medical University who had a history of direct contact with PQ and 16 healthy volunteers were involved in the study. The ELM method is examined based on the metabolites of blood samples determined by gas chromatography coupled with mass spectrometry in terms of classification accuracy, sensitivity, specificity and AUC (area under the receiver operating characteristic (ROC) curve) criterion, respectively. Additionally, the feature selection was also investigated to further boost the performance of ELM and the most influential feature was detected. The experimental results demonstrate that the proposed approach can be regarded as a success with the excellent classification accuracy, AUC, sensitivity and specificity of 91.64%, 0.9156%, 91.33% and 91.78%, respectively. Promisingly, the proposed method might serve as a new candidate of powerful tools for diagnosis of PQ-poisoned patients with excellent performance. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Common Pesticides Used in Suicide Attempts Following the 2012 Paraquat Ban in Korea.

    Science.gov (United States)

    Lee, Jung-Won; Hwang, Il-Woong; Kim, Jae-Wook; Moon, Hyung-Jun; Kim, Ki-Hwan; Park, Suyeon; Gil, Hyo-Wook; Hong, Sae-Yong

    2015-10-01

    To determine the change in pesticides used during suicide attempts after the 2012 paraquat (PQ) ban, we evaluated the annual number of suicide attempts by pesticide ingestion between 2011 and 2014. We extracted demographic, clinical outcome, and pesticide class data from the medical records of 1,331 patients that attempted suicide by pesticide ingestion. Pesticides were sorted into 5 groups: herbicides, insecticides, fungicides, other pesticides, and combined pesticides. Each group was subdivided into various classes based on publications by the respective Resistance Action Committees. The chi-square test for trends was used to compare the annual incidence of categorical variables. The total number of suicide attempts decreased each year, from 399 in 2011 to 245 in 2014. Simultaneously, PQ ingestion decreased from 253 patients in 2011 to 60 in 2014. The proportion of PQ to pesticides also decreased from 63.4% in 2011 to 24.5% in 2014. Furthermore, the rate of decrease in the proportion of PQ to all herbicide categories increased by calendar year. In conclusion, there is a significant trend in increased annual number of suicides and proportion of suicides using glyphosates and glufosinates versus total herbicides. However, the number of suicide attempts using glyphosate and glufosinate is lower than that using PQ. The ratio of persons completing suicide to those attempting suicide after pesticide ingestion has decreased every year after the PQ ban.

  15. Hepatoprotective effect of Matricaria chamomilla.L in paraquat induced rat liver injury.

    Science.gov (United States)

    Tavakol, H S; Farzad, K; Fariba, M; Abdolkarim, C; Hassan, G; Seyed-Mostafa, H Z; Akram, R

    2015-02-01

    Paraquat (PQ), an effective and widely used herbicide, has been proven to be safe when appropriately applied to eliminate weeds. However, PQ poisoning is an extremely frustrating clinical condition with a high mortality and with a lack of effective treatments in humans. PQ is known to induce injury via a redox cyclic reaction. The purpose of this study was to investigate the effect of aqueous extract Matricaria chamomilla.L (M. chamomilla) against PQ-induced liver injury in association with its antioxidant activity.The male rats were treated by gastric gavage daily with PQ (5 mg/kg/day) and M. chamomilla (50 mg/kg/day) were administered alone or in combination for 7 days. After treatments, total antioxidant capacity (TAC), total thiol molecules (TTG) levels and catalase (CAT) activity in liver tissue were measured. At the end of the experiment, plasma and lung tissue of the animals was separated. The activity of enzymatic scavengers such as CAT, TAC and TTG were measured in liver homogenate.In this sample, the TAC and TTG were lower in the PQ group as compared with control group. Co-administration of PQ with M. chamomilla extract increased TAC and TTG in liver tissue as compared with PQ group.In conclusion, M. chamomilla as natural antioxidant may be considered beneficial for the protection oxidative liver injury in PQ poisoning. © Georg Thieme Verlag KG Stuttgart · New York.

  16. An intelligent prognostic system for analyzing patients with paraquat poisoning using arterial blood gas indexes.

    Science.gov (United States)

    Hu, Lufeng; Lin, Feiyan; Li, Huaizhong; Tong, Changfei; Pan, Zhifang; Li, Jun; Chen, Huiling

    The arterial blood gas (ABG) test is used to assess gas exchange in the lung, and the acid-base level in the blood. However, it is still unclear whether or not ABG test indexes correlate with paraquat (PQ) poisoning. This study investigates the predictive value of ABG tests in prognosing patients with PQ poisoning; it also identifies the most significant indexes of the ABG test. An intelligent machine learning-based system was established to effectively give prognostic analysis of patients with PQ poisoning based on ABG indexes. In the proposed system, an enhanced support vector machine combined with a feature selection strategy was developed to predict the risk status from a pool of 103 patients (56 males and 47 females); of these, 52 subjects were deceased and 51 patients were alive. The proposed method was rigorously evaluated against the real-life dataset in terms of accuracy, sensitivity, and specificity. Additionally, the feature selection was investigated to identify correlating factors for the risk status. The results demonstrated that there were significant differences in ABG indexes between deceased and alive subjects (p-value <0.01). According to the feature selection, we found that the most important correlated indexes were associated with partial pressure of carbon dioxide (PCO2). This study discovered the relationship between ABG test and poisoning degree to provide a new avenue for prognosing PQ poisoning. Copyright © 2016 Elsevier Inc. All rights reserved.

  17. Adsorption of paraquat on the physically activated bleaching earth waste from soybean oil processing plant.

    Science.gov (United States)

    Tsai, W T; Chen, C H; Yang, J M

    2002-09-01

    A series of regeneration experiments with physical activation were carried out on bleaching earth waste from the soybean refining process in a rotary reactor. The influence of activation parameters on the spent clay by varying the holding time of 1 to approximately 4 hours and temperature of 700 to approximately 900 degrees C was determined. The variations of pore properties as well as the change of chemical characteristics in the resulting solids were also studied. Results showed that the resulting samples were type IV with hysteresis loops corresponding to type H3 from nitrogen adsorption-desorption isotherms, indicating slit-shaped mesoporous characteristics. However, the regenerated clays had smaller surface areas (70 to approximately 117 m2/g) than that (245 m2/g) of fresh bleaching earth. Under the physical activation conditions investigated, the holding time of 1 hour and temperature of 700 degrees C were found to be optimal conditions for producing mesoporous clay with physical activation. The adsorption of paraquat on regenerated sample was also evaluated. The isotherm showed that the regenerated sample still had a high affinity for this herbicide. Thus, the regeneration of this agro-industrial waste is one option for utilizing the clay resource, and it may be used for water treatment applications to remove organic contaminants.

  18. Voltammetric Determination of Paraquat Using Graphite Pencil Electrode Modified with Doped Polypyrrole

    CERN Document Server

    Sayyahmanesh, Maryam; Meibodi, Azam S Emami; Ahooyi, Taha Mohseni

    2016-01-01

    Recognition and determination of paraquat (PQ) using graphite pencil electrode (GPE) modified with polypyrrole (Ppy) doped with Eriochrome blue-black B (EBB) is reported. To that end, a thin film of Ppy was deposited onto the electrode surface by electropolymerization in the presence of a functional doping ion, EBB. The Ppy/EBB-coated electrode was templated by PQ ion and then the performance of the molecularly imprinted EBB/Ppy/GPE was evaluated by voltammetric technique. The prepared electrode exhibited considerable increase in electroactivity of the sensor toward this herbicide compared to the non-imprinted electrode. To enhance the detection capability of the prepared system, the factors controlling its response were investigated and optimized using differential pulse voltammetry. The proposed analytical procedure was proved to be applicable in the concentration range of 5 to 50 {\\mu}M (R^2 = 0.9939) and detection limit of (3{\\sigma}) 0.22 {\\mu}M. Ultimately, the proposed analytical methodology was applie...

  19. Nrf2/ARE Pathway Involved in Oxidative Stress Induced by Paraquat in Human Neural Progenitor Cells

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    Tingting Dou

    2016-01-01

    Full Text Available Compelling evidences have shown that diverse environmental insults arising during early life can either directly lead to a reduction in the number of dopaminergic neurons or cause an increased susceptibility to neurons degeneration with subsequent environmental insults or with aging alone. Oxidative stress is considered the main effect of neurotoxins exposure. In this study, we investigated the oxidative stress effect of Paraquat (PQ on immortalized human embryonic neural progenitor cells by treating them with various concentrations of PQ. We show that PQ can decrease the activity of SOD and CAT but increase MDA and LDH level. Furthermore, the activities of Cyc and caspase-9 were found increased significantly at 10 μM of PQ treatment. The cytoplasmic Nrf2 protein expressions were upregulated at 10 μM but fell back at 100 μM. The nuclear Nrf2 protein expressions were upregulated as well as the downstream mRNA expressions of HO-1 and NQO1 in a dose-dependent manner. In addition, the proteins expression of PKC and CKII was also increased significantly even at 1 μM. The results suggested that Nrf2/ARE pathway is involved in mild to moderate PQ-induced oxidative stress which is evident from dampened Nrf2 activity and low expression of antioxidant genes in PQ induced oxidative damage.

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

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    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.

  1. Effect of humic acids on the adsorption of paraquat by goethite.

    Science.gov (United States)

    Brigante, Maximiliano; Zanini, Graciela; Avena, Marcelo

    2010-12-15

    The adsorption of the herbicide paraquat (PQ(2+)) on goethite and on the binary system humic acid-goethite has been studied in batch experiments by performing adsorption isotherms under different conditions of pH, supporting electrolyte concentration and temperature. The results were completed with capillary electrophoresis (CE) in order to measure the binding isotherm between PQ(2+) and humic acid (HA) molecules in solution. PQ(2+) adsorption is negligible on the bare goethite surface but important on the HA-goethite adsorbent. In this last case, the adsorption increases by increasing pH and decreasing electrolyte concentration. There are no significant effects of temperature on the adsorption. The adsorption takes place by direct binding of PQ(2+) to adsorbed HA molecules leading to the formation of surface species of the type goethite-HA-PQ(2+). The results are consistent with a mechanism where PQ(2+) binds negatively charged groups of HA (carboxylates and phenolates) forming ionic pairs or outer-sphere complexes. Since goethite in nature usually contains adsorbed HA molecules, it may act as a good adsorbent for cationic herbicides. This will not only benefit the deactivation of the herbicides but also reduce their leaching and transport through groundwater. Copyright © 2010 Elsevier B.V. All rights reserved.

  2. 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.

  3. Proteomic analysis of changes in protein expression in serum from animals exposed to paraquat.

    Science.gov (United States)

    Kim, Yong-Sik; Jung, Hana; Gil, Hyo-Wook; Hong, Sae-Yong; Song, Ho-Yeon

    2012-12-01

    Paraquat (PQ) poisoning remains a major public health concern in many countries. Extensive research has focused on finding early diagnostic biomarkers of acute PQ poisoning. In order to investigate the characterization of diagnostic biomarkers in PQ poisoning, we utilized proteomic analysis using serum from rats exposed to PQ, and we identified 8 differentially expressed proteins from over 500 protein spots. The expression of apolipoprotein E (ApoE), preprohaptoglobin (Pphg), a precursor of haptoglobin (Hp), and complement component 3 (C3) proteins was greatly induced by PQ exposure while the expression of fibrinogen γ-chain (FGG) and Ac-158 was dramatically reduced. To further investigate the possibility of ApoE, Pphg and FGG as useful diagnostic biomarkers of PQ poisoning, western blot and qRT-PCR analyses were conducted using cell lines as well as rat and human sera. The expression levels of ApoE, Hp and FGG were significantly altered in the presence of PQ in both rat and human serum suggesting that these proteins may be appropriate candidate molecular biomarkers for the early diagnosis of acute PQ intoxication.

  4. Beyond paraquats: dialkyl 3,3'- and 3,4'-bipyridinium amphiphiles as antibacterial agents.

    Science.gov (United States)

    Ator, Laura E; Jennings, Megan C; McGettigan, Amanda R; Paul, Jared J; Wuest, William M; Minbiole, Kevin P C

    2014-08-15

    Dialkyl 4,4'-bipyridinium compounds, known as 'paraquats' (PQs), have a long history of use as herbicides, as redox indicators, and more recently as potent antibacterial agents. However, due to their ability to form reactive oxygen species (ROS) in vivo, PQs are also known to be toxic. We proposed that altering the electrochemical properties of PQ, specifically by preparing isomeric bipyridinium structures with 3,3'- and 3,4'-substitution of the nitrogen heteroatoms on the biaryl core, would maintain antibacterial activity, yet decrease toxicity. We have thus prepared a series of 17 amphiphiles, dubbed 'metaquat' (MQ) and 'parametaquat' (PMQ), respectively, and investigated their antibacterial and electrochemical properties. Optimal inhibition of bacterial growth was observed in symmetric, biscationic structures; minimum inhibitory concentration (MIC) values measured as low as 0.5 μM against both Gram-positive and Gram-negative bacteria for the compound PMQ-11,11. Electrochemical analysis demonstrated the redox properties of the dialkyl 3,3'- and 3,4'-bipyridinium amphiphiles to be distinct from those of the 4,4'-bipyridinium isomer. Thus MQ and PMQ amphiphiles maintain the strong antibacterial activity of the PQ isomers, but show promise for reduced ROS toxicity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Ação de minhocas Eisenia foetida sobre a dissipação dos herbicidas simazina e paraquat aplicados no solo Action of earthworms Eisenia foetida on the dissipation of the herbicides simazine and paraquat applied onto soil

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    S. Papini

    2004-02-01

    Full Text Available Geralmente, os herbicidas são aplicados diretamente no solo, razão pela qual entram em contato direto com organismos deste ambiente, dentre eles as minhocas, as quais pelo metabolismo podem agir sobre resíduos desses compostos. Tomando minhocas da espécie Eisenia foetida como exemplo, determinaram-se a dissipação dos 14C-herbicidas (simazina e paraquat e a bioacumulação destes compostos em seus tecidos, a partir de solo tratado com as concentrações recomendadas e, no caso do paraquat, também com concentrações superiores. Solo e minhocas foram analisados por extração com solventes e técnicas radiométricas, após 30 ou 90 dias de contato. As minhocas alteraram a dissipação do simazina, visto que houve 100 % de recuperação do radiocarbono na ausência de minhocas e 90 % na presença dos animais. Além disso, elas acumularam resíduos e, ou, metabólitos de simazina em seus tecidos, tendo-se detectado Fator de Bioacumulação (FB de 1,45 e 1,17 após exposição ao solo tratado durante 30 e 90 dias, respectivamente. Por outro lado, a presença de minhocas não alterou o comportamento do herbicida paraquat aplicado ao solo, mas houve bioacumulação crescente de seus resíduos e, ou, metabólitos com o aumento da dose de tratamento (FB de 0,5; 3,2 e 5,5, respectivamente, nas concentrações recomendadas, 10 e 100 vezes superior.Herbicides are normally applied directly onto the soil, where they enter in contact with soil organisms, among these with earthworms, whose metabolism can act on herbicide residues. Focusing on the earthworms Eisenia foetida as model we determined: dissipation of the 14C- herbicides Simazine and Paraquat as well as bioaccumulation in the animal tissues from soil treated with the recommended doses and with 10 and 100 times higher doses for paraquat. Earthworms and soil were analyzed by solvent extraction and radiometric techniques after 30 or 90 days of contact. The earthworms altered the dissipation of

  6. Interferon-gamma deficiency modifies the motor and co-morbid behavioral pathology and neurochemical changes provoked by the pesticide paraquat.

    Science.gov (United States)

    Litteljohn, D; Mangano, E; Shukla, N; Hayley, S

    2009-12-29

    In addition to nigrostriatal pathology and corresponding motor disturbances, Parkinson's disease (PD) is often characterized by co-morbid neuropsychiatric symptoms, most notably anxiety and depression. Separate lines of evidence indicate that inflammatory processes associated with microglial activation and cytokine release may be fundamental to the progression of both PD and its co-morbid psychiatric pathology. Accordingly, we assessed the contribution of the pro-inflammatory cytokine, interferon-gamma (IFN-gamma), to a range of PD-like pathology provoked by the ecologically relevant herbicide and dopamine (DA) toxin, paraquat. To this end, paraquat provoked overt motor impairment (reduced home-cage activity and impaired vertical climbing) and signs of anxiety-like behavior (reduced open field exploration) in wild-type but not IFN-gamma-deficient mice. Correspondingly, paraquat promoted somewhat divergent variations in neurochemical activity among wild-type and IFN-gamma null mice at brain sites important for both motor (striatum) and co-morbid affective pathologies (dorsal hippocampus, medial prefrontal cortex, and locus coeruleus). Specifically, the herbicide provoked a dosing regimen-dependent reduction in striatal DA levels that was prevented by IFN-gamma deficiency. In addition, the herbicide influenced serotonergic and noradrenergic activity within the dorsal hippocampus and medial prefrontal cortex; and elevated noradrenergic activity within the locus coeruleus. Although genetic ablation of IFN-gamma had relatively few effects on monoamine variations within the locus coeruleus and prefrontal cortex, loss of the pro-inflammatory cytokine did normalize the paraquat-induced noradrenergic alterations within the hippocampus. These findings further elucidate the functional implications of paraquat intoxication and suggest an important role for IFN-gamma in the striatal and motor pathology, as well as the co-morbid behavioral and hippocampal changes induced by

  7. Enhanced tolerance to methyl viologen-induced oxidative stress and high temperature in transgenic potato plants overexpressing the CuZnSOD, APX and NDPK2 genes.

    Science.gov (United States)

    Kim, Myoung Duck; Kim, Yun-Hee; Kwon, Suk-Yoon; Yun, Dae-Jin; Kwak, Sang-Soo; Lee, Haeng-Soon

    2010-10-01

    Oxidative stress is a major threat for plants exposed to various environmental stresses. Previous studies found that transgenic potato plants expressing both copper zinc superoxide dismutase (CuZnSOD) and ascorbate peroxidase (APX) (referred to as SSA plants), or nucleoside diphosphate kinase 2 (NDPK2) (SN plants), showed enhanced tolerance to methyl viologen (MV)-induced oxidative stress and high temperature. This study aimed to develop transgenic plants that were more tolerant of oxidative stress by introducing the NDPK2 gene into SSA potato plants under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter to create SSAN plants. SSAN leaf discs and whole plants showed enhanced tolerance to MV, as compared to SSA, SN or non-transgenic (NT) plants. SSAN plants sprayed with 400 µM MV exhibited about 53 and 83% less visible damage than did SSA and SN plants, respectively. The expression levels of the CuZnSOD, APX and NDPK2 genes in SSAN plants following MV treatment correlated well with MV tolerance. SOD, APX, NDPK and catalase antioxidant enzyme activities were also increased in MV-treated SSAN plants. In addition, SSAN plants were more tolerant to high temperature stress at 42°C, exhibiting a 6.2% reduction in photosynthetic activity as compared to plants grown at 25°C. In contrast, the photosynthetic activities of SN and SSA plants decreased by 50 and 18%, respectively. These results indicate that the simultaneous overexpression of CuZnSOD, APX and NDPK2 is more effective than single or double transgene expression for developing plants with enhanced tolerance to various environmental stresses. Copyright © Physiologia Plantarum 2010.

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

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    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.

  9. Effects of hemoperfusion and continuous renal replacement therapy on patient survival following paraquat poisoning.

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    Yadong Wang

    Full Text Available Mortality in patients with paraquat (PQ poisoning is related to plasma PQ levels. Concentrations lower than 5,000 ng/mL are considered critical but curable. This study assessed the effects of hemoperfusion (HP and continuous renal replacement therapy (CRRT on the survival of PQ-poisoned patients with plasma PQ levels below 5,000ng/mL. We analyzed the records of 164 patients with PQ poisoning who were treated at the First Affiliated Hospital of Wenzhou Medical University in China between January 2011 and May 2015. We divided these patients into six sub-groups based on baseline plasma PQ levels and treatment, compared their clinical characteristics, and analyzed their survival rates. Patient sub-groups did not differ in terms of age, sex, time between poisoning and hospital admission, or time to first gavage. Biochemical indicators improved over time in all sub-groups following treatment, and the combined HP and CRRT treatment yielded better results than HP or CRRT alone. Fatality rates in the three treatment sub-groups did not differ among patients with baseline plasma PQ levels of 50-1,000 ng/mL, but in patients with 1,000-5,000 ng/mL levels, the mortality rate was 59.2% (HP treatment group, 48% (CRRT treatment group, and 37.9% (combined treatment group. Mortality rates were higher 10-30 days after hospitalization than in the first 10 days after admission. In the early stages of PQ poisoning, CRRT is effective in reducing patient fatality rates, particularly when combined with HP. Our data could be useful in increasing survival in acute PQ poisoning patients.

  10. Effects of hemoperfusion and continuous renal replacement therapy on patient survival following paraquat poisoning

    Science.gov (United States)

    Wang, Yadong; Chen, Yao; Mao, Lu; Zhao, Guangju; Hong, Guangliang; Li, Mengfang; Wu, Bin; Chen, Xiaorong; Tan, Meng; Wang, Na

    2017-01-01

    Mortality in patients with paraquat (PQ) poisoning is related to plasma PQ levels. Concentrations lower than 5,000 ng/mL are considered critical but curable. This study assessed the effects of hemoperfusion (HP) and continuous renal replacement therapy (CRRT) on the survival of PQ-poisoned patients with plasma PQ levels below 5,000ng/mL. We analyzed the records of 164 patients with PQ poisoning who were treated at the First Affiliated Hospital of Wenzhou Medical University in China between January 2011 and May 2015. We divided these patients into six sub-groups based on baseline plasma PQ levels and treatment, compared their clinical characteristics, and analyzed their survival rates. Patient sub-groups did not differ in terms of age, sex, time between poisoning and hospital admission, or time to first gavage. Biochemical indicators improved over time in all sub-groups following treatment, and the combined HP and CRRT treatment yielded better results than HP or CRRT alone. Fatality rates in the three treatment sub-groups did not differ among patients with baseline plasma PQ levels of 50–1,000 ng/mL, but in patients with 1,000–5,000 ng/mL levels, the mortality rate was 59.2% (HP treatment group), 48% (CRRT treatment group), and 37.9% (combined treatment group). Mortality rates were higher 10–30 days after hospitalization than in the first 10 days after admission. In the early stages of PQ poisoning, CRRT is effective in reducing patient fatality rates, particularly when combined with HP. Our data could be useful in increasing survival in acute PQ poisoning patients. PMID:28704509

  11. Melatonin inhibits paraquat-induced cell death in bovine preimplantation embryos.

    Science.gov (United States)

    Pang, Yun-Wei; Sun, Ye-Qing; Sun, Wei-Jun; Du, Wei-Hua; Hao, Hai-Sheng; Zhao, Shan-Jiang; Zhu, Hua-Bin

    2016-03-01

    Preimplantation embryos are sensitive to oxidative stress-induced damage that can be caused by reactive oxygen species (ROS) originating from normal embryonic metabolism and/or the external surroundings. Paraquat (PQ), a commonly used pesticide and potent ROS generator, can induce embryotoxicity. The present study aimed to investigate the effects of melatonin on PQ-induced damage during embryonic development in bovine preimplantation embryos. PQ treatment significantly reduced the ability of bovine embryos to develop to the blastocyst stage, and the addition of melatonin markedly reversed the developmental failure caused by PQ (20.9% versus 14.3%). Apoptotic assay showed that melatonin pretreatment did not change the total cell number in blastocysts, but the incidence of apoptotic nuclei and the release of cytochrome c were significantly decreased. Using real-time quantitative polymerase chain reaction analysis, we found that melatonin pre-incubation significantly altered the expression levels of genes associated with redox signaling, particularly by attenuating the transcript level of Txnip and reinforcing the expression of Trx. Furthermore, melatonin pretreatment significantly reduced the expression of the pro-apoptotic caspase-3 and Bax, while the expression of the anti-apoptotic Bcl-2 and XIAP was unaffected. Western blot analysis showed that melatonin protected bovine embryos from PQ-induced damage in a p38-dependent manner, but extracellular signal-regulated kinase (ERK) and c-JUN N-terminal kinase (JNK) did not appear to be involved. Together, these results identify an underlying mechanism by which melatonin enhances the developmental potential of bovine preimplantation embryos under oxidative stress conditions. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. 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.

  13. 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.

  14. 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.

  15. Salidroside alleviates paraquat-induced rat acute lung injury by repressing TGF-β1 expression

    Science.gov (United States)

    Zhang, Zhuoyi; Ding, Limin; Wu, Liqun; Xu, Liying; Zheng, Lanzhi; Huang, Xiaomin

    2014-01-01

    Objective: This study was designed to investigate the protective effects of salidroside (SDS) via suppressing the expression of transforming growth factor-β1 (TGF-β1) in rat acute lung injury (ALI) induced by paraquat (PQ) and to explore the potential molecular mechanisms. Methods: A total of 90 male rats (190-210 g) were randomly and evenly divided into 9 groups: control group, PQ groups (4 groups), and PQ + SDS groups (4 groups). The rats in control group were treated with equal volume of saline intraperitoneally. The rats in PQ groups were exposed to PQ solution (20 mg/kg) by gastric gavage for 1, 6, 24, and 72 hours, respectively. The rats in PQ + SDS groups were intraperitoneally injected once with SDS (10 mg/kg) every 12 hours after PQ perfusion. Pulmonary pathological changes were observed by hematoxylin and eosin (HE) staining. The expression of TGF-β1 and the mRNA were evaluated by immunohistochemical (IHC) scoring and real time quantitative reverse transcription polymerase chain reaction (real-time qRT-PCR), respectively. Results: SDS alleviated the symptoms of PQ induced ALI. Moreover, SDS reduced the expression of the inflammatory cytokine TGF-β1 including TGF-β1 IHC scores (at each time point from 6 to 72 hours after PQ perfusion) and mRNA level (at each time point from 1 to 72 hours after PQ perfusion) compared with PQ groups (P < 0.05). Conclusion: SDS alleviated the pulmonary symptoms of PQ-induced ALI, at least partially, by repressing inflammatory cell infiltration and the expression of TGF-β1 resulting in delayed lung fibrosis. PMID:25674253

  16. Transport of paraquat by human organic cation transporters and multidrug and toxic compound extrusion family.

    Science.gov (United States)

    Chen, Ying; Zhang, Shuzhong; Sorani, Marco; Giacomini, Kathleen M

    2007-08-01

    Paraquat (N,N-dimethyl-4-4'-bipiridinium; PQ), a widely used herbicide, when ingested accidentally or intentionally can cause major organ toxicities in lung, liver, and kidney. Because PQ is primarily eliminated in the kidney, renal elimination, including tubular transport, plays a critical role in controlling systemic exposure to the herbicide. The goal of this study was to determine the molecular identities of the transporters involved in the renal elimination of PQ. Using stably transfected human embryonic kidney (HEK)-293 cells, we examined the role of human organic cation transporters (hOCTs, SLC22A1-3) and human multidrug and toxic compound extrusion (hMATE)1 in the cellular accumulation and cytotoxicity of PQ. We found that overexpression of hOCT2 but not hOCT1 and hOCT3 in HEK-293 cells significantly enhanced the accumulation and cytotoxicity of PQ (-fold increase for uptake was 12 +/- 0.5, p < 0.01; -fold increase of cytotoxicity was 18 +/- 1.5, p < 0.001). The kinetics of PQ transport was altered in cells expressing a genetic polymorphism of hOCT2 (A270S) in comparison with those expressing the reference hOCT2. In addition, the cellular accumulation and cytotoxicity of PQ were also enhanced in cells expressing hMATE1 (-fold increase for uptake was 18 +/- 3.7, p < 0.0001; -fold increase of cytotoxicity was 5.7 +/- 0.5, p < 0.0001). These results suggest that hOCT2 and hMATE1 mediate PQ transport. These transporters may play an important role in the accumulation and renal excretion of PQ, and they may serve as molecular targets for the prevention and treatment of PQ-induced nephrotoxicity.

  17. Development and independent laboratory validation of a simple method for the determination of paraquat and diquat in potato, cereals and pulses

    NARCIS (Netherlands)

    Kolberg, D.I.S.; Mack, D.; Anastassiades, M.; Hetmanski, M.T.; Fussell, R.J.; Meijer, T.; Mol, J.G.J.

    2012-01-01

    A new sensitive, fast and robust method for the determination of paraquat and diquat residues in potatoes, cereals and pulses is presented. Different extraction conditions (solvent, time and temperature) have been evaluated using barley grain, potatoes and dry lentils containing incurred residues of

  18. 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

  19. Protective action of Omega-3 on paraquat intoxication in Drosophila melanogaster.

    Science.gov (United States)

    de Oliveira Souza, Anderson; Couto-Lima, Carlos Antônio; Rosa Machado, Maiaro Cabral; Espreafico, Enilza Maria; Pinheiro Ramos, Ricardo Guelerman; Alberici, Luciane Carla

    2017-01-01

    Paraquat (PQ) (1,1'-dimethyl-4-4'-bipyridinium dichloride) is the second most widely used herbicide worldwide; however, in countries different sales and distribution remain restricted. Chronic exposure to PQ leads to several diseases related to oxidative stress and mitochondrial dysfunctions including myocardial failure, cancer, and neurodegeneration and subsequently death depending upon the dose level. The aim of this study was to examine if diet supplementation with eicosapentaenoic and docosahexaenoic acids (EPA and DHA, omega-3 long-chain fatty acids) serves a protective mechanism against neuromuscular dysfunctions mediated by PQ using Drosophila melanogaster as a model with focus on mitochondrial metabolism. PQ ingestion (170 mg/kg b.w. for 3 d) resulted in a decreased life span and climbing ability in D. melanogaster. In the brain, PQ increased thioflavin fluorescence and reduced either 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) nuclei staining and neuronal nuclei protein (NeuN) positive neurons, indicating amyloid formation and neurodegenetation, respectively. In the thorax, PQ ingestion lowered citrate synthase activity and respiratory functions indicating a reduction in mitochondrial content. PQ elevated Ca2+/calmodulin-dependent protein kinase II (CaMKII) mRNA expression levels, indicative of high calcium influx from cytosol to mitochondrial matrix. In brain and thorax, PQ also increased hydrogen peroxide (H2O2) production and impaired acetylcholinesterase (AChE) activity. Concomitant EPA/DHA ingestion (0.31/0.19 mg/kg b.w.) protected D. melanogaster against PQ-induced toxicity preserving neuromuscular function and slowing down the rate of aging. In brain and thorax, these omega-3 fatty acids inhibited excess H2O2 production and restored AChE activity. EPA/DHA delayed amyloid deposition in the brain, and restored low citrate synthase activity and respiratory functions in the thorax. The effects in the thorax were attributed to stimulated m

  20. 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

  1. Silver particles-modified carbon paste electrodes for differential pulse voltammetric determination of paraquat in ambient water samples

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    A. Farahi

    2016-02-01

    Full Text Available This paper describes the construction of silver particles-impregnated carbon paste electrode (Ag-CPE. The new electrode revealed an interesting determination of paraquat (II. The latter was accumulated on the modified electrode surface by adsorption onto silver particles and was reduced in 0.1 mol L−1 of Na2SO4 electrolyte at −0.70 V and −1.0 V for peaks 1 and 2, respectively. Experimental conditions were optimized by varying the heating temperature of the silver/carbon composite, the Ag/CP ratio, pH of measuring solution and accumulation time. Under the optimized working conditions, calibration graphs were linear for the concentration ranging from 1.0 × 10−7 to 1.0 × 10−3 mol L−1 with detection limits (DL, 3σ 3.3 and 6.4 × 10−9 mol L−1, respectively, for peaks 1 and 2. The precision of this methodology was evaluated for eight successive measurements of the same samples containing 1.0 × 10−4 mol L−1 of paraquat. The relative standard deviations (D.S.R. were 1.9% and 2.4% for the peaks 1 and 2, respectively. The Ag/CP composite was characterized by X-ray diffraction (XRD and BET adsorption analysis.

  2. A Dual-Thermoresponsive Gemini-Type Supra-amphiphilic Macromolecular [3]Pseudorotaxane Based on Pillar[10]arene/Paraquat Cooperative Complexation.

    Science.gov (United States)

    Chi, Xiaodong; Yu, Guocan; Shao, Li; Chen, Jianzhuang; Huang, Feihe

    2016-03-09

    Herein, first we report the preparation of a thermoresponsive [3]pseudorotaxane from cooperative complexation between a water-soluble pillar[10]arene and a paraquat derivative in water. Then we successfully construct the first pillararene-based gemini-type supra-amphiphilic [3]pseudorotaxane from the water-soluble pillar[10]arene and a paraquat-containing poly(N-isopropylacrylamide) based on this new molecular recognition motif in water. This macromolecular [3]pseudorotaxane shows unique dual-thermoresponsiveness. Furthermore, it can self-assemble into polymeric vesicles at 37 °C in water. These vesicles can be further used in the controlled release of small molecules induced by cooling to 25 °C or heating to 60 °C.

  3. Quantification of Paraquat, MPTP, and MPP+ in brain tissue using microwave-assisted solvent extraction (MASE) and high performance liquid chromatography-mass spectrometry

    OpenAIRE

    Winnik, Bozena; Barr, Dana B.; Thiruchelvam, Mona; Montesano, M. Angela; Richfield, Eric K.; Buckley, Brian

    2009-01-01

    Animal models, consistent with the hypothesis of direct interaction of paraquat (PQ) and 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) with specific areas of the central nervous system have been developed to study Parkinson’s disease (PD) in mice. These models have necessitated the creation of an analytical method for unambiguous identification and quantitation of PQ and structurally similar MPTP and 1-Methyl-4-phenylpyridinium ion (MPP+) in brain tissue. A method for determination of t...

  4. 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

  5. Magnetic Solid-Phase Extraction Using Fe3O4@SiO2 Magnetic Nanoparticles Followed by UV-Vis Spectrometry for Determination of Paraquat in Plasma and Urine Samples

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    Ou Sha

    2017-01-01

    Full Text Available A rapid and simple method was optimized and validated for the separation and quantification of paraquat, a frequently used herbicide and a leading cause of fatal poisoning worldwide, at trace levels with UV-Vis spectrophotometry in plasma and urine samples by direct magnetic solid-phase extraction. Fe3O4@SiO2 nanoparticles (NPs were used as the magnetic solid-phase extraction agents and the paraquat absorbed on NPs was eluted using NaOH and ascorbic acid. Upon optimization, paraquat could be extracted and concentrated from various samples by 35-fold. The linear range, limit of detection (LOD, correlation coefficient (R, and relative standard deviation (RSD could reach 15.0–400.0 μg/L, 12.2 μg/L, 0.9987, and 0.65% (n=5, c = 40.0 μg/L, respectively. The Fe3O4@SiO2 NPs could be reused up to five times. The method was successfully applied to the determination of paraquat in urine and plasma at different hemoperfusion numbers in a local hospital for the patient of paraquat poisoning. The experiment result could not only enable immediate medical intervention but also benefit patients’ survival.

  6. Heterologous expression of predicted promoter site for paraquat-inducible genes of the bacterium Chromobacterium violaceum is increased by plumbagin

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    Jane Eyre Gabriel

    2017-05-01

    Full Text Available The aim of this study was to evaluate functionally the effect of plumbagin on the heterologous expression of a predicted promoter region of open reading frames of paraquat-inducible (pqi genes revealed during genome annotation analyses of the bacterium Chromobacterium violaceum. First, the promoter of interest was amplified using specific primers and cloned into a conjugative vector carrying the Escherichia coli lacZ gene without a promoter. The heterologous expression of the predicted promoter region was then examined in the presence of 50 µg/mL plumbagin by β-galactosidase expression assays. Significant differences were detected in the levels of β-galactosidase as a result of the activation of the promoter region of interest in response to plumbagin at the concentration tested. On the other hand, no growth of the wild strain of C. violaceum was found during its incubation in nutrient broth medium containing different concentrations of plumbagin compared to control group. The findings described herein demonstrate that the heterologous expression of a predicted promoter site of pqi genes of C. violaceum is induced by plumbagin in a fusion strain, giving insights into the functional characterization of intrinsic regulatory DNA motifs annotated in this bacterial genome.

  7. Heterologous expression of predicted promoter site for paraquat-inducible genes of the bacterium Chromobacterium violaceum is increased by plumbagin

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    Jane Eyre Gabriel

    2017-05-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2017v30n2p1 The aim of this study was to evaluate functionally the effect of plumbagin on the heterologous expression of a predicted promoter region of open reading frames of paraquat-inducible (pqi genes revealed during genome annotation analyses of the bacterium Chromobacterium violaceum. First, the promoter of interest was amplified using specific primers and cloned into a conjugative vector carrying the Escherichia coli lacZ gene without a promoter. The heterologous expression of the predicted promoter region was then examined in the presence of 50 µg/mL plumbagin by β-galactosidase expression assays. Significant differences were detected in the levels of β-galactosidase as a result of the activation of the promoter region of interest in response to plumbagin at the concentration tested. On the other hand, no growth of the wild strain of C. violaceum was found during its incubation in nutrient broth medium containing different concentrations of plumbagin compared to control group. The findings described herein demonstrate that the heterologous expression of a predicted promoter site of pqi genes of C. violaceum is induced by plumbagin in a fusion strain, giving insights into the functional characterization of intrinsic regulatory DNA motifs annotated in this bacterial genome.

  8. 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.

  9. 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.

  10. 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.

  11. Leaf Age-Dependent Photoprotective and Antioxidative Response Mechanisms to Paraquat-Induced Oxidative Stress in Arabidopsis thaliana

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    Julietta Moustaka

    2015-06-01

    Full Text Available Exposure of Arabidopsis thaliana young and mature leaves to the herbicide paraquat (Pq resulted in a localized increase of hydrogen peroxide (H2O2 in the leaf veins and the neighboring mesophyll cells, but this increase was not similar in the two leaf types. Increased H2O2 production was concomitant with closed reaction centers (qP. Thirty min after Pq exposure despite the induction of the photoprotective mechanism of non-photochemical quenching (NPQ in mature leaves, H2O2 production was lower in young leaves mainly due to the higher increase activity of ascorbate peroxidase (APX. Later, 60 min after Pq exposure, the total antioxidant capacity of young leaves was not sufficient to scavenge the excess reactive oxygen species (ROS that were formed, and thus, a higher H2O2 accumulation in young leaves occurred. The energy allocation of absorbed light in photosystem II (PSII suggests the existence of a differential photoprotective regulatory mechanism in the two leaf types to the time-course Pq exposure accompanied by differential antioxidant protection mechanisms. It is concluded that tolerance to Pq-induced oxidative stress is related to the redox state of quinone A (QA.

  12. Ilex paraguariensis Extract Increases Lifespan and Protects Against the Toxic Effects Caused by Paraquat in Caenorhabditis elegans

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    Maria E. Lima

    2014-09-01

    Full Text Available Recent studies have shown that phenolic compounds present in yerba mate have antioxidant defense properties. To verify whether Ilex paraguariensis extracts are capable of increasing the lifespan of an organism, we have used the free-living nematode Caenorhabditis elegans. Notably, this is the first study that analyzes the effects of the extracts of yerba mate obtained from an extraction method that mimics the manner that the plant is consumed by the population by using a live organism. Yerba mate was purchased from commercial markets from Argentina, Brazil, and Uruguay. Ilex paraguariensis extracts significantly increased the life span of C. elegans. Moreover, the extracts reduced the ROS levels per se, and protected from the reduced survival and reproduction rate induced by paraquat exposure. Considering molecular aspects, we observed that the worms pretreated with the extracts depicted higher translocation of the transcription factor DAF-16::GFP to the nucleus. However, there was no increase in the levels of the DAF-16 target genes, SOD-3 and catalase. Our results suggest that the increase of lifespan caused by the different extracts is associated to the antioxidant potential of yerba mate, however this effect is not completely mediated by daf-16.

  13. Identification of apoptosis and macrophage migration events in paraquat-induced oxidative stress using a zebrafish model.

    Science.gov (United States)

    Wang, Qiang; Liu, Shuai; Hu, Dayong; Wang, Zhen; Wang, Ling; Wu, Tianfu; Wu, Zhuanbin; Mohan, Chandra; Peng, Ai

    2016-07-15

    Paraquat (PQ) is a pesticide highly toxic to human beings, and a well-known trigger of oxidative stress. Although several animal models of PQ poisoning have been developed, some disadvantages limit their application in vivo. A zebrafish model was used in the present study to better define mechanisms of oxidative stress injury induced by PQ. The toxicity of PQ was evaluated in the AB strain of zebrafish, and apoptosis was assessed by acridine orange staining. Macrophage migration was identified using the TG (zlyz:EGFP) transgenic strain, and angiogenesis was observed using the fli1a-EGFP casper strain. Following the validation of gene changes by zebrafish-based in vivo quantitative real-time PCR, network analysis was performed using the Ingenuity Pathway Analysis software. We first established the LC50 of PQ in the zebrafish model, and then found that robust oxidative stress and antioxidant genes were activated after PQ exposure. Moreover, apoptosis and distinct macrophage activation and migration were identified for the first time in PQ-exposed zebrafish. Utilizing this model, both extrinsic and intrinsic pathways involved in PQ-induced apoptosis were elucidated. We further demonstrated that macrophage migration was specifically induced by PQ, and that Rho family members and JNK-MMP13 signaling participated in this process. Zebrafish is a promising tool for investigating the mechanisms of oxidative stress injury induced by PQ, and for screening effective anti-oxidant drugs. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Development of an integrated chemical process system for utilization of complete Paraquat-treated pine trees. Final report, 1 July 1977-31 March 1979

    Energy Technology Data Exchange (ETDEWEB)

    O' Neil, D.J.; Bery, M.K.; El-Barbary, I.A.; Kovac, R.J.

    1979-01-01

    In 1973 it was reported that the treatment of southern pine trees with the herbicide Paraquat could induce lightwood formation with very significant increases in the extractable oleoresins and turpentine fractions. The objectives of this project included the characterization of this phenomenon, development of realistic qualitative and quantitative data on the extent of lightwood formation and the recovery of oleoresin and turpentine fractions. The principal objective was to determine if the yields of oleoresinous products and turpentine justified a stand-alone, economic wood extraction process technology, based on the utilization of whole- or complete-Paraquat-treated pine trees. The application of this technology was considered to be appropriate as a sub-system of an integrated chemical process system wherein ethanol, lignin (or hydrocarbon derivatives), and sugars would be manufactured as co-products. Alternately, such extraction technology could be used as a pre-treatment operation prior to Kraft pulping processing. Yield results tended to be variable. Turpentine increases ranged from 2- to 4-fold on a merchantable bole basis with increases at the site of injection as high as 12-fold. The distribution of the turpentine content in Paraquat-treated trees, as well as for extractives content, decreased to normal background levels at about six feet above the wound site. Oleoresin content increases normally ranged from 2 to 3 fold with a maximum total extractables content (or yield) of about 8% on a dry weight basis. Under current conditions, the phenomenon of lightwood formation in mature trees may best be exploited in pulp process plants.

  15. 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.

  16. 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.

  17. Maneb and paraquat-induced modulation of toxicant responsive genes in the rat liver: comparison with polymorphonuclear leukocytes.

    Science.gov (United States)

    Ahmad, Israr; Shukla, Smriti; Kumar, Ashutosh; Singh, Brajesh Kumar; Patel, Devendra Kumar; Pandey, Haushila Prasad; Singh, Chetna

    2010-12-05

    Experimental studies have shown that toxicant responsive genes, cytochrome P450s (CYPs) and glutathione S-transferases (GSTs) play a critical role in pesticide-induced toxicity. CYPs play pro-oxidant role and GSTs offer protection in maneb (MB) and paraquat (PQ)-induced brain and lung toxicities. The present study aimed to investigate the effect of repeated exposures of MB and/or PQ on lipid peroxidation (LPO), glutathione content (GSH) and toxicant responsive genes, i.e., CYP1A1, 1A2, 2E1, GSTA4-4, GSTA1-1 and GSTA3-3 in the liver and to correlate the same with polymorphonuclear leukocytes (PMNs). A significant augmentation in LPO and reduction in GSH content was observed in a time of exposure dependent manner in the liver and PMNs of MB and/or PQ treated animals. The expression and catalytic activity of CYP2E1 and GSTA4-4 were significantly increased following MB and/or PQ exposure both in the liver and PMNs. Although the expression of GSTA3-3 was increased, the expression of GSTA1-1 was unaltered after MB and/or PQ treatment in both the liver and PMNs. MB augmented the expression and catalytic activity of CYP1A1 in the liver, however, CYP1A2 was unaffected. PQ, on the other hand, significantly increased hepatic CYP1A2 expression and catalytic activity. MB and/or PQ did not produce any significant changes in CYP1A1 and CYP1A2 in PMNs. The results of the study thus demonstrate that MB and PQ differentially regulate hepatic CYP1A1 and CYP1A2 while LPO, GSH, CYP2E1, GSTA4-4 and GSTA3-3 are modulated in the similar fashions both in the liver and PMNs. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  18. Low ergosterol content in yeast adh1 mutant enhances chitin maldistribution and sensitivity to paraquat-induced oxidative stress.

    Science.gov (United States)

    Marisco, G; Saito, S T; Ganda, I S; Brendel, M; Pungartnik, C

    2011-05-01

    Alcohol dehydrogenases catalyse the reversible oxidation of alcohols to aldehydes or ketones, with concomitant reduction of NAD(+) or NADP(+) . Adh1p is responsible for the reduction of acetaldehyde to ethanol, while Adh2p catalyses the reverse reaction, the oxidation of ethanol to acetaldehyde. Lack of Adh1p shifts the cellular redox balance towards excess NADH/NADPH and acetaldehyde, while absence of Adh2p does the opposite. Yeast mutant adh1Δ had a slow growth rate, whereas adh2Δ grew like the isogenic wild-type (WT) during prediauxic shift fermentative metabolism. After 48 h WT and mutants reached the same number of viable cells. When exponentially growing (LOG) cells were exposed to calcofluor white, only mutant adh1Δ displayed an irregular deposition of chitin. Quantitative analyses of both LOG and stationary-phase cells showed that adh1Δ mutant contained significantly less ergosterol than cells of WT and adh2Δ mutant, whereas the erg3Δ mutant contained extremely low ergosterol pools. Both adh1Δ and adh2Δ mutants showed higher-than-WT resistance to heat shock and to H(2) O(2) but had WT resistance when exposed to ultraviolet (UV) light and the DNA cross-linking agent diepoxyoctane, indicating normal DNA repair capacity. Mutant adh1Δ was specifically sensitive to acetaldehyde and to membrane peroxidizing paraquat. Our results link the pleiotropic phenotype of adh1Δ mutants to low pools of ergosterol and to reductive stress, and introduce the two new phenotypes, resistance to heat shock and to H(2) O(2) , for the adh2Δ mutant, most probably related to increased ROS production in mitochondria, which leads to the induction of oxidative stress protection. Copyright © 2011 John Wiley & Sons, Ltd.

  19. Epigallocatechin-3-gallate alleviates paraquat-induced acute lung injury and inhibits upregulation of toll-like receptors.

    Science.gov (United States)

    Shen, Haitao; Wu, Na; Liu, Zhenning; Zhao, Hongyu; Zhao, Min

    2017-02-01

    To evaluate the detoxifying effect of epigallocatechin-3-gallate (EGCG) on paraquat (PQ)-induced acute lung injury in mice, and to explore the action mechanisms. Following administration of PQ, the mice received a low, a medium or a high dose of EGCG daily for three days. Histopathology of the lungs were examined by H&E staining. The levels of inflammatory cytokines, such as TNF-α, IL-1β and IL-6, in the bronchoalveolar lavage fluid were measured by enzyme-linked immunosorbent assay. Activation of NF-κB was assessed by Western blot and electrophoretic mobility gel shift assay. The expression of toll-like receptor (TLR)-2, 4, 9 and TLR adaptors (MyD88 and TRAF6) was detected by Western blot and immunohistochemical staining. The protective effect of EGCG against PQ toxicity was validated in vitro using A549 lung cancer cell line. Treatment with EGCG dose-dependently attenuated PQ-induced acute lung injury in mice by reducing alveolar edema, hemorrhage, inflammatory cell infiltration and production of inflammatory cytokines. EGCG inhibited the activation of NF-κB and the upregulation of TLR 2, 4 and 9 as well as their adaptors MyD88 and TRAF6 in the lungs following PQ challenge. In addition, EGCG significantly reduced PQ-induced cell death, cytokine production, activation of NF-κB, and upregulation of TLRs and adaptors in A549 cells. Our data suggest that TLR-mediated activation of NF-κB in the non-immune pulmonary cells could be involved in PQ-induced acute lung injury, and it may serve as a target of EGCG against PQ pulmonary toxicity. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. A new machine-learning method to prognosticate paraquat poisoned patients by combining coagulation, liver, and kidney indices.

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    Lufeng Hu

    Full Text Available The prognosis of paraquat (PQ poisoning is highly correlated to plasma PQ concentration, which has been identified as the most important index in PQ poisoning. This study investigated the predictive value of coagulation, liver, and kidney indices in prognosticating PQ-poisoning patients, when aligned with plasma PQ concentrations. Coagulation, liver, and kidney indices were first analyzed by variance analysis, receiver operating characteristic curves, and Fisher discriminant analysis. Then, a new, intelligent, machine learning-based system was established to effectively provide prognostic analysis of PQ-poisoning patients based on a combination of the aforementioned indices. In the proposed system, an enhanced extreme learning machine wrapped with a grey wolf-optimization strategy was developed to predict the risk status from a pool of 103 patients (56 males and 47 females; of these, 52 subjects were deceased and 51 alive. The proposed method was rigorously evaluated against this real-life dataset, in terms of accuracy, Matthews correlation coefficients, sensitivity, and specificity. Additionally, the feature selection was investigated to identify correlating factors for risk status. The results demonstrated that there were significant differences in the coagulation, liver, and kidney indices between deceased and surviving subjects (p<0.05. Aspartate aminotransferase, prothrombin time, prothrombin activity, total bilirubin, direct bilirubin, indirect bilirubin, alanine aminotransferase, urea nitrogen, and creatinine were the most highly correlated indices in PQ poisoning and showed statistical significance (p<0.05 in predicting PQ-poisoning prognoses. According to the feature selection, the most important correlated indices were found to be associated with aspartate aminotransferase, the aspartate aminotransferase to alanine ratio, creatinine, prothrombin time, and prothrombin activity. The method proposed here showed excellent results that were

  1. A new machine-learning method to prognosticate paraquat poisoned patients by combining coagulation, liver, and kidney indices.

    Science.gov (United States)

    Hu, Lufeng; Li, Huaizhong; Cai, Zhennao; Lin, Feiyan; Hong, Guangliang; Chen, Huiling; Lu, Zhongqiu

    2017-01-01

    The prognosis of paraquat (PQ) poisoning is highly correlated to plasma PQ concentration, which has been identified as the most important index in PQ poisoning. This study investigated the predictive value of coagulation, liver, and kidney indices in prognosticating PQ-poisoning patients, when aligned with plasma PQ concentrations. Coagulation, liver, and kidney indices were first analyzed by variance analysis, receiver operating characteristic curves, and Fisher discriminant analysis. Then, a new, intelligent, machine learning-based system was established to effectively provide prognostic analysis of PQ-poisoning patients based on a combination of the aforementioned indices. In the proposed system, an enhanced extreme learning machine wrapped with a grey wolf-optimization strategy was developed to predict the risk status from a pool of 103 patients (56 males and 47 females); of these, 52 subjects were deceased and 51 alive. The proposed method was rigorously evaluated against this real-life dataset, in terms of accuracy, Matthews correlation coefficients, sensitivity, and specificity. Additionally, the feature selection was investigated to identify correlating factors for risk status. The results demonstrated that there were significant differences in the coagulation, liver, and kidney indices between deceased and surviving subjects (p<0.05). Aspartate aminotransferase, prothrombin time, prothrombin activity, total bilirubin, direct bilirubin, indirect bilirubin, alanine aminotransferase, urea nitrogen, and creatinine were the most highly correlated indices in PQ poisoning and showed statistical significance (p<0.05) in predicting PQ-poisoning prognoses. According to the feature selection, the most important correlated indices were found to be associated with aspartate aminotransferase, the aspartate aminotransferase to alanine ratio, creatinine, prothrombin time, and prothrombin activity. The method proposed here showed excellent results that were better than

  2. 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.

  3. A new machine-learning method to prognosticate paraquat poisoned patients by combining coagulation, liver, and kidney indices

    Science.gov (United States)

    Hu, Lufeng; Li, Huaizhong; Cai, Zhennao; Lin, Feiyan; Hong, Guangliang; Chen, Huiling; Lu, Zhongqiu

    2017-01-01

    The prognosis of paraquat (PQ) poisoning is highly correlated to plasma PQ concentration, which has been identified as the most important index in PQ poisoning. This study investigated the predictive value of coagulation, liver, and kidney indices in prognosticating PQ-poisoning patients, when aligned with plasma PQ concentrations. Coagulation, liver, and kidney indices were first analyzed by variance analysis, receiver operating characteristic curves, and Fisher discriminant analysis. Then, a new, intelligent, machine learning-based system was established to effectively provide prognostic analysis of PQ-poisoning patients based on a combination of the aforementioned indices. In the proposed system, an enhanced extreme learning machine wrapped with a grey wolf-optimization strategy was developed to predict the risk status from a pool of 103 patients (56 males and 47 females); of these, 52 subjects were deceased and 51 alive. The proposed method was rigorously evaluated against this real-life dataset, in terms of accuracy, Matthews correlation coefficients, sensitivity, and specificity. Additionally, the feature selection was investigated to identify correlating factors for risk status. The results demonstrated that there were significant differences in the coagulation, liver, and kidney indices between deceased and surviving subjects (p<0.05). Aspartate aminotransferase, prothrombin time, prothrombin activity, total bilirubin, direct bilirubin, indirect bilirubin, alanine aminotransferase, urea nitrogen, and creatinine were the most highly correlated indices in PQ poisoning and showed statistical significance (p<0.05) in predicting PQ-poisoning prognoses. According to the feature selection, the most important correlated indices were found to be associated with aspartate aminotransferase, the aspartate aminotransferase to alanine ratio, creatinine, prothrombin time, and prothrombin activity. The method proposed here showed excellent results that were better than

  4. Protein profiling of paraquat-exposed rat lungs following treatment with Acai (Euterpe oleracea Mart.) berry extract.

    Science.gov (United States)

    Kim, Yong-Sik; Jung, Hana; Zerin, Tamanna; Song, Ho-Yeon

    2013-03-01

    Paraquat (1,1'-dimethyl-4,4'-bipyridinium chloride, PQ) is a non-selective herbicide, and PQ poisoning by accidental or intentional ingestion is a cause of numerous fatalities around the world every year. Although a great deal of research has been conducted into the development of an acceptable treatment for PQ poisoning, no effective guidelines for patients have been developed thus far. Acai berry extract and juice have been highlighted in this regard, due to their observed antioxidant effects in various diseases. Furthermore, the acai berry has been used in dietary supplements, as it contains a variety of nutrients, including proteins, lipids, vitamins A, C and E and polyphenols. In this study, we conducted proteomic analysis of PQ-poisoned rat lungs to evaluate the changes in protein expression induced by PQ and to identify any protective effects of acai berry on the PQ poisoning. Our data revealed that the expression of the calcium signaling-related proteins calcium binding protein 1 (CaBP1), FK506 binding protein 4 (FKBP4), S100A6 and secreted protein acidic and rich in cysteine (Sparc, also known as osteonectin) were induced by PQ treatment and downregulated by acai berry treatment. However, the levels of protein kinase C substrate 80K-H were shown to be downregulated as the result of PQ treatment. Our results indicated that these proteins may function as biomarkers for acute poisoning by PQ exposure. Further studies may be necessary to understand their clinical relevance with regard to PQ poisoning.

  5. 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

    Directory of Open Access Journals (Sweden)

    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

  6. Quantification of Paraquat, MPTP, and MPP+ in brain tissue using microwave-assisted solvent extraction (MASE) and high-performance liquid chromatography-mass spectrometry.

    Science.gov (United States)

    Winnik, Bozena; Barr, Dana B; Thiruchelvam, Mona; Montesano, M Angela; Richfield, Eric K; Buckley, Brian

    2009-09-01

    Animal models, consistent with the hypothesis of direct interaction of paraquat (PQ) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) with specific areas of the central nervous system have been developed to study Parkinson's disease (PD) in mice. These models have necessitated the creation of an analytical method for unambiguous identification and quantitation of PQ and structurally similar MPTP and 1-methyl-4-phenylpyridinium ion (MPP+) in brain tissue. A method for determination of these compounds was developed using microwave-assisted solvent extraction (MASE) and liquid chromatography-mass spectrometry. Extraction solvent and microwave conditions such as power and time were optimized to produce recoveries of 90% for PQ 78% for MPTP and 97% for its metabolite MPP+. The chromatographic separation was performed on a C8, column and detection was carried out using an ion trap as an analyzer with electrospray ionization. Mass spectrometer parameters such as heated capillary temperature, spray voltage, capillary voltage and others were also optimized for each analyte. Analysis was done in selective ion-monitoring (SIM) mode using m/z 186 for PQ, m/z 174 for MPTP, and m/z 170 for MPP+. The method detection limit for paraquat in matrix was 100 pg, 40 pg for MPTP, and 20 pg MPP+.

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

    Directory of Open Access Journals (Sweden)

    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. Quantification of Paraquat, MPTP, and MPP+ in brain tissue using microwave-assisted solvent extraction (MASE) and high performance liquid chromatography-mass spectrometry

    Science.gov (United States)

    Winnik, Bozena; Barr, Dana B.; Thiruchelvam, Mona; Montesano, M. Angela; Richfield, Eric K.; Buckley, Brian

    2014-01-01

    Animal models, consistent with the hypothesis of direct interaction of paraquat (PQ) and 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) with specific areas of the central nervous system have been developed to study Parkinson’s disease (PD) in mice. These models have necessitated the creation of an analytical method for unambiguous identification and quantitation of PQ and structurally similar MPTP and 1-Methyl-4-phenylpyridinium ion (MPP+) in brain tissue. A method for determination of these compounds was developed using microwave-assisted solvent extraction (MASE) and liquid chromatography-mass spectrometry. Extraction solvent and microwave conditions such as power and time were optimized to produce recoveries of 90% for PQ 78% for MPTP and 97% for its metabolite MPP+. The chromatographic separation was performed on a C8, column and detection was carried out using an ion trap as an analyzer with electrospray ionization. Mass spectrometer parameters such as heated capillary temperature, spray voltage, capillary voltage and others were also optimized for each analyte. Analysis was done in Selective Ion Monitoring (SIM) mode using 186 m/z for PQ, m/z 174 for MPTP, and m/z 170 for MPP+. The method detection limit for paraquat in matrix was 100 pg and 40 pg for MPTP and 20 pg MPP+. PMID:19618168

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

    Science.gov (United States)

    Luo, Chao; Cai, Xiao-Teng; Du, Jin; Zhao, Tao-Lan; Wang, Peng-Fei; Zhao, Ping-Xia; Liu, Rui; Xie, Qi; Cao, Xiao-Feng; Xiang, Cheng-Bin

    2016-09-01

    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.

  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. [The role of transforming growth factor-β1/connective tissue growth factor signaling pathway in paraquat-induced pulmonary fibrosis].

    Science.gov (United States)

    Li, H H; Cai, Q; Wang, Y P; Liu, H R; Huang, M

    2016-07-20

    Objective: To investigate the effects of Paraquat on human embryonic lung fibroblasts (MRC5) and explore the role of transforming growth factor-β1/connective tissue growth factor signaling pathway in paraquat-induced pulmonary fibrosis. Methods: MRC5 cells were cultured with different concentration of PQ (0, 12.5, 25, 50, 100, 200, 400 μmol/L) for 24 h. The viability of cells was measured by MTT. The protein level of TGF-β1 were analyzed by ELISA after PQ treatment (0, 25, 50, 100 μmol/L) . To examine whether TGF-β1/CTGF signaling pathway was involved in paraquat-induced cytotoxicity, cells was divided into 6 groups: (1) control; (2) 25 μmol/L PQ group; (3) 50 μmol/L PQ group; (4) 100 μmol/L PQ group; (5) TGF-β1 positive control group (50 μmol/L rhTGF-β1) ; (6) stimulate group (100 μmol/L PQ+50 μmol/L TGF-β1) . The protein levels of p-Smad2, p-Smad3 and CTGF were assayed by western blot. The mRNA level of CTGF was assayed by real time RT-PCR. Results: MTT showed that cell viability decreased with increasing PQ concentration (P<0.05) . The protein expression of TGF-β1 treated with PQ (25, 50, 100 μmol/L) significantly increased compared with control in a dose-independent manner (P<0.05) . Exposure to PQ (25, 50, 100 μmol/L) induced increase of protein levels of p-Smad2 and p-Smad3. Noteworthy, the expression of p-Smad2 and p-Smad3 were dramatically increased following PQ plus TGF-β1 stimulation (P<0.05) . Exposure to PQ (50, 100μmol/L) induced increase of CTGF protein expression and similar greatly increase following PQ plus TGF-β1 stimulation (P<0.05) . Real time RT-PCR showed CTGF mRNA in all groups also significantly up-regulated compared with control (P<0.05) . Conclusion: TGF-β1 regulates the expression of target gene CTGF to exhibit its pro-fibrogenic effects by activating TGF-β1/Smad signaling pathway in PQ-induced pulmonary fibrosis.

  12. Germinación y residuos de plaguicida en semillas de coriandro (Coriandrum sativum L.) cultivadas con aplicación de glifosato y paraquat en precosecha

    OpenAIRE

    Aquilano, Claudio; Ricca, Alejandra; Fonti, Ana; Bazzigalupi, Omar

    2017-01-01

    Es conocida la aplicación de desecantes, para acelerar y uniformizar el secado del cultivo de coriandro y de las malezas, que facilitan la cosecha de semillas. Para conocer sus efectos sobre el poder germinativo y determinar el contenido de residuos de plaguicidas en semillas, se evaluaron glifosato y paraquat, aplicados en semillas con 62 y 47% de humedad (H), cosechadas con H

  13. Orally delivered water soluble Coenzyme Q10 (Ubisol-Q10) blocks on-going neurodegeneration in rats exposed to paraquat: potential for therapeutic application in Parkinson’s disease

    Science.gov (United States)

    2014-01-01

    Background Paraquat, still used as an herbicide in some parts of the world, is now regarded as a dangerous environmental neurotoxin and is linked to the development Parkinson’s disease (PD). Paraquat interacts with cellular redox systems and causes mitochondrial dysfunction and the formation of reactive oxygen species, which in turn, plays a crucial role in the pathophysiology of PD. Various antioxidant therapies have been explored with the expectations that they deliver health benefits to the PD patients, however, no such therapies were effective. Here we have tested the neuroprotective efficacy of a novel water-soluble CoQ10 (Ubisol-Q10), in a rat model of paraquat-induced neurodegeneration in order to evaluate its potential application in the management of PD. Results We have developed a rat model of progressive nigrostriatal degeneration by giving rats five intraperitoneal injections of paraquat (10 mg/kg/injection), once every five days. Neuronal death occurred over a period of 8 weeks with close to 50% reduction in the number of tyrosine hydroxylase-positive cells. Ubisol-Q10, at 6 mg CoQ10/kg body weight/day, was delivered as a supplement in drinking water. The intervention begun after the completion of paraquat injections when the neurodegenerative process had already began and about 20% of TH-positive neurons were lost. Ubisol-Q10 treatment halted the progression of neurodegeneration and remaining neurons were protected. The outcomes were evaluated based on the number of surviving tyrosine hydroxylase-positive neurons in the substantia nigra region and improved motor skills in response to the Ubisol-Q10 intervention. To maintain this neuroprotection, however, continuous Ubisol- Q10 supplementation was required, if withdrawn, the neuronal death pathway resumed, suggesting that the presence of CoQ10 was essential for blocking the pathway. Conclusion The CoQ10, given orally as Ubisol-Q10 in drinking solution, was effective in blocking the progression of

  14. The cannabinoid CP55,940 prolongs survival and improves locomotor activity in Drosophila melanogaster against paraquat: implications in Parkinson's disease.

    Science.gov (United States)

    Jimenez-Del-Rio, M; Daza-Restrepo, A; Velez-Pardo, C

    2008-08-01

    Cannabinoids have been shown to function as protective agents via receptor-independent and/or receptor-dependent mechanisms against stressful conditions. However, the neuroprotective mechanism of cannabinoids is far from conclusive. Therefore, the genuine antioxidant impact of cannabinoids in vivo is still uncertain. In this study, we demonstrate for the first time that CP55,940, a nonselective CB(1)/CB(2) cannabinoid receptor agonist, significantly protects and rescues Drosophila melanogaster against paraquat (PQ) toxicity via a receptor-independent mechanism. Interestingly, CP55,940 restores the negative geotaxis activity (i.e., climbing capability) of the fly exposed to PQ. Moreover, Drosophila fed with (1-200 microM) SP600125, a specific inhibitor of the stress responsive Jun-N-terminal kinase (JNK) signaling, and 20 mM PQ increased survival percentage and movement function (i.e., climbing capability) when compared to flies only treated with PQ. Taken together our results suggest that exogenous antioxidant cannabinoids can protect against and rescue from locomotor dysfunction in wild type (Canton-S) Drosophila exposed to stress stimuli. Therefore, cannabinoids may offer promising avenues for the design of molecules to prevent, delay, or ameliorate the treatment of population at high risk of suffering Parkinson disease.

  15. Paraquat exposure-induced Parkinson's disease-like symptoms and oxidative stress in Drosophila melanogaster: Neuroprotective effect of Bougainvillea glabra Choisy.

    Science.gov (United States)

    Soares, Jefferson J; Rodrigues, Daniela T; Gonçalves, Mayara B; Lemos, Maurício C; Gallarreta, Mariana S; Bianchini, Matheus C; Gayer, Mateus C; Puntel, Robson L; Roehrs, Rafael; Denardin, Elton L G

    2017-11-01

    Extracts from the leaves of Bougainvillea glabra Choisy are used in traditional medicines, but their actions on the central nervous system have not been studied. In the present study, we investigated the potential neuroprotective effects of Bougainvillea glabra Choisy leaf extract (BG extract) against paraquat (PQ)-induced neurotoxicity. Male adult wild-type flies (1- 4days old) were exposed to PQ (3.5mM) and/or BG extract (120μg/mL) through food for 4days. PQ-fed flies had decreased locomotor capacity in negative geotaxis and crossing number assays and had a higher incidence of mortality than the control group. PQ neurotoxicity was also associated with a marked decrease in dopamine levels and increase in acetylcholinesterase (AChE) activity, reactive oxygen species (ROS) production and lipid peroxidation. Co-exposure to BG extract prevented mortality, and dopamine depletion, improved locomotor performance and decreased AChE activity, ROS production and lipid peroxidation. GC-MS and HPLC analyses of BG extract revealed the presence of many antioxidant compounds such as phytol, α,γ-tocopherol, squalene, stigmasterol, geranylgeraniol, quercetin, and caffeic, vanillic, coumaric, ferulic acids. Our results showed neuroprotective effects of BG extract, reflecting the presence of antioxidant compounds. Thus, we suggested that B. glabra leaves could be considered an effective agent in the prevention of neurological disorders, where dopamine depletion and/or oxidative stress are involved, as in Parkinson's disease (PD). Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  16. Supplementation of Spirulina (Arthrospira platensis) Improves Lifespan and Locomotor Activity in Paraquat-Sensitive DJ-1βΔ93 Flies, a Parkinson's Disease Model in Drosophila melanogaster.

    Science.gov (United States)

    Kumar, Ajay; Christian, Pearl K; Panchal, Komal; Guruprasad, B R; Tiwari, Anand K

    2017-09-03

    Spirulina (Arthrospira platensis) is a cyanobacterium (blue-green alga) consumed by humans and other animals because of its nutritional values and pharmacological properties. Apart from high protein contents, it also contains high levels of antioxidant and anti-inflammatory compounds, such as carotenoids, β-carotene, phycocyanin, and phycocyanobilin, indicating its possible pharmaco-therapeutic utility. In the present study using DJ-1βΔ93 flies, a Parkinson's disease model in Drosophila, we have demonstrated the therapeutic effect of spirulina and its active component C-phycocyanin (C-PC) in the improvement of lifespan and locomotor behavior. Our findings indicate that dietary supplementation of spirulina significantly improves the lifespan and locomotor activity of paraquat-fed DJ-1βΔ93 flies. Furthermore, supplementation of spirulina and C-PC individually and independently reduced the cellular stress marked by deregulating the expression of heat shock protein 70 and Jun-N-terminal kinase signaling in DJ-1βΔ93 flies. A significant decrease in superoxide dismutase and catalase activities in spirulina-fed DJ-1βΔ93 flies tends to indicate the involvement of antioxidant properties associated with spirulina in the modulation of stress-induced signaling and improvement in lifespan and locomotor activity in Drosophila DJ-1βΔ93 flies. Our results suggest that antioxidant boosting properties of spirulina can be used as a nutritional supplement for improving the lifespan and locomotor behavior in Parkinson's disease.

  17. 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.

  18. Determination of nitrate by the IE-HPLC-UV method in the brain tissues ofWistar rats poisoned with paraquat

    Directory of Open Access Journals (Sweden)

    MARIJANA CURCIC JOVANOVIC

    2007-04-01

    Full Text Available This work was a part of an initial study regarding the involvement of reactive nitrogen species (RNS in paraquat (PQ neurotoxicity. The nitrate concentration in the vulnerable regions of the brain (cortex, striatum and hippocampus of Wistar rats was used as a measure of nitric oxide (NO production or catabolism of the formed RNS. The tissue homogenates were deproteinized with acetonitrile and then centrifuged. Nitrate was measured in filtrated supernatants by simple and rapid isocratic ion-exchange high performance liquid chromatography with UV detection (IE-HPLC-UV at 214 nm. The mobile phase (pH 8.5 consisted of borate buffer/gluconate concentrate, methanol, acetonitrile and deionized water (2:12:12:74, v/v/v/v, and the flow rate was 1.3 mL/min. Physiological nitrate levels (18.8 ± 6.1 nmol/mg of proteins, as well as a diverse range of nitrate concentrations could be determined with good precision (CV = 2.2 % and accuracy (recovery of spiked samples was 99 ± 4% in the brain tissue homogenates. Linearity was achieved in the range of nitrate from 0‑80 mM. The retention time of nitrate anion was 5.3 ± 0.3 min.

  19. The potential of synthetic thiourea compound to reduce the cytotoxic and genotoxic effects of paraquat in Hordeum vulgare and cultured human lymphocytes.

    Science.gov (United States)

    Gateva, Svetla; Jovtchev, Gabriele; Stergios, Mila; Yonova, Petranka

    2012-03-01

    This work evaluated the ability of one synthetic compound 1-(4-fluorophenylthiocarbamoyl)-4-methyl-piperazine (FTMP), thiourea derivative to reduce cytotoxic and genotoxic effects of free radical inducer paraquat (PQ) in two different test systems Hordeum vulgare and human lymphocytes in vitro. The mitotic index was used as a marker for cytotoxicity. To indicate genotoxicity, chromosome aberrations test and micronucleus induction test were used. FTMP manifested a weak genotoxic effect in both test systems. Clear evidence was obtained that conditioning treatment with FTMP (10(-6) , 5 × 10(-6) , and 10(-5) mol/l) could decrease chromosome aberrations and micronuclei induced by PQ in both test systems. "Aberration hot spots" in heterochromatin containing segments were reduced. The present data show that the thiourea synthetic compound FTMP provides genome protection against the harmful action of oxidative stress inductor PQ. Human lymphocytes were found to be more sensitive to the cytotoxic and clastogenic effects of FTMP conditioning treatment than Hordeum vulgare. Revealing the protective action of newly synthesized compounds could contribute to the improvement of our present knowledge of the mechanisms of mutagenesis and antimutagenesis. Copyright © 2010 Wiley Periodicals, Inc.

  20. The laws governing ionic liquid extraction of cations: partition of 1-ethylpyridinium monocation and paraquat dication in ionic liquid/water biphasic systems.

    Science.gov (United States)

    Hamamoto, Takuya; Okai, Miho; Katsuta, Shoichi

    2015-05-21

    To find the laws governing the extraction of cations from aqueous solutions into hydrophobic ionic liquids (ILs), we investigated the partition of 1-ethylpyridinium monocation and paraquat (1,1'-dimethyl-4,4'-bipyridinium) dication in various IL/water biphasic systems. Ten different ILs of 1-butyl-3-methylimidazolium-based or bis(trifluoromethanesulfonyl)amide-based salts were used. The distribution ratio of the target cations (T(n+)) was dependent on the initial concentration in the aqueous phase and also very sensitive to the kind of IL. The behavior was quantitatively explained on the basis of a model in which the extraction goes through both the ion exchange and ion pair transfer processes, while keeping the product of the aqueous concentrations of the IL constituent ions a constant value (solubility product, Ksp). The distribution ratio of T(n+) is expressed as a function of the difference between the initial and equilibrium concentrations of T(n+) in the aqueous phase (Δ[T(n+)]W), the aqueous solubility of IL (Ksp(1/2)), and the cation valence n. The distribution ratio is a nearly constant value (D0) when Δ[T(n+)]W ≪ Ksp(1/2)/n and decreases inversely proportional to the nth power of Δ[T(n+)]W when Δ[T(n+)]W ≫ Ksp(1/2)/n. The log D0 versus log Ksp(1/2) plot gives a linear relationship with a slope of +n for the ILs with the same anion but different cations and that with a slope of nearly -n for the ILs with the same cation but different anions. This means that the extractability dependence on the kinds of IL constituent ions is greater for the divalent cation than for the monovalent one.

  1. Induction and activation of P-glycoprotein by dihydroxylated xanthones protect against the cytotoxicity of the P-glycoprotein substrate paraquat.

    Science.gov (United States)

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

    2014-04-01

    Xanthones are a family of compounds with several known biological activities and therapeutic potential for which information on their interaction with membrane transporters is lacking. Knowing that P-glycoprotein (P-gp) acts as a cellular defense mechanism by effluxing its toxic substrates, the aim of this study was to investigate the potential of five dihydroxylated xanthones as inducers of P-gp expression and/or activity and to evaluate whether they could protect Caco-2 cells against the cytotoxicity induced by the toxic P-gp substrate paraquat (PQ). After 24 h of incubation, all tested xanthones 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, after a short 45-min incubation, all the tested xanthones induced a rapid increase in P-gp activity, indicating direct pump activation without increased P-gp protein expression. The tested compounds also increased P-gp ATPase activity in MDR1-Sf9 membrane vesicles, demonstrating to be P-gp substrates. Moreover, when simultaneously incubated with PQ, all xanthones significantly reduced the cytotoxicity of the herbicide, and these protective effects were completely reversed upon incubation with a specific P-gp inhibitor. In silico studies evaluating the interactions between xanthones and P-gp in the presence of PQ suggested that a co-transport mechanism may be operating. A quantitative structure-activity relationship model was developed and validated, and the maximal partial charge for an oxygen atom was the descriptor predicted as being implicated in P-gp activation by the dihydroxylated xanthones. These results disclose new perspectives in preventing PQ- and other P-gp substrates-induced poisonings.

  2. The value of APACHE II in predicting mortality after paraquat poisoning in Chinese and Korean population: A systematic review and meta-analysis.

    Science.gov (United States)

    Huang, Jianshu; Xuan, Dandan; Li, Xiuju; Ma, Li; Zhou, Yuanling; Zou, Hejian

    2017-07-01

    The Acute Physiology and Chronic Health Evaluation II (APACHE II) score is used to determine disease severity and predict outcomes in critically ill patients. However, the prognostic significance of APACHE after acute paraquat (PQ) poisoning remains unclear. The meta-analysis was aimed to study the value of APACHE II in predicting mortality in PQ-exposed Chinese and Korean patients. Databases that included PubMed, Embase, Cochrane Library, and the Chinese National Knowledge Infrastructure were searched through August 2016. Studies using APACHE II to predict mortality in PQ-poisoned patients were selected. The odds ratio and weighted mean difference (WMD) were used to pool binary and continuous data. Additionally, we aggregated sensitivity, specificity, and other measures of accuracy. Statistical analyses were made using the Stata V.13.0 software. This study included 29 studies, and 25 studies evaluated APACHE II scores on admission. Pooled data showed that survivors had significantly lower total scores than nonsurvivors (WMD = -7.29, and I = 98.2%, both P APACHE II score ≥5 for predicting mortality was 75% and the pooled specificity was 86%. The positive likelihood ratio (PLR) was 5.3 and the negative likelihood ratio (NLR) was 0.29. The pooled sensitivity of an APACHE II score ≥10 for predicting mortality was 88% and the pooled specificity was 84%. The pooled PLR and NLR was 5.5 and 0.15, respectively. This study showed PQ-poisoned nonsurvivors had significantly higher APACHE II score than did survivors. APACHE II scores satisfactorily predicted mortality.

  3. Cytoprotective effect of bioactive sea buckthorn extract on paraquat-exposed A549 cells via induction of Nrf2 and its downstream genes.

    Science.gov (United States)

    Podder, Biswajit; Kim, Yong-Sik; Song, Ho-Yeon

    2013-12-01

    The extract of sea buckthorn (SBT) [Hippophae rhamnoides L. (Elaeagnaceae)], is used as a food supplement and traditional medicine in numerous countries. This study investigated the protective effects of the functional extract of SBT against paraquat (PQ)-induced toxicity via antioxidant mechanisms in A549 cells. The methanol extract of SBT (25-200 µg/ml) was used to protect cells against PQ (200 µM)-induced cell death. A viability assay was conducted using 3-(4,5-dimethylthioazol-2-ly)-2,5-diphenyltetrazolium bromide and lactate dehydrogenase (LDH). Total intracellular reactive oxygen species (ROS) were measured and plotted. For validation of the SBT-induced expression of nuclear factor-E2-related factor 2 (Nrf2) and its target genes, western blot analysis and qPCR were performed. The present study showed that pretreatment of A549 cells with SBT extract significantly attenuated PQ (200 µM)-induced cellular toxicity. The maximum cytoprotective effect was identified using 200 µg/ml SBT extract; it began 24 h following exposure and was sustained up to 120 h (P<0.05). SBT extract significantly reduced LDH activity by 35.63% and ROS levels by 30.90% (P<0.05). Pretreatment with SBT extract activated Nrf2 mRNA and protein expression and its nuclear translocation. The SBT extract effectively induced Nrf2 target genes, such as NAD(P)H dehydrogenase quinone 1, glutathione peroxidase 1, glutathione reductase and catalase following treatment with PQ. Based on these results, it was hypothesized that SBT extract may be used as a potential therapeutic agent for the treatment of various oxidative stress-related diseases.

  4. Melatonin application to Pisum sativum L. seeds positively influences the function of the photosynthetic apparatus in growing seedlings during paraquat-induced oxidative stress

    Directory of Open Access Journals (Sweden)

    Katarzyna Szafranska

    2016-11-01

    Full Text Available Melatonin, due to its pleiotropic effects plays an important role improving tolerance to stresses. Plants increase endogenous melatonin synthesis when faced with harsh environments as well as exogenously-applied melatonin limits stress injuries. Presented work demonstrated that single melatonin application into the seeds during pre-sowing priming improved oxidative stress tolerance of growing seedlings exposed to paraquat (PQ. PQ is a powerful herbicide which blocks the process of photosynthesis under light conditions due to free radicals excess production, when O2 is rapidly converted to O2•- and subsequently to other ROS. The parameters of chlorophyll fluorescence (Fv/Fm, Fv/Fo, Rfd, ΦPSII, qP and NPQ in all variants of pea leaves (derived from control non treated seeds – C, and those hydroprimed with water – H, and hydroprimed with melatonin water solution 50 or 200 μM – H-MEL50 and H-MEL200, respectively were analysed as a tool for photosynthetic efficacy testing. Moreover stability of the photosynthetic pigments (chlorophylls a, b, and carotenoids was also monitored under oxidative stress conditions. The results suggest that melatonin applied into the seed significantly enhances oxidative stress tolerance in growing seedlings. This beneficial effect was reflected in reduced accumulation of O2•- in leaf tissues, preservation of photosynthetic pigments, improved functioning of the photosynthetic apparatus and higher water content in the tissues during PQ-mediated stress. Our findings provide evidence for the physiological role of this molecule and serve as a platform for its possible applications in agricultural or related areas of research.

  5. 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. PMID:26300641

  6. Heat shock protein-70 (Hsp-70 suppresses paraquat-induced neurodegeneration by inhibiting JNK and caspase-3 activation in Drosophila model of Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Arvind Kumar Shukla

    Full Text Available Parkinson's disease (PD is one of the most common neurodegenerative disorders with limited clinical interventions. A number of epidemiological as well as case-control studies have revealed an association between pesticide exposure, especially of paraquat (PQ and occurrence of PD. Hsp70, a molecular chaperone by function, has been shown as one of the modulators of neurological disorders. However, paucity of information regarding the protective role of Hsp70 on PQ-induced PD like symptoms led us to hypothesize that modulation of hsp70 expression in the dopaminergic neurons would improve the health of these cells. We took advantage of Drosophila, which is a well-established model for neurological research and also possesses genetic tools for easy manipulation of gene expression with limited ethical concern. Over-expression of hsp70 was found to reduce PQ-induced oxidative stress along with JNK and caspase-3 mediated dopaminergic neuronal cell death in exposed organism. Further, anti-apoptotic effect of hsp70 was shown to confer better homeostasis in the dopaminergic neurons of PQ-exposed organism as evidenced by their improved locomotor performance and survival. The study has merit in the context of human concern since we observed protection of dopaminergic neurons in PQ-exposed organism by over-expressing a human homologue of hsp70, HSPA1L, in these cells. The effect was parallel to that observed with Drosophila hsp70. These findings reflect the potential therapeutic applicability of hsp70 against PQ-induced PD like symptoms in an organism.

  7. 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 diet with cooked 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.

  8. Combined exposure to Maneb and Paraquat alters transcriptional regulation of neurogenesis-related genes in mice models of Parkinson’s disease

    Directory of Open Access Journals (Sweden)

    Desplats Paula

    2012-09-01

    Full Text Available Abstract Background Parkinson's disease (PD is a multifactorial disease where environmental factors act on genetically predisposed individuals. Although only 5% of PD manifestations are associated with specific mutations, majority of PD cases are of idiopathic origin, where environment plays a prominent role. Concurrent exposure to Paraquat (PQ and Maneb (MB in rural workers increases the risk for PD and exposure of adult mice to MB/PQ results in dopamine fiber loss and decreased locomotor activity. While PD is characterized by neuronal loss in the substantia nigra, we previously showed that accumulation of α-synuclein in the limbic system contributes to neurodegeneration by interfering with adult neurogenesis. Results We investigated the effect of pesticides on adult hippocampal neurogenesis in two transgenic models: Line 61, expressing the human wild type SNCA gene and Line LRRK2(G2019S, expressing the human LRRK2 gene with the mutation G2019S. Combined exposure to MB/PQ resulted in significant reduction of neuronal precursors and proliferating cells in non-transgenic animals, and this effect was increased in transgenic mice, in particular for Line 61, suggesting that α-synuclein accumulation and environmental toxins have a synergistic effect. We further investigated the transcription of 84 genes with direct function on neurogenesis. Overexpresion of α-synuclein resulted in the downregulation of 12% of target genes, most of which were functionally related to cell differentiation, while LRRK2 mutation had a minor impact on gene expression. MB/PQ also affected transcription in non-transgenic backgrounds, but when transgenic mice were exposed to the pesticides, profound alterations in gene expression affecting 27% of the studied targets were observed in both transgenic lines. Gene enrichment analysis showed that 1:3 of those genes were under the regulation of FoxF2 and FoxO3A, suggesting a primary role of these proteins in the response to

  9. 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

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

    African Journals Online (AJOL)

    E. HJ. Meaker and T.P.N. Coetsee. Agricultural Research Station, P.O. Box 626, Dundee,3000. (IGy words:. Foggoge, Herbicide, steerc). (Sleutelwoorde : lUin t erwe idin g, Onkruidd oder, b ee ste ). Erogrostis ... public. The use of E. currula for winter forage is, how- ... ference in l-ick intake, the average CP equivalent intake.

  11. 1,1′-[(1,3-Dihydroxypropane-2,2-diyldimethylene]dipyridinium bis(hexafluorophosphate

    Directory of Open Access Journals (Sweden)

    Ai-lin Yuan

    2011-05-01

    Full Text Available The title compound, C15H20N2O22+·2PF6−, was prepared by anion exchange of two bromide ions in the ionic liquid 2,2′-bis-(pyridinium-1-ylmethyl-propane-1,3-diol dibromide with potassium hexafluorophosphate. The two pyridine rings are planar (r.m.s. deviations = 0.008 and 0.00440 Å and make a dihedral angle of 44.0 (2°. Intermolecular O—H...F and C—H...F interactions occur. The four F atoms in each anion were refined as disordered over two sets of sites with an occupancy ration of 0.700 (19:0.300 (19.

  12. 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

    by OH is k=(2.5±0.2)× 108 dm3 mol–1 s–1. The resulting transient absorbs at λ max= 470 nm (ε 470= 1600±70 m2 mol–1) and decays with 2k=(1.3±0.2)× 108 dm3 mol–1 s–1. In strongly alkaline solutions (pH ⩾ 13.8) the O– radical anion reacts preferentially by hydrogen abstraction from the methyl group, k=(1...

  13. 40 CFR 180.205 - Paraquat; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ..., green 0.05 Papaya 0.05 Passionfruit 0.2 Pea and bean, dried shelled, except soybean, subgroup 6C, except guar bean 0.3 Pea and bean, succulent shelled, subgroup 6B 0.05 Pea, field, hay 0.8 Pea, field, vines 0..., legume, edible podded, subgroup 6A 0.05 Wheat, forage 0.5 Wheat, grain 1.1 Wheat, hay 3.5 Wheat, straw 50...

  14. 3,3′-Dimethyl-1,1′-[(1,3-dihydroxypropane-2,2-diyldimethylidene]diimidazolium bis(hexafluorophosphate

    Directory of Open Access Journals (Sweden)

    Guo-Wei Wang

    2010-12-01

    Full Text Available The title compound, C13H22N4O22+·2PF6−, was prepared by the anion exchange of the dibromide ionic liquid with potassium hexafluorophosphate. The two imidazole rings are each planar (r.m.s. deviations = 0.0016 and 0.0060 Å and make a dihedral angle of 45.3 (18°. Intramolecular O—H...F hydrogen bonds occur. Intermolecular C—H...F, O—H...O and C—H...O hydrogen bonds stabilize the crystal structure.

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

    KAUST Repository

    Rieb, Julia

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

    OpenAIRE

    Xi Ning; Yao Sun; Changchun Wang; Weilin Zhang; Meihao Sun; Haitao Hu; Jianzhong Liu; Ling Yang

    2018-01-01

    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...

  17. Atrazine and Methyl Viologen Effects on Chlorophyll-a Fluorescence Revisited-Implications in Photosystems Emission and Ecotoxicity Assessment.

    Science.gov (United States)

    Iriel, Analia; Novo, Johanna M; Cordon, Gabriela B; Lagorio, María G

    2014-01-01

    In this work, we use the effect of herbicides that affect the photosynthetic chain at defined sites in the photosynthetic reaction steps to derive information about the fluorescence emission of photosystems. The interpretation of spectral data from treated and control plants, after correction for light reabsorption processes, allowed us to elucidate current controversies in the subject. Results were compatible with the fact that a nonnegligible Photosystem I contribution to chlorophyll fluorescence in plants at room temperature does exist. In another aspect, variable and nonvariable chlorophyll fluorescence were comparatively tested as bioindicators for detection of both herbicides in aquatic environment. Both methodologies were appropriate tools for this purpose. However, they showed better sensitivity for pollutants disconnecting Photosystem II-Photosystem I by blocking the electron transport between them as Atrazine. Specifically, changes in the (experimental and corrected by light reabsorption) red to far red fluorescence ratio, in the maximum photochemical quantum yield and in the quantum efficiency of Photosytem II for increasing concentrations of herbicides have been measured and compared. The most sensitive bioindicator for both herbicides was the quantum efficiency of Photosystem II. © 2013 The American Society of Photobiology.

  18. 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.

  19. 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.

  20. Posible contribución del paraquat al desarrollo de la enfermedad de Parkinson

    OpenAIRE

    C. A. Elena-Real; R. Pasión-Galván; M. R. Pérez-Artés; M Puerto

    2012-01-01

    La enfermedad de Parkinson (PD) es una de las enfermedades neurodegenerativas más comunes relacionadas con la edad que afecta a millones de personas en todo el mundo. Existen pruebas sólidas que apoyan el papel de los radicales libres, estrés oxidativo, disfunción mitocondrial y agregación de proteínas en el mecanismo de acción tóxica y muerte neuronal en la PD. Los factores ambientales, especialmente, los plaguicidas constituyen uno de los principales grupos de agentes neurotóxicos asociados...

  1. Structure-property relationships in redox-gated single molecule junctions - A comparison of pyrrolo-tetrathiafulvalene and viologen redox groups

    DEFF Research Database (Denmark)

    Leary, E.; Higgins, S.J.; van Zalinge, H.

    2008-01-01

    We demonstrate that the electrical 'switching" behavior of single molecules connected between two electrode contacts can be controlled by altering their structure and electrochemical characteristics. The electrical properties of gold vertical bar molecule vertical bar gold single molecule junctions...

  2. 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.

    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 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

    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.

  4. 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

    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.

  5. 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

    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.

  6. 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.

  7. 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

    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.

  8. 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

    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.

  9. 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.

    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.

  10. 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.

  11. 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.

  12. 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

    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 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

    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 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.

  15. 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.

  16. Difference in oxidative stress tolerance between rice cultivars estimated with chlorophyll fluorescence analysis.

    Science.gov (United States)

    Kasajima, Ichiro

    2017-04-26

    Oxidative stress is considered to be involved in growth retardation of plants when they are exposed to a variety of biotic and abiotic stresses. Despite its potential importance in improving crop production, comparative studies on oxidative stress tolerance between rice (Oryza sativa L.) cultivars are limited. This work describes the difference in term of oxidative stress tolerance between 72 rice cultivars. 72 rice cultivars grown under naturally lit greenhouse were used in this study. Excised leaf discs were subjected to a low concentration of methyl viologen (paraquat), a chemical reagent known to generate reactive oxygen species in chloroplast. Chlorophyll fluorescence analysis using a two-dimensional fluorescence meter, ion leakage analysis as well as the measurement of chlorophyll contents were used to evaluate the oxidative stress tolerance of leaf discs. Furthermore, fluorescence intensities were finely analyzed based on new fluorescence theories that we have optimized. Treatment of leaf discs with methyl viologen caused differential decrease of maximum quantum yield of photosystem II (Fv/Fm) between cultivars. Decrease of Fv/Fm was also closely correlated with increase of ion leakage and decrease of chlorophyll a/b ratio. Fv/Fm was factorized into photochemical and non-photochemical parameters to classify rice cultivars into sensitive and tolerant ones. Among the 72 compared rice cultivars, the traditional cultivar Co13 was identified as the most tolerant to oxidative stress. Koshihikari, a dominant modern Japonica cultivar in Japan as well as IR58, one of the modern Indica breeding lines exhibited a strong tolerance to oxidative stress. Close correlation between Fv/Fm and chlorophyll a/b ratio provides a simple method to estimate oxidative stress tolerance, without measurement of chlorophyll fluorescence with special equipment. The fact that modern cultivars, especially major cultivars possessed tolerance to oxidative stress suggests that oxidative stress

  17. Shewanella oneidensis Hfq promotes exponential phase growth, stationary phase culture density, and cell survival

    Directory of Open Access Journals (Sweden)

    Brennan Christopher M

    2013-02-01

    Full Text Available Abstract Background Hfq is an RNA chaperone protein that has been broadly implicated in sRNA function in bacteria. Here we describe the construction and characterization of a null allele of the gene that encodes the RNA chaperone Hfq in Shewanella oneidensis strain MR-1, a dissimilatory metal reducing bacterium. Results Loss of hfq in S. oneidensis results in a variety of mutant phenotypes, all of which are fully complemented by addition of a plasmid-borne copy of the wild type hfq gene. Aerobic cultures of the hfq∆ mutant grow more slowly through exponential phase than wild type cultures, and hfq∆ cultures reach a terminal cell density in stationary phase that is ~2/3 of that observed in wild type cultures. We have observed a similar growth phenotype when the hfq∆ mutant is cultured under anaerobic conditions with fumarate as the terminal electron acceptor, and we have found that the hfq∆ mutant is defective in Cr(VI reduction. Finally, the hfq∆ mutant exhibits a striking loss of colony forming units in extended stationary phase and is highly sensitive to oxidative stress induced by H2O2 or methyl viologen (paraquat. Conclusions The hfq mutant in S. oneidensis exhibits pleiotropic phenotypes, including a defect in metal reduction. Our results also suggest that hfq mutant phenotypes in S. oneidensis may be at least partially due to increased sensitivity to oxidative stress.

  18. 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

  19. 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.

  20. 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.

    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.

  1. 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.

    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 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.

  3. 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.

    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 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.

    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. 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

  6. 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...

  7. 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

  8. 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…

  9. UTILIZATION OF SWEETPOTATO BASED CONFECTION ...

    African Journals Online (AJOL)

    oma

    ABSTRACT. The study was conducted to examine the effect of paraquat herbicide on growth characteristics of cowpea. The paraquat herbicide was applied at two rates; 0.50 and 1.00kg ai/ha. Information was obtained on the vegetative growth parameters of cowpea which included plant height, number of leaves, leaf area, ...

  10. NCBI nr-aa BLAST: CBRC-CPOR-01-0486 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-CPOR-01-0486 ref|ZP_01162863.1| putative paraquat-inducible protein A [Photobacterium... sp. SKA34] gb|EAR53385.1| putative paraquat-inducible protein A [Photobacterium sp. SKA34] ZP_01162863.1 0.29 26% ...

  11. NCBI nr-aa BLAST: CBRC-ACAR-01-0319 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-ACAR-01-0319 ref|YP_309926.1| paraquat-inducible protein A [Shigella sonnei Ss...046] gb|AAZ87691.1| paraquat-inducible protein A [Shigella sonnei Ss046] YP_309926.1 2.6 35% ...

  12. Journal of Agriculture and Social Research (JASR) VOL. 10, No. 2 ...

    African Journals Online (AJOL)

    oma

    ABSTRACT. The experiment reported herein was undertaken to determine the toxicological effect of paraquat as post emergence herbicide on yield of cowpea. Two rates of paraquat 0.50 kg ai/ha and 1.00kg ai/ha were applied as post emergence herbicide in pot experiment with fallow weed population; which examined ...

  13. Evaluation of neuroprotective properties of two synthetic prenylated ...

    African Journals Online (AJOL)

    induced SH-SY5Y neurotoxicity. Further investigations to elucidate the detailed molecular mechanisms of neuroprotection by SX2 are warranted. Keywords: Prenylation, Xanthone derivatives, Neuroprotection, Paraquat, Dopamine, Neurotoxicity ...

  14. 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)....

  15. NCBI nr-aa BLAST: CBRC-ACAR-01-0319 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-ACAR-01-0319 ref|YP_540031.1| paraquat-inducible protein A [Escherichia coli U...TI89] ref|YP_852074.1| PqiA [Escherichia coli APEC O1] gb|ABE06500.1| paraquat-inducible protein A [Escheric...hia coli UTI89] gb|ABJ00360.1| PqiA [Escherichia coli APEC O1] YP_540031.1 4.5 35% ...

  16. Energetic dose: Beyond fire and flint?

    Science.gov (United States)

    Linder, G.; Rattner, B.; Cohen, J.

    2000-01-01

    Nutritional and bioenergetic interactions influence exposure to environmental chemicals and may affect the risk realized when wildlife are exposed in the field. Here, food-chain analysis focuses on prairie voles (Microtus ochrogaster) and the evaluation of chemical risks associated with paraquat following 10-d dietary exposures. Reproductive effects were measured in 60-d trials that followed exposures to paraquat-tainted feed: control (untainted feed); 21 mg paraquat/kg feed; 63 mg paraquat/kg feed; and feed-restricted control (untainted feed restricted to 60% baseline consumption). Reproductive success was evaluated in control and treated breeding pairs, and a preliminary bioenergetics analysis was completed in parallel to derive exposure dose. Although reproductive performance differed among groups, feed-restriction appeared to be the dominant treatment effect observed in these 10-d feeding exposure/limited reproductive trials. Exposure dose ranged from 3.70-3.76 to 9.41-11.51 mg parquat/kg BW/day at 21 and 63 mg paraquat/kg feed stock exposures, respectively. Energetic doses as ug paraquat/kcal yielded preliminary estimates of energetic costs associated with paraquat exposure, and were similar within treatments for both sexes, ranging from 4.2-5.5 and 13.1-15.0 ug paraquat/kcal for voles exposed to 21 mg/kg feed stock and 63 mg/kg feed stock, respectively. Given the increasing likelihood that environmental chemicals will be found in wildlife habitat at 'acceptable levels', the critical role that wildlife nutrition plays in evaluating ecological risks should be fully integrated into the assessment process. Tools applied to the analysis of risk must gain higher resolution than the relatively crude methods we currently bring to the process.

  17. 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)

  18. 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.

  19. Efeito dos herbicidas diuron, glifosato e paraquat e curvas de distribui??o de sensibilidade de esp?cies (CDSE) para a prote??o da diversidade de macr?fitas aqu?ticas da regi?o Amaz?nica.

    OpenAIRE

    Campos, Paola Souto

    2014-01-01

    O ecossistema aqu?tico da Amaz?nia vem sendo alvo de contamina??o ambiental pelo uso indiscriminado de herbicidas, colocando em risco a diversidade e abund?ncia das macr?fitas aqu?ticas da regi?o. Pouco se sabe a respeito dos efeitos dos herbicidas em esp?cies de macr?fitas aqu?ticas amaz?nicas, sendo a maioria dos estudos ecotoxicol?gicos desenvolvidos com a esp?cie Lemna sp., que ? utilizada como representativa dos efeitos dos agrot?xicos sobre a comunidade de macr?fitas. Al?m disso, os val...

  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....

  1. Thermo- and electro-dual responsive poly(ionic liquid) electrolyte based smart windows.

    Science.gov (United States)

    Chen, Fei; Ren, Yongyuan; Guo, Jiangna; Yan, Feng

    2017-01-31

    Thermo- and electro-dual responsive poly(ionic liquid) (PIL) based electrolytes were synthesized by co-polymerization of N-isopropylacrylamide (NIPAM) with (or without) 3-butyl-1-vinyl-imidazolium bromide ([BVIm][Br]) using diallyl-viologen (DAV) as both the cross-linking agent and electrochromic material.

  2. Reversible luminescence switch in a photochromic metal-organic framework.

    Science.gov (United States)

    Sun, Jian-Ke; Cai, Li-Xuan; Chen, Yong-Juan; Li, Zhao-Hui; Zhang, Jie

    2011-06-28

    Eu(III) ions have been introduced into a photoactive viologen system to yield a polyrotaxane-like metal-organic framework, which exhibits reversible photochromism and luminescence modulation with a non-destructive readout capability in the solid state. This journal is © The Royal Society of Chemistry 2011

  3. 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 .... Electrochemical studies of redox probes in self-organized lyotropic liquid crystalline systems. 631. Figure 2. ..... can occupy the inter-columnar space of the micelle. As a result, the ...

  4. 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

  5. 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)

  6. Efeito de desfolhantes na cultura algodoeira (Gossypium hirsutum L. no Triângulo Mineiro Effects of defoliants on cotton (Gossypium hirsutum L. at Triângulo Mineiro

    Directory of Open Access Journals (Sweden)

    J. P. Del C. Laca-Buendia

    1979-12-01

    Full Text Available Foram testados 4 desfolhantes com diferentes doses, e em misturas, sobre a cultivar IAC 13-1 em solo argiloso de Ipiaçú-MG. Os tratamentos constituiram de 0,71 e 1,42 kg i.a./ha de folex (71,2% de fosforotritoato de tributila, 1,06 e 1,41 kg i.a./ha de def (70,5% de s,s,s-tributiltritiofosfato, 0,36 e 0,54 kg i.a.fha de paraquat (36,2% de 1,1 dimetil-4,4' bipiridilio-dicloreto, 1,92 kg i.a./ha de etileno (48% de ácido cloroetilfosfórico, paraquat + def (0,36 + 0,70 kg i.a./ha, paraquat + def. (0,54 + 1,41 kg i.a./ha, paraquat + folex (0,36 + 0,70 kg i.a./ha, paraquat + folex (0,54 + 1,42 kg i.a./ha, paraquat (0,36 e 0,54 kg i.a./ha e urna testemunha isenta de desfolhantes. As aplicações foram feitas com 70% a 80% de capulhos abertos usando 800 1 de água/ha. A avaliação dos resultados consistiu na contagem de folhas secas + verdes e dos efeitos dos desfolhantes sobre plantas daninhas segundo a escala E.W.R.C. Def (1,41 kg i.a./ha, paraquat + folex (0,54 + 1,42 kg i.a./ha e paraquat + def (0,54 + 1,41 kg i.a./ha foram os melhores na avaliação feita 5 dias após a aplicação. O rebrotamento, causado pelas chuvas, igualou todos os tratamentos aos 10 dias, diferenciando-os apenas da testemunha e, aos 15 dias, igualando-os a ela. Todos os tratamentos com paraquat resultaram em melhor controle sobre plantas daninhas que os demais, contribuindo para facilitar a colheita mecânica e melhorar o tipo de algodão. Os tratamentos estudados não afetaram as características tecnológicas da fibra.Four defoliants were tested, alone and blended at different rates on cotton cv. IAC 13-1 on clay soil of Ipiaçu-MG. The treatments consisted of 0,71 and 1,42 kg i.a./ha of folex (71,2% of tributyl phosphorotrithioate, 1,06 and 1,41 kg i.a./ha of def (70,5% of s,s,s, - tributyl phosphorotrithioate, 0,36 and 0,54 kg i.a./ha of paraquat (36,2% of 1'1 dime thyl-4-4'- bipyridyldiylium ion, 1,92 kg i.a./ha of ethrel (48% of chlorethyphosphoric acid, paraquat

  7. Suicide prevention through means restriction

    DEFF Research Database (Denmark)

    Knipe, Duleeka W.; Chang, Shu-Sen; Dawson, Andrew

    2017-01-01

    Objective: To investigate the effect of 3-year phased bans of the pesticides dimethoate and fenthion in 2008–2010, and paraquat in 2009–2011, on suicide mortality in Sri Lanka. Methods: Age-standardised overall, sex-specific, and method-specific suicide rates were calculated using Sri Lankan police...... as commencement of the post intervention period. Conclusion: Bans of paraquat, dimethoate and fenthion in Sri Lanka were associated with a reduction in pesticide suicide mortality and in overall suicide mortality despite a small rise in other methods. This study provides further evidence for the effectiveness...

  8. Development of a functionalized polymeric ionic liquid monolith for solid-phase microextraction of polar endocrine disrupting chemicals in aqueous samples coupled to high-performance liquid chromatography.

    Science.gov (United States)

    Feng, Juanjuan; Sun, Min; Bu, Yanan; Luo, Chuannan

    2015-09-01

    Ionic liquids (ILs) have been efficiently used as a "designer sorbent" in sample preparation. A novel 1-(3-aminopropyl)-3-(4-vinylbenzyl)imidazolium 4-styrenesulfonate IL monomer was synthesized and copolymerized with 1,6-di(3-vinylimidazolium) hexane bishexafluorophosphate IL as cross-linking agent to prepare a cross-linked polymeric ionic liquids (PILs) monolith. Coupled to high-performance liquid chromatography (HPLC), the PILs monolith was used as a solid-phase microextraction (SPME) sorbent to extract some polar endocrine disrupting chemical (EDCs) such as estrogens, bisphenol A, and phthalate esters in aqueous samples. Preparation and extraction conditions were investigated and optimized to obtain satisfactory extraction efficiency. Limits of detection (LODs) of the proposed method for three steroid estrogens and bisphenol A were 0.25 and 0.2 μg L(-1), respectively, which were lower than or comparable to some other sample preparation methods. Intra- and inter-day repeatability for all the analytes was 2.2-12%. The monolith-to-monolith repeatability was 7.4-15%. The extraction performance of the method for analysis of target estrogens in treated domestic wastewater was investigated and compared with a dispersive liquid-liquid microextraction (DLLME) method. The proposed SPME method provided better sensitivity and higher resistance to matrix interferences.

  9. The effect of ZnO nanorod growth duration by hydrothermal deposition method to the photovoltaic properties

    Science.gov (United States)

    Ali, Engku Abd Ghapur Engku; Rezali, Roslinda

    2012-11-01

    In this study, the effect of time in hydrothermal method to the growth of ZnO nanorods at low temperature was investigated. The substrate is prepared through three stages which are the seeding stage, the growth stage and the dye sensitized stage. The morphology of the ZnO growth was measured using the Scanning Electron Microscope (SEM). Efficiency was verified by the growth duration of 2, 4 and 8 hours. The current and voltage of the thin films were measured by using two point probes under dark and different light intensity of 10, 20, 50 and 100 Wm-2. The efficiency under light intensity was increased with increasing growth duration. Growth duration of 8 hours combined with Bis(2,2'-bipyridine)-4,4'-dicarboxybipyridine-ruthenium di(N-succinimidyl ester) bis(hexafluorophosphate) and 1-butyl-2,3-dimethylimidazolium chloride thin films on indium tin oxide (ITO) thin films are suitable to increase the efficiency of the device under 100 W/m2 intensity of light which is 1.2 7%.

  10. Catalytic polymeric nanocomposites via cucurbit[n]uril host-guest interactions

    Science.gov (United States)

    Wu, Yuchao; Lan, Yang; Liu, Ji; Scherman, Oren A.

    2015-08-01

    Polymeric nanocomposites were prepared by using cucurbit[7]uril as a `supramolecular anchor', as well as stabilising ligand to immobilise catalytic transition-metal nanoparticles on the surface of methyl viologen-bearing polymeric colloids. This facile and spontaneous supramolecular approach allows for control over size, morphology and composition of the nanocomposites. The small metallic nanoparticles impart the nanocomposites with great potential in catalysis.Polymeric nanocomposites were prepared by using cucurbit[7]uril as a `supramolecular anchor', as well as stabilising ligand to immobilise catalytic transition-metal nanoparticles on the surface of methyl viologen-bearing polymeric colloids. This facile and spontaneous supramolecular approach allows for control over size, morphology and composition of the nanocomposites. The small metallic nanoparticles impart the nanocomposites with great potential in catalysis. Electronic supplementary information (ESI) available. See DOI: 10.1039/C5NR03647J

  11. Evaluation of DNA damage in Chinese toad (Bufo bufo gargarizans) after in vivo exposure to sublethal concentrations of four herbicides using the comet assay.

    Science.gov (United States)

    Yin, Xiao Hui; Li, Shao Nan; Zhang, Le; Zhu, Guo Nian; Zhuang, Hui Sheng

    2008-05-01

    Chinese toad, Bufo bufo gargarizans, is frequently found in rice fields, muddy ponds, wetlands and other aquatic ecosystems in China. Because of its habitat, it has many chances of being exposed to pesticides, such as acetochlor, butachlor, chlorimuron-ethyl, and paraquat, which are extensively used in rice or cereal fields. Amphibians may serve as model organisms for determining the genotoxic effects of pollutants contaminating these areas. In the present study DNA damage was evaluated in the Chinese toad using the comet assay, as a potential tool for the assessment of ecogenotoxicity. The first step was to determine the acute toxicity of the above-mentioned herbicides. In acute tests, tadpoles were exposed to a series of relatively high concentrations of acetochlor, butachlor, chlorimuron-ethyl, and paraquat for 96 h. The LC(50 )(96 h) of acetochlor, butachlor, chlorimuron-ethyl and paraquat were measured as 0.76, 1.32, 20.1 and 164 mg l(-1), respectively. Also, negative effects on the behavior of tadpoles were observed with acetochlor, butachlor, and paraquat. Secondly, the comet assay was used for detecting DNA damage in Chinese toad tadpoles exposed to sublethal concentrations of four herbicides. Significant (P Bufo bufo gargarizans for genotoxicity assessment of herbicides.

  12. Assessment of precautionary measures in agrochemicals usage ...

    African Journals Online (AJOL)

    Assessment of precautionary measures in agrochemicals usage among urban arable crop farmers in Oyo state, Nigeria. ... Ethiopian Journal of Environmental Studies and Management ... The common agrochemicals used by the farmers with their trade names were paraquat, diazinion, weed-off, round-up and premextra.

  13. Akinloye et al (21)

    African Journals Online (AJOL)

    Paraquat, a highly toxic weed killer, was once promoted by the United States for use in Mexico to destroy marijuana plants. Research found that this herbicide was dangerous to workers who applied it to the plants (Robbe et al,. 2004). In agriculture, it is used as an active ingredient in different products for protection of.

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

    African Journals Online (AJOL)

    2010-06-04

    Jun 4, 2010 ... analysed for protein, blood and glucose using urine dipsticks. Furthermore, serum and urinary sodium concentrations were evaluated via flame photometry with the subsequent calculation of fractional excretion of sodium (FENa) and creatinine clearance. Intervention against Paraquat-induced AKI. We have ...

  15. Modulation of Antioxidant Enzyme Expression and Activity by ...

    African Journals Online (AJOL)

    Renal toxicity produced by paraquat involves the generation of reactive oxygen species (ROS) which can overwhelm antioxidant defences, leading to oxidant injury. However, there are conflicting reports regarding the activity and/or expression of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT) ...

  16. 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 ...

  17. Author Details

    African Journals Online (AJOL)

    Tho, Lai-Yeng. Vol 15, No 12 (2016) - Articles Evaluation of neuroprotective properties of two synthetic prenylated xanthone analogues against paraquat and 6- hydroxydopamine toxicity in human neuroblastoma SHSY5Y cells. Abstract PDF. ISSN: 1596-9827. AJOL African Journals Online. HOW TO USE AJOL.

  18. 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 ||

  19. Effect of organic amendments on microbial biomass of a tropical soil ...

    African Journals Online (AJOL)

    Studies were carried out on the impact of organic amendments on microflora of soils treated with 2,4- dichlorophenoxy-acetic acid, atrazine, atrazine + metolachlor and paraquat herbicides applied at one and half doses of the recommended rates. Poultry manure-0.05%, urea-0.1 M and glucose–0.1 M of herbicide-treated ...

  20. THE EFFECT OF TWO PESTICIDES DICHLORVOS AND ...

    African Journals Online (AJOL)

    The data obtained suggest that both pesticides are environmentally unfriendly and should be used with utmost restraint, especially in the aquatic environment where they could be hazardous to both aquatic life and man. KEY WORDS: Dichlorvos, Paraquat, Manifestation, Mortality, Heterobranchus longifilis. Global Jnl Pure ...

  1. Author Details

    African Journals Online (AJOL)

    Oniye, S.J.. Vol 40, No 3 (2015) - Articles Responses of the African catfish Clarias gariepinus to long-term exposure to glyphosate- and paraquat-based herbicides. Abstract. ISSN: 1727-9364. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  2. Journal of Agriculture and Social Research (JASR) - Vol 10, No 2 ...

    African Journals Online (AJOL)

    Profitability and viability analyses of small-holder cocoa production three management systems in Abia State Nigeria: A study for commercialization implications · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT .... Effect of paraquat as post emergence herbicide on yield of cowpea (vigna unguiculata (l) walp).

  3. Development of sunflower oil and composition with respect to seed moisture and physiological maturity

    Science.gov (United States)

    Desiccants/harvest aids are becoming more commonly used to hasten sunflower harvest. The current recommendation is to apply a desiccant (e.g., glyphosate and paraquat) at 35% or less seed moisture at physiological maturity (PM). Desiccating as early as possible without sacrificing yield may be a des...

  4. 1751-IJBCS-Article-Ayantade Ayansina Victor

    African Journals Online (AJOL)

    hp

    days after application at 150 ppm and at 12 days after application at 100 ppm. ... mis-used (ICI, 1978; Alexander, 1995). As a .... Application of 2,4-D resulted in decrease in pH at all concentrations. However, paraquat application resulted in significant increases in the pH values at all levels of concentrations (P<0.05).

  5. 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 ...

  6. Testing pelargonic acid and pyraflufen-ethyl with glyphosate as ...

    African Journals Online (AJOL)

    Testing pelargonic acid and pyraflufen-ethyl with glyphosate as alternatives to paraquat dichloride for the preparation of fire-break tracer lines at Underberg, ... With the exception of Guild (at 0.5 l ha−1), the other herbicides at the rates tested either did not provide effective initial control of the vegetation or they killed the ...

  7. 191-IJBCS-Article-Dr A D V Ayansina

    African Journals Online (AJOL)

    RHUMSIKI

    Studies were carried out on the impact of organic amendments on microflora of soils treated with 2,4- dichlorophenoxy-acetic acid, atrazine, atrazine + metolachlor and paraquat herbicides applied at one and half doses of the recommended rates. Poultry manure-0.05%, urea-0.1 M and glucose–0.1 M of herbicide-treated.

  8. Evaluation of neuroprotective properties of two synthetic prenylated ...

    African Journals Online (AJOL)

    Siong Nga1, ... SH-SY5Y cell death. Methods: SH-SY5Y cells were treated with SX1 and SX2, and the maximum non-toxic dose (MNTD) were obtained by 3-(4 .... incubation of paraquat with vitamin E (positive control for neuroprotection) ...

  9. 77 FR 38632 - Findings of Research Misconduct

    Science.gov (United States)

    2012-06-28

    ..., P30 ES01247, and R01 ES10791 and the intramural program at the National Institute on Drug Abuse (NIDA... the effects of combined exposure of the pesticides paraquat and maneb on dopaminergic neuronal death... that development of Parkinson's disease entails proteasomal dysfunction with a higher effect in males...

  10. Sierra Leone Journal of Biomedical Research Vol. 2 (2) pp. 103-114

    African Journals Online (AJOL)

    Owner

    ABSTRACT. Renal toxicity produced by paraquat involves the generation of reactive oxygen species (ROS) which can overwhelm antioxidant defences, leading to oxidant injury. However, there are conflicting reports regarding the activity and/or expression of antioxidant enzymes such as superoxide dismutase (SOD), ...

  11. 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

  12. Pillar[5]arene-based amphiphilic supramolecular brush copolymer: fabrication, controllable self-assembly and application in self-imaging targeted drug delivery†

    OpenAIRE

    Yu, Guocan; Zhao, Run; Wu, Dan; Zhang,Fuwu; Shao, Li; Zhou, Jiong; Yang, Jie; Tang, Guping; Chen, Xiaoyuan; Huang, Feihe

    2016-01-01

    Supramolecular brush copolymers have attracted continuing interest due to their unusual architectures, fascinating properties, and potential applications in many fields involving smart stimuli-responsive drug delivery systems. Herein, the first pillararene-based amphiphilic supramolecular brush copolymer (P5-PEG-Biotin⊃PTPE) was constructed on the basis of the host–guest molecular recognition between a water-soluble pillar[5]arene (P5) and a viologen salt (M). P5-PEG-Biotin⊃PTPE self-assemble...

  13. How to get the desired reduction voltage in a single framework! Metallacarborane as an optimal probe for sequential voltage tuning.

    Science.gov (United States)

    Tarrés, Màrius; Arderiu, Víctor S; Zaulet, Adnana; Viñas, Clara; Fabrizi de Biani, Fabrizia; Teixidor, Francesc

    2015-07-14

    An appealingly wide set of redox couples ranging from -1.74 to -0.35 V based on a metallabisdicarbollide derivative, [M(C2B9H11-yIy)2](-) (M = Co, Fe), each being distinguished from the former by near 0.15 V and all having the same structure have been demonstrated. The redox active methyl viologen moiety ([MV](2+)) has been used as a benchmark.

  14. Photoresponsive multilayer spiral nanotubes: intercalation of polyfluorinated cationic azobenzene surfactant into potassium niobate.

    Science.gov (United States)

    Tong, Zhiwei; Takagi, Shinsuke; Shimada, Tetsuya; Tachibana, Hiroshi; Inoue, Haruo

    2006-01-25

    The first successful synthesis of photoresponsive multilayer spiral nanotubes by the introduction of polyfluorinate cationic azobenzene derivative, trans-[2-(2,2,3,3,4,4,4-heptafluorobutylamino)ethyl]-{2-[4-(4-hexyphenylazo)-phenoxy]ethyl}dimethylammonium (abbreviated as C3F7-Azo+), into layered niobate interlayer I by a two-step guest-guest exchange method using the intercalation compound, methyl viologen (MV2+)-K4Nb6O17, as precursor is reported.

  15. 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 ...

  16. Comparison of the effects of two herbicides and an insecticide on tropical freshwater plankton in microcosms.

    Science.gov (United States)

    Leboulanger, C; Bouvy, M; Carré, C; Cecchi, P; Amalric, L; Bouchez, A; Pagano, M; Sarazin, G

    2011-11-01

    Natural plankton communities from a tropical freshwater reservoir (Combani Reservoir, Mayotte Island, Mozambique Channel) were exposed, in 20-l nutrient-enriched microcosms, to two nominal concentrations of three pesticides: the herbicides diuron (2.2 and 11 μg/l) and paraquat (10 and 40.5 μg/l) and the insecticide fenitrothion (10 and 100 μg/l), commonly used in the tropics for agriculture and disease vector control. Bacterioplankton, phytoplankton, and zooplankton communities were monitored for 5 days after exposure, and the concentrations of toxicant and major nutrients were measured. Bacterioplankton growth was noticeable in all systems and was slightly affected by pesticide at any concentration. A transitory increase in thymidine-based bacterial production was observed in diuron- and fenitrothion-treated microcosms, followed by a marked decrease in all microcosms after 5 days. The functional diversity of bacterioplankton, evaluated using BIOLOG ECO(®) microplates, was reduced by exposure to the highest pesticide concentrations. Phytoplankton was affected by pesticides in different ways. Chlorophyll biomass and biovolumes were increased by diuron addition and decreased by paraquat, whereas fenitrothion-treated microcosms remained unaffected relative to controls. Phytoplankton taxonomic diversity was decreased by paraquat and high doses of fenitrothion but was unaffected by addition of diuron. The decrease in diversity was due to a reduction in the number of species, whereas the density of small cells increased, especially after addition of paraquat. Heterotrophic flagellates were sensitive to paraquat and to the highest diuron concentration; a reduction in biomass of up to 90% was observed for 40.5 μg/l paraquat. Zooplankton, dominated by Thermocyclops decipiens and Diaphanosoma excisum, was slightly sensitive to diuron, and very sensitive to paraquat. High concentrations of the insecticide fenitrothion were effective only on young stages. The potential

  17. Effect of lung fibrosis on glycogen content in different extrapulmonary tissues.

    Science.gov (United States)

    Borges, Elizabeth Lage; de Barros Pinheiro, Marina; Prata, Luana Oliveira; Sales, Wesley Araújo; Silva, Yuri Augusto Junqueira Belém; Caliari, Marcelo Vidigal; Rodrigues-Machado, Maria Glória; da Glória Rodrigues-Machado, Maria

    2014-02-01

    Patients with pulmonary fibrosis often exhibit reduced lung function and diminished health-related quality of life. Studies have shown that paraquat-induced, extrapulmonary, acute lung injury affects the metabolic profile of glycogen content in different tissues. The purpose of the present study was to investigate whether the process of pulmonary fibrosis induced by continuous exposure to the toxic herbicide paraquat or by a local insult from bleomycin affects the glycogen content in tissues. In the paraquat experiment, Wistar rats (n = 5 per group) received either saline (controls) or an intraperitoneal injection of a paraquat solution (7.0 mg/kg; experimental group) once a week for 4 weeks. In the bleomycin experiment, Balb/c mice (n = 5 per group) received either saline (controls) or 6.25 U/kg of bleomycin through intratracheal instillation in single dose (experimental group). Glycogen content in different tissues (mg/g tissue) was measured using the anthrone reagent. The lungs submitted to histopathological and quantitative analyses of fibrosis. Paraquat-induced fibrosis led to lower glycogen content in the gastrocnemius muscle (2.7 ± 0.1 vs. 3.4 ± 0.1; 79 %) compared with the controls, whereas no changes in glycogen content were found in the diaphragm or heart. Bleomycin-induced fibrosis led to lower glycogen content in the diaphragm (0.43 ± 0.02 vs. 0.79 ± 0.09, 54 %), gastrocnemius muscle (0.62 ± 0.11 vs. 1.18 ± 0.06, 52 %), and heart (0.68 ± 0.11 vs. 1.39 ± 0.1, 49 %) compared with the controls (p < 0.05). Moreover, the area of fibrous connective tissue (μm(2)) in the lungs was significantly increased in paraquat-induced fibrosis (3,463 ± 377 vs. 565 ± 89) and bleomycin-induced fibrosis (3,707 ± 433.9 vs. 179 ± 51.28) compared with the controls. The findings suggest that the effects of fibrogenesis in the lungs are not limited to local alterations but also lead to a reduction in glycogen content in the heart

  18. Chemical induction of resinosis in southern pines. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Stubbs, J.; Outcalt, K.W.

    1982-01-01

    Research studies in the use of paraquat, a contact herbicide, for lightwood induction; i.e., the accumulation of oleoresin in the boles of living southern pine trees are summarized. The objectives of this research were to determine oleoresin yields as influenced by treatment factors, to estimate treatment costs, to uncover technical problems, both in the field and processng plants, and to assess the problem of bark beetle attacks on treated trees. Two pulp and paper mill trials using paraquat-treated wood were conducted, one with loblolly and one with slash pine. The loblolly trial yielded 40 percent more tall oil, or an extra 27.2 pounds/cord of wood. Due to limited turpentine condenser capacity, no additional turpentine was recovered. However, there is evidence to believe that an additional one gal./cord could have been realized.

  19. 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

  20. Simultaneous adsorption/desorption of quaternary ammonium herbicides by acid vineyard soils

    Science.gov (United States)

    Conde Cid, Manuel; Paradelo Núñez, Remigio; Fernández Calviño, David; Nóvoa Muñoz, Juan Carlos; Arias Estévez, Manuel

    2017-04-01

    Competitive adsorption and desorption of three quaternary ammonium herbicides (paraquat, diquat, and difenzoquat) have been studied in four sandy-loam acid vineyard soils from NW Spain and Portugal. The soils present organic matter contents between 3 and 48 g kg-1 and copper contents ranging from 25 to 107 mg kg-1. Adsorption has been studied under equilibrium conditions in batch experiments, and kinetics were studied in a stirred-flow chamber. Adsorption and desorption followed a Freundlich model and kinetics were well described by the pseudo-first-order model. The retention capacity for the pesticides by the four soils followed the sequence: paraquat > diquat > difenzoquat. The different adsorption capacities of each soil were not related to pH, clay or organic matter contents, as could be expected, but rather to soil copper content. The results show that competition with copper for adsorption sites is an important factor in quaternary ammonium herbicides retention in soils with these characteristics.

  1. 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.

  2. 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...

  3. Download this PDF file

    African Journals Online (AJOL)

    USER

    2016-11-17

    Nov 17, 2016 ... 37.5 percent used rodeo, 84.2 percent used Weed-off and 59.2 percent used force-up while about 85.0 percent used. Paraquat. In addition, 60.0 percent of the respondents used Round-up, 77.5 percent used Glyphosate, 55.8 percent used. Sorosate, 20.0 percent used touch-down,. 35.0 percent used ...

  4. Evaluation of Basta ( glufosinate ammonium ) for weed control in ...

    African Journals Online (AJOL)

    Basta at the rate of 0.6 - 1.0 kg a.i./ha effectively controlled most of the weeds found in coffee growing areas of Ghana, over much longer periods than the use of paraquat at the rate of 0.3 - 0.6 kg a.i./ha. However both herbicides could not effectively suppress perennial weeds such as Imperata cylindrica, Panicum maximum, ...

  5. 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.

  6. 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.

  7. 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.

  8. Comparative effects of pesticides on in vivo dopamine release in freely moving rats.

    Science.gov (United States)

    Faro, Lilian R F; Alfonso, Miguel; Cervantes, Rosa; Durán, Rafael

    2009-12-01

    The effects of different types of pesticides on the in vivo striatal dopamine release were investigated by using in vivo brain microdialysis technique. MPTP, paraquat, maneb, dicofol, DDT, lindane and flutriafol (1 mM) were administered directly into the striatum, and levels of dopamine and its metabolites dihydroxyphenylacetic acid (DOPAC) and homovallinic acid (HVA) were measured using HPLC-EC. Intrastriatal administration of pesticides induced the following maximal effects on the dopamine levels: maneb 791 +/- 87%, dicofol 101 +/- 1%, DDT 779 +/- 32%, paraquat 956 +/- 80%, lindane 281 +/- 28% and flutriafol 218 +/- 51% with respect to basal levels. Infusion of pesticides also produced alterations in extracellular DOPAC and HVA levels. A comparative scale of potency was developed to estimate the relative potency of pesticides to induce striatal dopamine release in vivo, using the same concentration and experimental conditions. According to this comparative scale of potency, paraquat is 10 times more potent (in a scale of 10) than dicofol, which did not induce any effect on dopamine release. The second more potent pesticide is maneb, followed by DDT, the organochlorine which has the highest potential to produce alterations on dopaminergic neurotransmission; flutriafol and the organochlorine lindane produced moderate increases in dopamine levels. These results suggest that different classes of pesticides, with different structures and biochemical activities, may affect the striatal dopaminergic system differently, inducing neurotoxicity.

  9. 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.

  10. Fuel plantation research. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Stubbs, J.

    1977-08-01

    Research in chemical induction of lightwood is summarized. Four large-scale proof of concept studies have been installed that test five paraquat treatments on a total of 71,228 trees. This wood will be used in actual pulp mill and extraction plant runs to determine oleoresin recovery and possible processing problems. Nearly 3,000 wood samples have been collected to ascertain duration of treatment effects. Results of complementary studies are also reported; most of these are concerned with optimization of paraquat application techniques and the effect of species differences on these methods. A large study was installed to field screen selected insecticides for insect pest control in lightwood operations, and interim results are presented. Dowco 214 (Reldon) proved to be an adequate substitute for BHC and 0.5% concentrations were as effective as 1%. Ten northern and seven western conifer species were tested for their reaction to paraquat treatment. All members of genus Pinus showed appreciable resin soaking but other coniferous genera did not. Feasibility of oleoresin substitution for petrochemicals was investigated.

  11. Photoinitiated ion movements in bilayer membranes containing magnesium octaethylporphyrin.

    Science.gov (United States)

    Woodle, M C; Mauzerall, D

    1986-09-01

    A photocurrent produced by planar lipid bilayers containing Mg-octaethylporphyrin in the presence of oxygen has been investigated to determine if the current is due to movement of the MgOEP+ ion in the bilayer. Photoexcitation of the MgOEP is known to produce MgOEP+ in the bilayer when an electron acceptor is present. However, the aqueous electron acceptors ferricyanide and methyl viologen (MV+2) have opposite effects on the photocurrent. Ferricyanide decreases the photo current, even in the presence of oxygen, whereas methyl viologen increases the photocurrent, but only when oxygen is present. We attribute most of the photocurrent to the movement of superoxide anion. The difference in effect between ferricyanide and methyl viologen is attributed to the different rates of reduction of O2 by reduced MV+ (fast) vs. ferrocyanide (slow) and the known competition between ferricyanide and oxygen as the acceptor for the photoexcited porphyrin. It is inferred that most of the MgOEP is localized in the polar region of the lipid bilayer. Addition of ferrocyanide to the aqueous phase on one side of the bilayer, to trap MgOEP+ produced on the other side by MV+2, fails to increase the lifetime of the photovoltage. With a pH gradient across the bilayer, we observed only 5% of the photovoltage expected for the selective transport of H+ or OH- by MgOEP+. Thus, these measurements set the lower limit for the cross bilayer transit time of MgOEP+ or its charge in the range of 0.1-0.5 s.

  12. 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.

  13. 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

  14. [Fundamental studies in oxidation-reduction in relation to water photolysis]. Final report, February 15, 1990--July 31, 1993

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, J.K.

    1994-07-01

    Broad objectives are to improve the conceptual view of ways in which membranes and interfaces can be used to control chemical reactivity. Focus was on three elementary processes central to developing membrane-based integrated chemical systems for water photolysis or related photoconversion/photostorage processes. It was sought to identify the influence of interfaces on charge separation/recombination reactions, pathways for transmembrane charge separation across hydrocarbon bilayer membranes, and mechanisms of water oxidation catalyzed by transition metal coordination complexes. The supramolecular assemblies studied comprise primarily small unilamellar vesicles doped with amphiphilic viologens (N,N`dialkyl-4,4`-bipyridinium ions) which can function as transmembrane charge relays.

  15. 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)

  16. Both Hsp70 chaperone and Clp protease plastidial systems are required for protection against oxidative stress.

    Science.gov (United States)

    Pulido, Pablo; Llamas, Ernesto; Rodriguez-Concepcion, Manuel

    2017-03-04

    Environmental stress conditions such as high light, extreme temperatures, salinity or drought trigger oxidative stress and eventually protein misfolding in plants. In chloroplasts, chaperone systems refold proteins after stress, while proteases degrade misfolded and aggregated proteins that cannot be refolded. We observed that reduced activity of chloroplast Hsp70 chaperone or Clp protease systems both prevented growth of Arabidopsis thaliana seedlings after treatment with the oxidative agent methyl viologen. Besides showing a role for these particular protein quality control components on the protection against oxidative stress, we provide evidence supporting the existence of a yet undiscovered pathway for Clp-mediated degradation of the damaged proteins.

  17. 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.

  18. Artificial control of nitrate respiration through the lac promoter permits the assessment of oxygen-mediated posttranslational regulation of the nar operon in Pseudomonas aeruginosa.

    Science.gov (United States)

    Noriega, Chris E; Sharma, Vandana; Rowe, John J

    2007-09-01

    In this study, oxygen and nitrate regulation of transcription and subsequent protein expression of the unique narK1K2GHJI respiratory operon of Pseudomonas aeruginosa were investigated. Under the control of PLAC, P. aeruginosa was able to transcribe nar and subsequently express methyl viologen-linked nitrate reductase activity under aerobic conditions without nitrate. Modulation of PLAC through the LacI repressor enabled us to assess both transcriptional and posttranslational regulation by oxygen during physiological whole-cell nitrate reduction.

  19. Hydrogenase in actinorhizal root nodules and root nodule homogenates.

    Science.gov (United States)

    Benson, D R; Arp, D J; Burris, R H

    1980-04-01

    Hydrogenases were measured in intact actinorhizal root nodules and from disrupted nodules of Alnus glutinosa, Alnus rhombifolia, Alnus rubra, and Myrica pensylvanica. Whole nodules took up H2 in an O2-dependent reaction. Endophyte preparations oxidized H2 through the oxyhydrogen reaction, but rates were enhanced when hydrogen uptake was coupled to artificial electron acceptors. Oxygen inhibited artifical acceptor-dependent H2 uptake. The hydrogenase system from M. pensylvanica had a different pattern of coupling to various electron acceptors than the hydrogenase systems from the alders; only the bayberry system evolved H2 from reduced viologen dyes.

  20. Hollow mesoporous raspberry-like colloids with removable caps as photoresponsive nanocontainers

    OpenAIRE

    Hu, Chi; West, Kevin R.; Scherman, Oren A.

    2016-01-01

    This is the author accepted manuscript. The final version is available from the Royal Society of Chemistry via https://doi.org/10.1039/C6NR01016D The fabrication, characterisation and controlled cargo release of hollow mesoporous raspberry-like colloids (HMRCs), which are assembled by utilising host-guest complexation of cucurbit[8]uril (CB[8]) are described. CB[8] is employed as a supramolecular linker to ‘stick’ the viologen functionalised paramagnetic iron oxide nanoparticles onto an az...

  1. Aqueous electrolytes for redox flow battery systems

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. 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

  3. Encapsulation of Solitary Dye Molecules in Silica Nanoshells

    Science.gov (United States)

    Levinger, Nancy E.; Langdon, Benjamin

    2000-03-01

    We report on the encapsulation of solitary coumarin 343 dye molecules within hollow silica nanospheres. Through steady-state and time-resolved spectroscopy, we demonstrate that the dye molecule is isolated from bulk solution. The fluorescence lifetime of the dye is dramatically shortened and non-single exponential. Fluorescence quenching shows that the encapsulated dye is unaffected by the presence of the methyl viologen quencher. Time resolved fluorescence anisotropy shows that the encapsulated dye does not move freely as it does in bulk solution. Interpretation of the results will be presented.

  4. Phenytoin-initiated hydroxyl radical formation: characterization by enhanced salicylate hydroxylation.

    Science.gov (United States)

    Kim, P M; Wells, P G

    1996-01-01

    Bioactivation of phenytoin and related teratogens by peroxidases such as prostaglandin H synthase (PHS) may initiate hydroxyl radical (.OH) formation that is teratogenic. Salicylate is hydroxylated by .OH at the third and fifth carbon atoms, forming 2,3- and 2,5-dihydroxybenzoic acids (DHBA). In vivo salicylate metabolism produces only the 2,5-isomer, so 2,3-DHBA formation may reflect .OH production. In the present study, we validated the salicylate assay using the known .OH generator paraquat and evaluated .OH production by phenytoin. Female CD-1 mice were treated with paraquat (30 mg/kg, intraperitoneally) given 30 min after acetylsalicylic acid (ASA) (200 mg/kg, intraperitoneally). Blood was collected at 5, 15, and 30 min and 1 and 2 hr after paraquat, and plasma was analyzed for DHBA isomers and glucuronide conjugates by high performance liquid chromatography with electrochemical detection. Paraquat increased 2,3-DHBA formation 19.2-fold, with substantial inter-individual variability in the time of maximal formation (p = 0.0001). The 2,3-DHBA glucuronide conjugates in vivo and in hepatic microsomal studies amounted to approximately 11% and 0.43%, respectively, of total 2,3-DHBA equivalents. To investigate putative .OH production initiated via PHS-catalyzed phenytoin bioactivation, ASA was given 30 min before phenytoin (65 or 100 mg/kg, intraperitoneally), resulting in respective 7.6-fold (p = 0.02) and 14.2-fold (p = 0.003) increases in phenytoin-initiated maximal 2,3-DHBA formation. Maximal 2,3-DHBA formation was 2.1-fold higher when ASA was administered after rather than before the same dose (65 mg/kg) of phenytoin (p = 0.03), indicating ASA inhibition of PHS-catalyzed phenytoin bioactivation. Urinary analysis was much less sensitive, and the 2,5-isomer reflected enzymatic rather than .OH-mediated hydroxylation. The paraquat studies demonstrate the importance of timing in accurately quantifying 2,3-DHBA formation and suggest that glucuronidation does not

  5. Biocompatible pillararene-assembly-based carriers for dual bioimaging.

    Science.gov (United States)

    Zhang, Huacheng; Ma, Xing; Nguyen, Kim Truc; Zhao, Yanli

    2013-09-24

    Present research provides a successful example to use biocompatible pillararene-based assemblies for delivering mixed dyes in dual bioimaging. A series of tadpole-like and bola amphiphilic pillararenes 1-4 were synthesized by selectively employing water-soluble ethylene glycols and hydrophobic alkyl units as the starting materials. In comparison with their monomers, these amphiphilic pillararenes not only show improved biocompatibility to cells but also could form homogeneous supramolecular self-assemblies. Interestingly, different types of amphiphilic pillararene-based assemblies exhibit various performances on the delivery of dyes with different aqueous solubility. All assemblies can deliver water-soluble rhodamine B to cells, while only tadpole-like amphiphilic pillararene-based assemblies performed better on delivering hydrophobic fluorescein isothiocyanate for imaging. In addition, pillararene derivatives 1, 3, and 4 could complex with a viologen guest, further forming stable assemblies for bioimaging. In such cases, the assembly formed from the complex of tadpole-like amphiphile pillararene 1 with the viologen guest performed better in delivering mixed dyes. Finally, an anticancer drug, doxorubicin, was successfully delivered to cells by using the pillararene-based assemblies. The current research has determined the capacities of pillararene-based assemblies to deliver different dyes for bioimaging and paves the way for using these biocompatible carriers toward combined cancer therapy.

  6. Solute partitioning in aqueous surfactant assemblies: comparison of hydrophobic-hydrophilic interactions in micelles, alcohol-swollen micelles, microemulsions, and synthetic vesicles

    Energy Technology Data Exchange (ETDEWEB)

    Russell, J.C.; Whitten, D.G.

    1982-11-03

    The structures of anionic assemblies including sodium lauryl sulfate (SLS) micelles, alcohol-swollen SLS micelles, microemulsions, and vesicles of a mixture of dipalmitoyllecithin and dicetyl phosphate are investigated by using the ground-state complexation of a hydrophilic quencher (methyl viologen) with several hydrophobic fluorescent probes, including surfactant stilbenes and 1,4-diphenylbutadiene. In SLS micelles this complexation can be decreased nearly an order of magnitude by addition of 1-heptanol, indicating that the structure of the micelle can be adjusted from the highly open structure of the pure micelle to a much more closed structure in which hydrophobic solubilizates can be sequestered from hydrophilic reagents bound to the surface. The fluorescence quenching process in anionic vesicles is strongly dependent on temperature; at low temperatures quenching occurs, while at higher temperatures addition of methyl viologen appears to increase the stilbene fluorescence, indicating that the dicationic quencher binds to the vesicle surface, increasing the order of the system. These results indicate that the degree of organization of surfactant systems can be adjusted by simple changes in composition. 33 references.

  7. A Simple Approach to Fabricate an Efficient Inverted Polymer Solar Cell with a Novel Small Molecular Electrolyte as the Cathode Buffer Layer.

    Science.gov (United States)

    Kim, Youn Hwan; Sylvianti, Nadhila; Marsya, Mutia Anissa; Park, Juyun; Kang, Yong-Cheol; Moon, Doo Kyung; Kim, Joo Hyun

    2016-12-07

    A novel small-molecule electrolyte, 1,1'-bis(4-hydroxypropyl)-[4,4'-bipyridine]-1,1'-diium bromide (V-OH), containing a mixture of PTB7:PC71BM has been designed and synthesized as a cathode buffer layer for inverted polymer solar cells (iPSCs). The molecular structure of this new compound comprises a viologen skeleton with hydroxyl group terminals. While the viologen unit is responsible for generating a favorable interface dipole, the two terminal hydroxyl groups of V-OH may generate a synergy effect in the magnitude of the interface dipole. Consequently, the devices containing the V-OH interlayer exhibited a power conversion efficiency (PCE) of 9.13% (short circuit current = 17.13 mA/cm2, open circuit voltage = 0.75 V, fill factor = 71.1%). The PCE of the devices with V-OH exhibited better long-term stability compared to that of the devices without V-OH. Thus, we found that it is possible to enhance the efficiency of PSCs by a simple approach without the need for complicated methods of device fabrication.

  8. 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.

  9. Purification and characterization of the oxygen-thermostable hydrogenase from the aerobic hyperthermophilic archaeon Aeropyrum camini.

    Science.gov (United States)

    Nishimura, Hiroshi; Sako, Yoshihiko

    2009-10-01

    Aeropyrum camini that was isolated from a deep-sea hydrothermal vent chimney, possessed two hydrogenases (161 and 85 kDa) in its soluble fraction. The 85-kDa hydrogenase was purified to homogeneity using several chromatography columns. The specific activities of the purified hydrogenase were: 14.8 micromol methyl viologen(ox)/mg/min for hydrogen oxidation, and 14.6 micromol methyl viologen(red)/mg/min for proton reduction. The oxygen stabilities of hydrogenases that were purified from A. camini and the hydrogen thermophilic bacterium Persephonella hydrogeniphila, were compared. The hydrogenase purified from P. hydrogeniphila completely lost its activity following a 96-h exposure to atmosphere; however, the A. camini hydrogenase maintained 75% of its initial activity, even after a 168 h of atmospheric exposure. A. camini hydrogenase showed a half-life of 48 h at 90 degrees C, while P. hydrogeniphila hydrogenase showed complete denaturation after a 30 min incubation at the same temperature. Nine residues of the N-terminal amino acid sequence of A. camini hydrogenases (MARLLMIPGT) correspond to the protein sequence encoded by the hypothetical soluble hydrogenase subunit gene (APE2423) from A. pernix strain K1. A. camini hydrogenase has a high thermostability and is very tolerant to oxygen; therefore, it may be used for actual H(2) production.

  10. Temperature dependence of an abiotic glucose/air alkaline fuel cell

    Science.gov (United States)

    Orton, Dane; Scott, Daniel

    2015-11-01

    The temperature dependence of a previously developed glucose fuel cell is explored. This cell uses a small molecule dye mediator to transport oxidizable electrons from glucose to a carbon felt anode. This reaction is driven by an air breathing MnO2 cathode. This research investigates how the temperature of the system affects the power production of the fuel cell. Cell performance is observed using either methyl viologen, indigo carmine, trypan blue, or hydroquinone as a mediator at temperatures of 15, 19, 27, 32, 37, 42, and 49 °C. Cyclic voltammetry of the cell anode at the given temperatures with the individual dyes is also presented. The highest power production amongst all of the cells occurs at 32 °C. This occurs with the mediator indigo carmine or with the mediator methyl viologen. These sustained powers are 2.31 mW cm-2 and 2.39 mW cm-2, respectively. This is approximately a 350% increase for these cells compared to their power produced at room temperature. This dramatic increase is likely due to increased solubility of the mediator dye at higher temperatures.

  11. 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

  12. Resistência de azevém (Lolium multiflorum ao herbicida glyphosate Resistance of italian ryegrass (Lolium multiflorum to glyphosate

    Directory of Open Access Journals (Sweden)

    E.S. Roman

    2004-06-01

    Full Text Available O azevém é uma gramínea de ciclo anual, constituindo-se com freqüência em planta infestante em lavouras de trigo do Rio Grande do Sul. Em experimentos realizados em casa de vegetação e no campo, foi avaliada a suscetibilidade de dois biótipos de azevém ao herbicida glyphosate, bem como a eficiência de herbicidas de ação total na dessecação de Lolium multiflorum para a semeadura direta de trigo. O delineamento experimental foi completamente casualizado em casa de vegetação e de blocos ao acaso em campo, com três e quatro repetições, respectivamente. Foram avaliados herbicidas com mecanismos de ação distintos em diferentes doses: glyphosate, glufosinate, clethodim, haloxyfop-r e diclofop, paraquat e paraquat + diuron. Os resultados, em casa de vegetação, evidenciam que o biótipo sensível é totalmente controlado com glyphosate na dose de 360 g e.a. ha-1 e que doses de até 1.440 g e.a. ha-1 não afetam significativamente o acúmulo de matéria seca do biótipo resistente e produzem toxicidade inferior a 15% sobre este. Já as doses entre 1.440 e 5.760 g e.a. ha-1 de glyphosate reduzem significativamente a produção de matéria seca e resultam em toxicidade inferior a 45%. Em campo, os melhores controles de azevém foram propiciados pelos tratamentos clethodim (79,2 g ha-1 e diuron + paraquat (300 + 600 g ha-1, que não diferiram entre si. Assim, evidencia-se que a população de Lolium multiflorum avaliada neste trabalho é constituída predominantemente de um biótipo resistente aos herbicidas inibidores da enzima EPSPs.Italian ryegrass (Lolium multiflorum is cultivated as forage and/or cover crop in no-till system. However, it is also a serious weed in wheat and other winter cereals in Southern Brazil. Experiments were conducted at greenhouse and field conditions to evaluate the susceptibility of two ryegrass biotype to glyphosate as well as the efficacy of other herbicides on the post-emergence control of the species

  13. Apple polyphenols extend the mean lifespan of Drosophila melanogaster.

    Science.gov (United States)

    Peng, Cheng; Chan, Ho Yin Edwin; Huang, Yu; Yu, Hongjian; Chen, Zhen-Yu

    2011-03-09

    Apple polyphenols (AP) are an excellent source of dietary antioxidants. The present study investigated the effect of AP on the lifespan of fruit flies and their interaction with gene expressions of superoxide dismutase (SOD), catalase (CAT), methuselah (MTH), Rpn11, and cytochrome c oxidase (CcO) subunits III and VIb. Results showed the mean lifespan was significantly extended by 10% in fruit flies fed the AP diet. This was accompanied by up-regulation of genes SOD1, SOD2, and CAT and down-regulation of MTH in the aged fruit flies. Paraquat and H(2)O(2) challenge tests demonstrated that AP prolonged the survival time only for Oregon R wild type flies but not for SOD(n108) or Cat(n1) mutants, in which either SOD or CAT was knocked out. Chronic paraquat exposure could shorten the maximum lifespan from 68 to 31 days and reduce the climbing ability by 60%, whereas AP could partially reverse the paraquat-induced mortality and decline in climbing ability. AP could up-regulate Rpn11 at day 30, whereas it appeared to have no significant effect on gene expression of ubiquitinated protein, CcO subunits III and VIb. These AP-induced changes were unlikely associated with caloric restriction as the gustatory assay found no difference in average body weight and stomach redness index between the control and AP fruit flies. It was therefore concluded that the antiaging activity of AP was, at least in part, mediated by its interaction with genes SOD, CAT, MTH, and Rpn11.

  14. 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

  15. Bioassays for the detection of chemicals that can form bioactivation-dependent reactive free radicals

    Energy Technology Data Exchange (ETDEWEB)

    Sanderson, J.T.; Commandeur, J.N.M.; Wezel, A. van; Vermeulen, N.P.E. (Free Univ. of Amsterdam (Netherlands). Div. of Molecular Toxicology National Inst. for Coastal and Marine Management, Den Haag (Netherlands))

    1999-06-01

    In vitro bioassays were developed for the detection of chemicals that can be bioactivated to reactive free radical species in microsomal fractions. Two methods were deployed, a down-scaled spectrophotometric method for the detection of chemicals that can cause lipid peroxidation using the measurement of thiobarbituric acid-reactive substances (TBARS) and a fluorometric method for the detection of chemicals that can undergo redox cycling to generate superoxide radicals based on the detection of hydrogen peroxide. The response of these systems to prototypical and environmentally relevant chemicals, including tetrachloromethane and paraquat, was examined. The detection limit of the lipid peroxidation bioassay, based on the formation of TBARS, was about 1 [micro]M for tetrachloromethane; that of the bioassay for redox cyclers, based on the production of hydrogen peroxide, was about 2 [micro]M for paraquat and about 100-fold lower for the potent redox cycler 2,3,5,6-tetramethylbenzoquinone (TMBQ). Several binary mixtures of chemicals were tested for potential nonadditive effects in both in vitro systems. Some antagonistic effects among halogenated methanes were observed in the lipid peroxidation assay. In the hydrogen peroxide production assay, greater than additive effects were seen between small concentrations of paraquat and TMBQ. A number of surface water concentrates from several locations in The Netherlands, with various levels of chemical contamination, exhibited a weak response in the hydrogen peroxide production assay. Acetone was found to interfere with the response of the bioassay to redox cyclers and, therefore, the water concentrates (originally in acetone) were transferred to ethanol prior to testing. A good correlation was observed between the response of the water concentrates in the hydrogen peroxide production assay and their acute toxicity in Daphnia magna. No correlation was observed between this bioassay response and toxicity in the Microtox

  16. Dessecação química em pré-colheita da mamona

    Directory of Open Access Journals (Sweden)

    José Salvador Simoneti Foloni

    2011-10-01

    Full Text Available A mamona (Ricinus communis tem hábito de crescimento indeterminado, com expressiva desuniformidade de maturação dos grãos, o que dificulta sobremaneira a colheita mecanizada. O objetivo deste trabalho foi avaliar a eficiência do herbicida glifosato, isolado, ou, em mistura com 2,4-D, e também do paraquat, na dessecação em pré-colheita da mamona. Foram realizados dois experimentos de campo, no delineamento em blocos ao acaso, com quatro repetições, em Rancharia-SP, de março a setembro de 2005. No experimento 1, avaliou-se a mistura de doses de 2,4-D e de glifosato, e no experimento 2 a dessecação somente com paraquat. Foi determinado o teor de água da parte aérea de plantas de mamona em diferentes dias após a aplicação (DAA. A dessecação da mamona com a mistura de 2,4-D e glifosato tem efeito somente a partir de 20 DAA. O 2,4-D aplicado isoladamente tem expressiva capacidade de desidratação do dossel vegetal, porém, inferior à da mistura de 2,4-D e glifosato. A melhor dessecação é com 1,34 kg ha-1 de 2,4-D mais 1,42 kg ha-1 de glifosato. A dose de 1,2 kg ha-1 de paraquat reduz expressivamente o teor de água das plantas da mamona, porém, com desempenho inferior ao da mistura de 2,4-D e glifosato.

  17. Presentations of patients of poisoning and predictors of poisoning-related fatality: Findings from a hospital-based prospective study

    Directory of Open Access Journals (Sweden)

    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.

  18. Inhibition of TDP-43 accumulation by bis(thiosemicarbazonato-copper complexes.

    Directory of Open Access Journals (Sweden)

    Sarah J Parker

    Full Text Available Amyotrophic lateral sclerosis (ALS is a progressive, fatal, motor neuron disease with no effective long-term treatment options. Recently, TDP-43 has been identified as a key protein in the pathogenesis of some cases of ALS. Although the role of TDP-43 in motor neuron degeneration is not yet known, TDP-43 has been shown to accumulate in RNA stress granules (SGs in cell models and in spinal cord tissue from ALS patients. The SG association may be an early pathological change to TDP-43 metabolism and as such a potential target for therapeutic intervention. Accumulation of TDP-43 in SGs induced by inhibition of mitochondrial activity can be inhibited by modulation of cellular kinase activity. We have also found that treatment of cells and animal models of neurodegeneration, including an ALS model, with bioavailable bis(thiosemicarbazonatocopper(II complexes (Cu(II(btscs can modulate kinase activity and induce neuroprotective effects. In this study we examined the effect of diacetylbis(-methylthiosemicarbazonatocopper(II (Cu(II(atsm and glyoxalbis(-methylthiosemicarbazonatocopper(II (Cu(II(gtsm on TDP-43-positive SGs induced in SH-SY5Y cells in culture. We found that the Cu(II(btscs blocked formation of TDP-43-and human antigen R (HuR-positive SGs induced by paraquat. The Cu(II(btscs protected neurons from paraquat-mediated cell death. These effects were associated with inhibition of ERK phosphorylation. Co-treatment of cultures with either Cu(II(atsm or an ERK inhibitor, PD98059 both prevented ERK activation and blocked formation of TDP-43-and HuR-positive SGs. Cu(II(atsm treatment or ERK inhibition also prevented abnormal ubiquitin accumulation in paraquat-treated cells suggesting a link between prolonged ERK activation and abnormal ubiquitin metabolism in paraquat stress and inhibition by Cu. Moreover, Cu(II(atsm reduced accumulation of C-terminal (219-414 TDP-43 in transfected SH-SY5Y cells. These results demonstrate that Cu(II(btsc complexes

  19. Dmp53, basket and drICE gene knockdown and polyphenol gallic acid increase life span and locomotor activity in a Drosophila Parkinson's disease model

    OpenAIRE

    Hector Flavio Ortega-Arellano; Marlene Jimenez-Del-Rio; Carlos Velez-Pardo

    2013-01-01

    Understanding the mechanism(s) by which dopaminergic (DAergic) neurons are eroded in Parkinson's disease (PD) is critical for effective therapeutic strategies. By using the binary tyrosine hydroxylase (TH)-Gal4/UAS-X RNAi Drosophila melanogaster system, we report that Dmp53, basket and drICE gene knockdown in dopaminergic neurons prolong life span (p < 0.05; log-rank test) and locomotor activity (p < 0.05; χ² test) in D. melanogaster lines chronically exposed to (1 mM) paraquat (PQ, oxid...

  20. 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 ......, the preferred position of the cyclic acceptor 7 in the catenanes around either the pyrrolo-annelated TTF or around the hydroquinone donor relies on a fine balance between all the individual noncovalent forces acting in cooperation....

  1. Appraisal of some methods of weed control during initial ...

    African Journals Online (AJOL)

    le champ était supérieure (P £ 0.05 ) dans les lots qui étaient complètement désherbés 2 ou 4 fois/an ou traités avec le paraquat 4 fois/an que dans les lots qui étaient entaillés 2 ou 4 fois/an. Il y avait de nombreuses preuves qui laissent penser que les traitements qui assuraient un environnement sans mauvaise herbe pour ...

  2. Pesticides: Need to Enhance FDA’s (Food and Drug Administration’s) Ability to Protect the Public from Illegal Residues.

    Science.gov (United States)

    1986-10-01

    Metiram 2-3 Paraq iJat -5-6- Pentachlorophenol __ə 2,4,5-T ə ’. Silvex < Thiophanate - methyl ə Zineb 1-2 ’S Class Ill Chloroxuron ə Cyhexatin ə...class I 355 MCPA, Silvex 269 Benomyl and thiophanate - methyl 227 2,4-D and 2,4,5-T 198 Methyl bromide 145 Cyhexatin 137,,0 Daminozide 125 Paraquat 87...districts were instructed to analyze some samples for pesticides such as malathion, aldicarb, carbofuran, synthetic pyrethroids, benomyl, and thiophanate

  3. Hepatotoxicity and Drug/Chemical Interaction Toxicity of Nanoclay Particles in Mice

    Science.gov (United States)

    Isoda, Katsuhiro; Nagata, Ryutaro; Hasegawa, Tomoya; Taira, Yuichiro; Taira, Ikuko; Shimizu, Yoshimi; Isama, Kazuo; Nishimura, Tetsuji; Ishida, Isao

    2017-03-01

    Nanomaterials are relatively new and unconventional materials with many useful properties, but their effects on biological systems are poorly understood. Nanoclay is a general term for layered mineral silicate nanoparticles that are ideally suited for use in clay-based nanocomposites. The potential biological hazards of nanoclays have not been addressed, however. Therefore, we investigated the in vivo effects and drug interactions of nanoclays. In mice, administration of nanoclay particles via the tail vein led to acute liver injury. Co-administration of nanoclay and carbon tetrachloride, paraquat, or cisplatin resulted in both liver and kidney injury. Our findings thus indicate that nanoclay particles are potentially hepato- and nephrotoxic.

  4. モクザイ ノ エネルギー ヘンカン ニ カンスル ケンキュウ 2 パラコート ショリザイ ノ セイユ ジュシ セイセイ ニ オヨボス キセツ ヘンカ ノ エイキョウ

    OpenAIRE

    城代, 進; 真柄, 謙吾; 後藤, 輝男

    1985-01-01

    In order to elucidate the effects of seasonal variations and tree age on the production of essential oil, resin from treated wood, chemical composition, and calorific value of treated wood, the investigation was conducted for paraquat-treated Japanese red pine (Pinus densiflora S. et Z.). The main results are as follows :1) Maximum figures of resin content ratio were showed at Augst and the content of resin was 32% on 5years old tree.2) The production of acidic components and abietic acid i...

  5. Efecto de la aplicación de desecantes sobre la calidad de semillas de garbanzo (Cicer arietinum L.)

    OpenAIRE

    Baricco, Juan Ignacio

    2015-01-01

    Trabajo Final (Especialización en Producción de Cultivos Extensivos)--UNC- Facultad de Ciencias Agropecuarias, 2015. Los productos comúnmente utilizados como desecantes en garbanzo (Cicer arietinum L.) son herbicidas de contacto (Paraquat) y/o sistémicos (Glifosato), sin embargo existen opiniones encontradas acerca de las consecuencias que podrían tener en el potencial fisiológico de la semilla. El objetivo de este trabajo es determinar el efecto de la aplicación de desecantes sobre la cal...

  6. 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

  7. Fabrication, electrochemical and electrocatalytic properties of carbon nanotube@nano-SiO2BenV/phosphomolybdic acid polynary nanocomposite materials

    Science.gov (United States)

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

    2017-06-01

    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-SiO2), viologens, and/or phosphomolybdic acid (PMA), in which the MWNTP4VP, nano-SiO2, 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% nanoSiO2, 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-SiO2BenV particles were strongly attached to the MWNTP4VP surfaces to form MWNTP4VP@nano-SiO2BenV triad nano-cores. Cyclic voltammograms of the MWNTP4VP@nano-SiO2BenV 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-SiO2BenV2+ ↔ MWNTP4VP@nano-SiO2BenV+rad and their dimers. Further, three couples of redox waves were recorded for the casting films of MWNTP4VP@nano-SiO2BenV/PMA polynary nanocomposites in the potential range between -0.2 and 0.8 V, designated to three successive electron transfer processes of PMA. Finally, it was revealed that the present MWNTPVP@nano-SiO2BenV/PMA polynary composites could act as efficient heterogeneous catalysts for the electrocatalytic reduction of bromate.

  8. Polyphenol oxidase-mediated protection against oxidative stress is not associated with enhanced photosynthetic efficiency.

    Science.gov (United States)

    Boeckx, Tinne; Webster, Richard; Winters, Ana L; Webb, K Judith; Gay, Alan; Kingston-Smith, Alison H

    2015-09-01

    Polyphenol oxidases (PPOs) catalyse the oxidation of monophenols and/or o-diphenols to highly reactive o-quinones, which in turn interact with oxygen and proteins to form reactive oxygen species (ROS) and typical brown-pigmented complexes. Hence PPOs can affect local levels of oxygen and ROS. Although the currently known substrates are located in the vacuole, the enzyme is targeted to the thylakoid lumen, suggesting a role for PPOs in photosynthesis. The current study was designed to investigate the potential involvement of PPOs in the photosynthetic response to oxidative stress. Photosynthesis (A, Fv/Fm, ΦPSII, qN, qP, NPQ) was measured in leaves of a wild-type and a low-PPO mutant of red clover (Trifolium pratense 'Milvus') under control conditions and under a stress treatment designed to induce photooxidative stress: cold/high light (2 °C/580 µmol m(2 )s(-1)) or 0-10 µm methyl viologen. Foliar protein content and oxidation state were also determined. Photosynthetic performance, and chlorophyll and protein content during 4 d of cold/high light stress and 3 d of subsequent recovery under control growth conditions showed similar susceptibility to stress in both lines. However, more extensive oxidative damage to protein in mutants than wild-types was observed after treatment of attached leaves with methyl viologen. In addition, PPO activity could be associated with an increased capacity to dissipate excess energy, but only at relatively low methyl viologen doses. The presence of PPO activity in leaves did not correspond to a direct role for the enzyme in the regulation or protection of photosynthesis under cold stress. However, an indication that PPO could be involved in cellular protection against low-level oxidative stress requires further investigation. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  9. Sulfite Reductase Activity in Extracts of Various Photosynthetic Bacteria

    Science.gov (United States)

    Peck, H. D.; Tedro, S.; Kamen, M. D.

    1974-01-01

    Extracts of representative bacterial strains from the various families of photosynthetic prokaryotes are demonstrated to possess significant levels of sulfite reductase [EC 1.8.99.1; hydrogen-sulfide: (acceptor)oxidoreductase] activity with reduced methyl viologen as electron donor, but not NADPH2. The enzyme is localized primarily in the soluble fraction of the extracts, in contrast to adenylysulfate reductase [EC 1.8.99.2; AMP, sulfite: (acceptor) oxidoreductase], which is bound normally in the membrane fractions of those bacteria in which it is found. Assignment of the sulfite reductase activities to the biosynthetic (“assimilatory”) pathway is suggested by levels of specific activity noted and ready solubility. PMID:4526215

  10. [Fundamental studies in oxidation-reduction in relation to water photolysis]. Progress report, November 1, 1990--October 25, 1991

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, J.K.

    1991-12-31

    Our research has been directed at understanding three elementary processes that are central to developing membrane-based integrated chemical systems for water photolysis. These are: (1) the role of interfaces in charge separation/recombination reactions, (2) pathways for transmembrane charge separation, and (3) mechanisms of water oxidation catalyzed by transition metal coordination complexes. Historically, the chemical dynamics of each of these processes has been poorly understood, with numerous unresolved issues and conflicting viewpoints appearing in the literature. Our experimental systems comprise primarily unilamellar vesicles that have been doped with amphiphilic viologens which function as transmembrane charge relays. These systems are experimentally highly tractable and versatile, are conceptually simple, and have been widely used in a variety of organized microphase media and prototypic devices. As such, they are ideal for identifying basic principles governing reactivity.

  11. (Fundamental studies in oxidation-reduction in relation to water photolysis)

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, J.K.

    1991-01-01

    Our research has been directed at understanding three elementary processes that are central to developing membrane-based integrated chemical systems for water photolysis. These are: (1) the role of interfaces in charge separation/recombination reactions, (2) pathways for transmembrane charge separation, and (3) mechanisms of water oxidation catalyzed by transition metal coordination complexes. Historically, the chemical dynamics of each of these processes has been poorly understood, with numerous unresolved issues and conflicting viewpoints appearing in the literature. Our experimental systems comprise primarily unilamellar vesicles that have been doped with amphiphilic viologens which function as transmembrane charge relays. These systems are experimentally highly tractable and versatile, are conceptually simple, and have been widely used in a variety of organized microphase media and prototypic devices. As such, they are ideal for identifying basic principles governing reactivity.

  12. Transition metal complexes as mediator-titrants in protein redox potentiometry.

    Science.gov (United States)

    Bernhardt, Paul V; Chen, Kuan-I; Sharpe, Philip C

    2006-10-01

    A selection of nine macrocyclic Fe(III/II) and Co(III/II) transition metal complexes has been chosen to serve as a universal set of mediator-titrants in redox potentiometry of protein samples. The potential range spanned by these mediators is approximately from +300 to -700 mV vs the normal hydrogen electrode, which covers the range of most protein redox potentials accessible in aqueous solution. The complexes employed exhibit stability in both their oxidized and their reduced forms as well as pH-independent redox potentials within the range 6 < pH < 9. The mediators were also chosen on the basis of their very weak visible absorption maxima in both oxidation states, which will enable (for the first time) optical redox potentiometric titrations of proteins with relatively low extinction coefficients. This has previously been impractical with organic mediators, such as indoles, viologens and quinones, whose optical spectra interfere strongly with those of the protein.

  13. Laser flash photolysis study of photocatalytic properties of pillared interlayered clays and Fe,Al-silica mesoporous catalysts.

    Science.gov (United States)

    Glebov, Evgeni M; Pozdnyakov, Ivan P; Grivin, Vjacheslav P; Plyusnin, Victor F; Bazhin, Nikolai M; Zhang, Xu; Wu, Feng; Timofeeva, Maria N

    2013-11-01

    Laser flash photolysis was applied to determine the primary photochemical processes over iron-containing clay (montmorillonite KSF), pillared interlayered clays (PILCs) and mesoporous mesophase iron silicate materials (MMMs). For KSF, the homogeneous photochemical reaction of Fe(III) leached from the clay material resulted in the formation of OH radicals, which were monitored by means of their reaction with methyl viologen dication (MV(2+)). For PILCs and MMMs, no leaching of Fe(III) to the solution nor hydroxyl radical formation were observed. Nevertheless, these catalysts were found to exhibit a sufficient effect on phenol photoionization. The increase in quantum yields of PhO radicals is caused by the effect of PILCs and MMMs and is explained by heterogeneous processes on the surface of catalyst particles.

  14. Methanogenesis from acetate: enrichment studies.

    Science.gov (United States)

    Baresi, L; Mah, R A; Ward, D M; Kaplan, I R

    1978-01-01

    An acetate enrichment culture was initiated by inoculating anaerobic sludge from a mesophilic methane digestor into a mineral salts medium with calcium acetate as the sole carbon and energy source. This enrichment was maintained indefinitely by weekly transfer into medium of the same composition. A study of this enrichment disclosed an unexpected age-dependent inhibition of methanogenesis by H2 and formate which apparently differed from the inhibition by chloroform and benzyl viologen. This age-dependent inhibition indicated that microbial interactions of the mixed enrichment population may play a regulatory role in methane formation. Futhermore, stimulation of methanogenesis in the acetate enrichment by addition of yeast extract showed a nutrient limitation which indicated that syntrophic interactions leading to formation of growth factors may also occur. A model is presented to illustrate the possible interrelationships between methanogenic and nonmethanogenic bacteria in their growth and formation of methane and carbon dioxide from acetate. Images PMID:697356

  15. The Flavoenzyme Ferredoxin (Flavodoxin)-NADP(H) Reductase Modulates NADP(H) Homeostasis during the soxRS Response of Escherichia coli

    Science.gov (United States)

    Krapp, Adriana R.; Rodriguez, Ramiro E.; Poli, Hugo O.; Paladini, Dar|$$|Aa|fio H.; Palatnik, Javier F.; Carrillo, Néstor

    2002-01-01

    Escherichia coli cells from strain fpr, deficient in the soxRS-induced ferredoxin (flavodoxin)-NADP(H) reductase (FPR), display abnormal sensitivity to the bactericidal effects of the superoxide-generating reagent methyl viologen (MV). Neither bacteriostatic effects nor inactivation of oxidant-sensitive hydrolyases could be detected in fpr cells exposed to MV. FPR inactivation did not affect the MV-driven soxRS response, whereas FPR overexpression led to enhanced stimulation of the regulon, with concomitant oxidation of the NADPH pool. Accumulation of a site-directed FPR mutant that uses NAD(H) instead of NADP(H) had no effect on soxRS induction and failed to protect fpr cells from MV toxicity, suggesting that FPR contributes to NADP(H) homeostasis in stressed bacteria. PMID:11844783

  16. 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 (N2 ) to ammonia (NH3 ). By using methyl viologen (N,N'-dimethyl-4,4'-bipyridinium) to shuttle electrons to nitrogenase, N2 reduction to NH3 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 (H2 ) results in an enzymatic fuel cell (EFC) that is able to produce NH3 from H2 and N2 while simultaneously producing an electrical current. To demonstrate this, a charge of 60 mC was passed across H2  /N2 EFCs, which resulted in the formation of 286 nmol NH3  mg(-1) MoFe protein, corresponding to a Faradaic efficiency of 26.4 %. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. (abstract) Effects of Radiation and Oxidative Stress on Development and Morphology of Intestinal Cells

    Science.gov (United States)

    Honda, Shuji; Nelson, Gregory; Schubert, Wayne

    1993-01-01

    Intestinal cells when subjected to oxidative stress or radiation exhibit abnormal nuclear divisions observed as: 1) supernumerary cell divisions in anterior intestinal cells or 2) incomplete nuclear division and the persistence of anaphase bridges between daughter nuclei. Two oxygen sensitive mutants, mev-1 and rad-8 were observed to exhibit spontaneous supernumerary nuclear divisions at low frequency. N2 can be induced to undergo these divisions by treatment with the superoxide dismutase (SOD) inhibitor diethyl dithicarbamate or with the free radical generator methyl viologen. By contrast, the free radical generator bleomycin produces anaphase bridges in N2 intestinal nuclei at high frequency. Intestinal anaphase bridges can be induced by ionizing radiation and their formation is dependent on dose and radiation type.

  18. An artificial molecular pump

    Science.gov (United States)

    Cheng, Chuyang; McGonigal, Paul R.; Schneebeli, Severin T.; Li, Hao; Vermeulen, Nicolaas A.; Ke, Chenfeng; Stoddart, J. Fraser

    2015-06-01

    Carrier proteins consume fuel in order to pump ions or molecules across cell membranes, creating concentration gradients. Their control over diffusion pathways, effected entirely through noncovalent bonding interactions, has inspired chemists to devise artificial systems that mimic their function. Here, we report a wholly artificial compound that acts on small molecules to create a gradient in their local concentration. It does so by using redox energy and precisely organized noncovalent bonding interactions to pump positively charged rings from solution and ensnare them around an oligomethylene chain, as part of a kinetically trapped entanglement. A redox-active viologen unit at the heart of a dumbbell-shaped molecular pump plays a dual role, first attracting and then repelling the rings during redox cycling, thereby enacting a flashing energy ratchet mechanism with a minimalistic design. Our artificial molecular pump performs work repetitively for two cycles of operation and drives rings away from equilibrium toward a higher local concentration.

  19. Hydrogen storage in a potassium-ion-bound metal-organic framework incorporating crown ether struts as specific cation binding sites.

    Science.gov (United States)

    Lim, Dae-Woon; Chyun, Seung An; Suh, Myunghyun Paik

    2014-07-21

    To develop a metal-organic framework (MOF) for hydrogen storage, SNU-200 incorporating a 18-crown-6 ether moiety as a specific binding site for selected cations has been synthesized. SNU-200 binds K(+), NH4(+), and methyl viologen (MV(2+)) through single-crystal to single-crystal transformations. It exhibits characteristic gas-sorption properties depending on the bound cation. SNU-200 activated with supercritical CO2 shows a higher isosteric heat (Qst) of H2 adsorption (7.70 kJ mol(-1)) than other zinc-based MOFs. Among the cation inclusions, K(+) is the best for enhancing the isosteric heat of the H2 adsorption (9.92 kJ mol(-1)) as a result of the accessible open metal sites on the K(+) ion. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Electrocatalytic investigation of light-induced electron transfer between cytochrome c6 and photosystem I.

    Science.gov (United States)

    Proux-Delrouyre, Vanessa; Demaille, Christophe; Leibl, Winfried; Sétif, Pierre; Bottin, Hervé; Bourdillon, Christian

    2003-11-12

    A light-activated electron-transfer chain was assembled using solubilized cyanobacterial photosystem I as photoactive enzyme, cytochrome c(6) (also from cyanobacteria) as electron donor, and methyl viologen as electron acceptor. The photocatalytic activity of the ensemble was measured by direct and reversible electrochemistry of cytochrome c(6) at a surface-modified gold electrode. Analysis of the electrochemical response with an appropriate model for the reaction mechanism allowed the relation of the overall catalytic reaction rate to the individual steps of the catalytic cycle. Second-order rate constants were determined for the first time under steady-state conditions. The results validate this approach as an efficient method for the study of electron transfer between photoactive enzymes and their redox partners.

  1. Protective effects and functional mechanisms of Lactobacillus gasseri SBT2055 against oxidative stress.

    Directory of Open Access Journals (Sweden)

    Eiji Kobatake

    Full Text Available Lactobacillus gasseri SBT2055 (LG2055 is one of the probiotic lactic acid bacteria. Recently, we demonstrated that feeding with LG2055 extended the lifespan of Caenorhabditis elegans and that the prolongevity effect was dependent upon the regulation of oxidative stress response. In this study, we assessed whether LG2055 regulated the oxidative stress response of mammalian cells. In NIH-3T3 cells and primary mouse embryonic fibroblast cells, low cell proliferation rates and high reactive oxygen species levels were observed following paraquat treatment. LG2055 treatment suppressed these responses in paraquat-treated cells, indicating that LG2055 protected against oxidative stress in mammalian cells. The mRNA expression of oxidative stress-related genes, total nuclear factor-erythroid-2-related factor 2 (Nrf2 protein levels, and the nuclear translocation of Nrf2 were increased by LG2055 treatment. These results suggested that the Nrf2-antioxidant response element (ARE signaling pathway was activated by LG2055. Furthermore, c-Jun NH2-terminal kinase (JNK was activated by LG2055 treatment and the inhibition of JNK suppressed the activation of the Nrf2-ARE signaling pathway in LG2055-treated cells. Together, these findings suggest that LG2055 activated the Nrf2-ARE signaling pathway by JNK activation, thus strengthening the defense system against oxidative stress in mammalian cells.

  2. AFLP marker linked to water-stress-tolerant bulks in barley (Hordeum vulgare L.

    Directory of Open Access Journals (Sweden)

    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.

  3. 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.

  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. 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 H2O2 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 H2O2 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.

  6. Glutathione biosynthesis via activation of the nuclear factor E2-related factor 2 (Nrf2)--antioxidant-response element (ARE) pathway is essential for neuroprotective effects of sulforaphane and 6-(methylsulfinyl) hexyl isothiocyanate.

    Science.gov (United States)

    Mizuno, Keita; Kume, Toshiaki; Muto, Chie; Takada-Takatori, Yuki; Izumi, Yasuhiko; Sugimoto, Hachiro; Akaike, Akinori

    2011-01-01

    Oxidative stress plays pivotal roles in aging, neurodegenerative disease, and pathological conditions such as ischemia. We investigated the effect of sulforaphane and 6-(methysulfinyl) hexyl isothiocyanate (6-HITC), a naturally occurring isothiocyanate, on oxidative stress-induced cytotoxicity using primary neuronal cultures of rat striatum. Pretreatment with sulforaphane and 6-HITC significantly protected against H(2)O(2)- and paraquat-induced cytotoxicity in a concentration-dependent manner. Sulforaphane and 6-HITC induced the translocation of nuclear factor E2-related factor 2 (Nrf2) into the nucleus and increased the expression of γ-glutamylcysteine synthetase (γ-GCS), a rate-limiting enzyme in glutathione synthesis, and the intracellular glutathione content. Treatment with reduced glutathione (GSH) and N-acetyl-L-cysteine, a substance for glutathione synthesis, significantly prevented the cytotoxicity induced by H(2)O(2) and paraquat. Moreover, exposure to L-buthionine-sulfoximine, an irreversible inhibitor of γ-GCS, suppressed the protective effects of sulforaphane and 6-HITC. In contrast, sulforaphane and 6-HITC increased heme oxygenase-1 (HO-1) expression in neurons. However, zinc-protophorphyrin IX, a competitive inhibitor of HO-1, did not influence the protective effects of sulforaphane and 6-HITC. These results suggest that sulforaphane and 6-HITC prevent oxidative stress-induced cytotoxicity in rat striatal cultures by raising the intracellular glutathione content via an increase in γ-GCS expression induced by the activation of the Nrf2-antioxidant response element pathway.

  7. 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.

  8. Recruitment maneuver: RAMP versus CPAP pressure profile in a model of acute lung injury.

    Science.gov (United States)

    Riva, D R; Contador, R S; Baez-Garcia, C S N; Xisto, D G; Cagido, V R; Martini, S V; Morales, M M; Rocco, P R M; Faffe, D S; Zin, W A

    2009-10-31

    We examined whether recruitment maneuvers (RMs) with gradual increase in airway pressure (RAMP) provide better outcome than continuous positive airway pressure (CPAP) in paraquat-induced acute lung injury (ALI). Wistar rats received saline intraperitoneally (0.5 mL, CTRL) or paraquat (15 mg/kg, ALI). Twenty-four hours later lung mechanics [static elastance, viscoelastic component of elastance, resistive, viscoelastic and total pressures] were determined before and after recruitment with 40cmH2O CPAP for 40s or 40-s-long slow increase in pressure up to 40cmH2O (RAMP) followed by 0 or 5 cmH2O PEEP. Fractional area of alveolar collapse and PCIII mRNA were determined. All mechanical parameters and the fraction area of alveolar collapse were higher in ALI compared to CTRL. Only RAMP-PEEP maneuver significantly improved lung mechanics and decreased PCIII mRNA expression (53%) compared with ALI, while both RMs followed by PEEP decreased alveolar collapse. In conclusion, in the present experimental ALI model, RAMP followed by 5cm H2O PEEP yields a better outcome.

  9. Bioactive Peptides from Angelica sinensis Protein Hydrolyzate Delay Senescence in Caenorhabditis elegans through Antioxidant Activities

    Science.gov (United States)

    Wang, Qiangqiang; Huang, Yunxuan; Qin, Chuixin; Liang, Ming; Mao, Xinliang; Li, Shuiming; Zou, Yongdong; Jia, Weizhang; Li, Haifeng; Ma, Chung Wah; Huang, Zebo

    2016-01-01

    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. PMID:26941890

  10. One-step green synthetic approach for the preparation of multicolor emitting copper nanoclusters and their applications in chemical species sensing and bioimaging.

    Science.gov (United States)

    Bhamore, Jigna R; Jha, Sanjay; Mungara, Anil Kumar; Singhal, Rakesh Kumar; Sonkeshariya, Dhanshri; Kailasa, Suresh Kumar

    2016-06-15

    One-step green microwave synthetic approach was developed for the synthesis of copper nanoclusters (Cu NCs) and used as a fluorescent probe for the sensitive detection of thiram and paraquat in water and food samples. Unexpectedly, the prepared Cu NCs exhibited strong orange fluorescence and showed emission peak at 600 nm, respectively. Under optimized conditions, the quenching of Cu NCs emission peak at 600 nm was linearly proportional to thiram and paraquat concentrations in the ranges from 0.5 to 1000 µM, and from 0.2 to 1000 µM, with detection limits of 70 nM and 49 nM, respectively. In addition, bioimaging studies against Bacillus subtilis through confocal fluorescence microscopy indicated that Cu NCs showed strong blue and green fluorescence signals, good permeability and minimum toxicity against the various bacteria species, which demonstrates their potential feasibility for chemical species sensing and bioimaging applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Alternative herbicides to manage Italian ryegrass (Lolium multiflorum lam) resistant to glyphosate at different phenological stages.

    Science.gov (United States)

    Christoffoleti, Pedro Jacob; Trentin, Renato; Tocchetto, Saulo; Marochi, Aroldo; Galli, Antonio João Batista; López-Ovejero, Ramiro Fernando; Nicolai, Marcelo

    2005-01-01

    During the growing season of 2002--2003, field and greenhouse experiments were conducted with the objective of evaluating the influence of Italian ryegrass phenological stages and management alternatives on the control of resistant biotypes to glyphosate. Three field experiments were conducted in Lagoa Vermelha, RS, Brazil and glyphosate was applied alone and in combinations with alternative herbicides. Two greenhouse experiments were also conducted at the Department of Crop Science, ESALQ/USP, Piracicaba, SP, Brazil. The Italian ryegrass resistant population was collected from Lagoa Vermelha, RS, Brazil. From the results it was possible to conclude that: (i) the more advanced the phenological stage of application, the more difficult the control of resistant Italian ryegrass by glyphosate, mainly by the rate of 960 g a.i. ha(-1); however, this rate applied at earlier phenological stage (five tillers), the control was higher than 90%; (ii) with the increment of glyphosate rate, it significant response was observed on the control at all stages of application; (iii) the mixture of glyphosate + clethodim (1440 + 72 g a.i. ha(-1)), paraquat + diuron (500 + 250 g a.i. ha(-1)), at all stages of application and clethodim (96 g a.i. ha(-1)) and paraquat + diuron (300 + 150 g a.i. ha(-1)) at the initial stages until pre-flowering were excellent alternatives for management of these populations; and (iv) the response of control was much faster for the mixture of glyphosate + clethodim, independently of growth stage.

  12. Biogenesis of Fe/S proteins and pathogenicity: IscR plays a key role in allowing Erwinia chrysanthemi to adapt to hostile conditions.

    Science.gov (United States)

    Rincon-Enriquez, Gabriel; Crété, Patrice; Barras, Frédéric; Py, Béatrice

    2008-03-01

    The Erwinia chrysanthemi genome is predicted to encode three systems, Nif, Isc and Suf, known to assist Fe/S cluster biogenesis and the CsdAE cysteine desulphurase. Single iscU, hscA and fdx mutants were found sensitive to paraquat and exhibited reduced virulence on both chicory leaves and Arabidopsis thaliana. Depletion of the whole Isc system led to a pleiotropic phenotype, including sensitivity to both paraquat and 2,2'-dipyridyl, auxotrophies for branched-chain amino acids, thiamine, nicotinic acid, and drastic alteration in virulence. IscR was able to suppress all of the phenotypes listed above in a sufC-dependent manner while depletion of the Isc system led to IscR-dependent activation of the suf operon. No virulence defects were found associated with csdA or nifS mutations. Surprisingly, we found that the sufC mutant was virulent against A. thaliana, whereas its virulence had been found altered in Saintpaulia. Collectively, these results lead us to propose that E. chrysanthemi possess the Fe/S biogenesis strategy suited to the physico-chemical conditions encountered in its host upon infection. In this view, the IscR regulator, which controls both Isc and Suf, is predicted to play a major role in the ability of E. chrysanthemi to colonize a wide array of different plants.

  13. Protective effects and functional mechanisms of Lactobacillus gasseri SBT2055 against oxidative stress.

    Science.gov (United States)

    Kobatake, Eiji; Nakagawa, Hisako; Seki, Takahiro; Miyazaki, Tadaaki

    2017-01-01

    Lactobacillus gasseri SBT2055 (LG2055) is one of the probiotic lactic acid bacteria. Recently, we demonstrated that feeding with LG2055 extended the lifespan of Caenorhabditis elegans and that the prolongevity effect was dependent upon the regulation of oxidative stress response. In this study, we assessed whether LG2055 regulated the oxidative stress response of mammalian cells. In NIH-3T3 cells and primary mouse embryonic fibroblast cells, low cell proliferation rates and high reactive oxygen species levels were observed following paraquat treatment. LG2055 treatment suppressed these responses in paraquat-treated cells, indicating that LG2055 protected against oxidative stress in mammalian cells. The mRNA expression of oxidative stress-related genes, total nuclear factor-erythroid-2-related factor 2 (Nrf2) protein levels, and the nuclear translocation of Nrf2 were increased by LG2055 treatment. These results suggested that the Nrf2-antioxidant response element (ARE) signaling pathway was activated by LG2055. Furthermore, c-Jun NH2-terminal kinase (JNK) was activated by LG2055 treatment and the inhibition of JNK suppressed the activation of the Nrf2-ARE signaling pathway in LG2055-treated cells. Together, these findings suggest that LG2055 activated the Nrf2-ARE signaling pathway by JNK activation, thus strengthening the defense system against oxidative stress in mammalian cells.

  14. Conserved and divergent functions of RcrRPQ in Streptococcus gordonii and S. mutans.

    Science.gov (United States)

    Shields, Robert C; Burne, Robert A

    2015-08-01

    In the dental caries pathogen Streptococcus mutans, an MarR-like transcriptional regulator (RcrR), two ABC efflux pumps (RcrPQ) and two effector peptides encoded in the rcrRPQ operon provide molecular connections between stress tolerance, (p)ppGpp metabolism and genetic competence. Here, we examined the role of RcrRPQ in the oral commensal S. gordonii. Unlike in S. mutans, introduction of polar or non-polar rcrR mutations into S. gordonii elicited no significant changes in transformation efficiency. However, S. gordonii rcrR mutants were markedly impaired in their ability to grow in the presence of hydrogen peroxide, paraquat, low pH or elevated temperature. Sensitivity to paraquat could also be conferred by mutation of cysteine residues that are present in the RcrR protein of S. gordonii, but not in S. mutans RcrR. Thus, stress tolerance is a conserved function of RcrRPQ in a commensal and pathogenic streptococcus, but the study reveals additional differences in regulation of genetic competence development between S. mutans and S. gordonii. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  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. 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

  17. Why Amphibians Are More Sensitive than Mammals to Xenobiotics

    Science.gov (United States)

    Quaranta, Angelo; Bellantuono, Vito; Cassano, Giuseppe; Lippe, Claudio

    2009-01-01

    Dramatic declines in amphibian populations have been described all over the world since the 1980s. The evidence that the sensitivity to environmental threats is greater in amphibians than in mammals has been generally linked to the observation that amphibians are characterized by a rather permeable skin. Nevertheless, a numerical comparison of data of percutaneous (through the skin) passage between amphibians and mammals is lacking. Therefore, in this investigation we have measured the percutaneous passage of two test molecules (mannitol and antipyrine) and three heavily used herbicides (atrazine, paraquat and glyphosate) in the skin of the frog Rana esculenta (amphibians) and of the pig ear (mammals), by using the same experimental protocol and a simple apparatus which minimizes the edge effect, occurring when the tissue is clamped in the usually used experimental device. The percutaneous passage (P) of each substance is much greater in frog than in pig. LogP is linearly related to logKow (logarithm of the octanol-water partition coefficient). The measured P value of atrazine was about 134 times larger than that of glyphosate in frog skin, but only 12 times in pig ear skin. The FoD value (Pfrog/Ppig) was 302 for atrazine, 120 for antipyrine, 66 for mannitol, 29 for paraquat, and 26 for glyphosate. The differences in structure and composition of the skin between amphibians and mammals are discussed. PMID:19888346

  18. Toxicity of herbicides used in the sugarcane crop to diazotrophic bacterium Herbaspirillum seropedicae

    Directory of Open Access Journals (Sweden)

    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. 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.

  20. 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.

  1. Sterols from Mytilidae show anti-aging and neuroprotective effects via anti-oxidative activity.

    Science.gov (United States)

    Sun, Yujuan; Lin, Yanfei; Cao, Xueli; Xiang, Lan; Qi, Jianhua

    2014-11-25

    For screening anti-aging samples from marine natural products, K6001 yeast strain was employed as a bioassay system. The active mussel extract was separated to give an active sterol fraction (SF). SF was further purified, and four sterol compounds were obtained. Their structures were determined to be cholesterol (CHOL), brassicasterol, crinosterol, and 24-methylenecholesterol. All compounds showed similar anti-aging activity. To understand the action mechanism involved, anti-oxidative experiments, reactive oxygen species (ROS) assays, and malondialdehyde (MDA) tests were performed on the most abundant compound, CHOL. Results indicated that treatment with CHOL increases the survival rate of yeast under oxidative stress and decreases ROS and MDA levels. In addition, mutations of uth1, skn7, sod1, and sod2, which feature a K6001 background, were employed and the lifespans of the mutations were not affected by CHOL. These results demonstrate that CHOL exerts anti-aging effects via anti-oxidative stress. Based on the connection between neuroprotection and anti-aging, neuroprotective experiments were performed in PC12 cells. Paraquat was used to induce oxidative stress and the results showed that the CHOL and SF protect the PC12 cells from the injury induced by paraquat. In addition, these substance exhibited nerve growth factor (NGF) mimic activities again confirmed their neuroprotective function.

  2. 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.

  3. FIBRILLIN4 Is Required for Plastoglobule Development and Stress Resistance in Apple and Arabidopsis1[W][OA

    Science.gov (United States)

    Singh, Dharmendra K.; Maximova, Siela N.; Jensen, Philip J.; Lehman, Brian L.; Ngugi, Henry K.; McNellis, Timothy W.

    2010-01-01

    The fibrillins are a large family of chloroplast proteins that have been linked with stress tolerance and disease resistance. FIBRILLIN4 (FIB4) is found associated with the photosystem II light-harvesting complex, thylakoids, and plastoglobules, which are chloroplast compartments rich in lipophilic antioxidants. For this study, FIB4 expression was knocked down in apple (Malus 3 domestica) using RNA interference. Plastoglobule osmiophilicity was decreased in fib4 knockdown (fib4 KD) tree chloroplasts compared with the wild type, while total plastoglobule number was unchanged. Compared with the wild type, net photosynthetic CO2 fixation in fib4 KD trees was decreased at high light intensity but was increased at low light intensity. Furthermore, fib4 KD trees produced more anthocyanins than the wild type when transferred from low to high light intensity, indicating greater sensitivity to high light stress. Relative to the wild type, fib4 KD apples were more sensitive to methyl viologen and had higher superoxide levels during methyl viologen treatment. Arabidopsis (Arabidopsis thaliana) fib4 mutants and fib4 KD apples were more susceptible than their wild-type counterparts to the bacterial pathogens Pseudomonas syringae pathovar tomato and Erwinia amylovora, respectively, and were more sensitive to ozone-induced tissue damage. Following ozone stress, plastoglobule osmiophilicity decreased in wild-type apple and remained low in fib4 KD trees; total plastoglobule number increased in fib4 KD apples but not in the wild type. These results indicate that FIB4 is required for plastoglobule development and resistance to multiple stresses. This study suggests that FIB4 is involved in regulating plastoglobule content and that defective regulation of plastoglobule content leads to broad stress sensitivity and altered photosynthetic activity. PMID:20813909

  4. 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.

  5. Hollow mesoporous raspberry-like colloids with removable caps as photoresponsive nanocontainers

    Science.gov (United States)

    Hu, Chi; West, Kevin R.; Scherman, Oren A.

    2016-04-01

    The fabrication, characterisation and controlled cargo release of hollow mesoporous raspberry-like colloids (HMRCs), which are assembled by utilising host-guest complexation of cucurbit[8]uril (CB[8]) are described. CB[8] is employed as a supramolecular linker to `stick' the viologen functionalised paramagnetic iron oxide nanoparticles onto an azobenzene functionalised hollow mesoporous silica core. The formed HMRCs are photoresponsive and can be reversibly disassembled upon light irradiation, endowing them with an ability to release loaded cargo under photocontrol. While the assembled HMRCs retain cargo inside their cavity, disassembled particles with their iron oxide nanoparticle `caps' removed will release the loaded cargo through the mesoporous shell of the hollow silica colloids. A model system using a boronic acid derivative as the cargo in the HMRCs and Alizarin Red salt as a sensor for the released boronic acid is demonstrated.The fabrication, characterisation and controlled cargo release of hollow mesoporous raspberry-like colloids (HMRCs), which are assembled by utilising host-guest complexation of cucurbit[8]uril (CB[8]) are described. CB[8] is employed as a supramolecular linker to `stick' the viologen functionalised paramagnetic iron oxide nanoparticles onto an azobenzene functionalised hollow mesoporous silica core. The formed HMRCs are photoresponsive and can be reversibly disassembled upon light irradiation, endowing them with an ability to release loaded cargo under photocontrol. While the assembled HMRCs retain cargo inside their cavity, disassembled particles with their iron oxide nanoparticle `caps' removed will release the loaded cargo through the mesoporous shell of the hollow silica colloids. A model system using a boronic acid derivative as the cargo in the HMRCs and Alizarin Red salt as a sensor for the released boronic acid is demonstrated. Electronic supplementary information (ESI) available. See DOI: 10.1039/C6NR01016D

  6. The Roles of Molecular Structure and Effective Optical Symmetry in Evolving Dipolar Chromophoric Building Blocks to Potent Octopolar NLO Chromophores

    Science.gov (United States)

    Ishizuka, Tomoya; Sinks, Louise E.; Song, Kai; Hung, Sheng-Ting; Nayak, Animesh; Clays, Koen; Therien, Michael J.

    2011-01-01

    A series of mono-, bis-, tris-, and tetrakis-(porphinato)zinc(II) (PZn)-elaborated ruthenium(II) bis(terpyridine) (Ru) complexes has been synthesized in which an ethyne unit connects the macrocycle meso carbon atom to terpyridyl (tpy) 4-, 4′-, and 4″- positions. These supermolecular chromophores, based on the ruthenium(II) [5-(4′-ethynyl-(2,2′;6′,2″-terpyridinyl))-10,20-bis(2′,6′-bis(3,3-dimethyl-1-butyloxy)phenyl)porphinato]zinc(II)-(2,2′;6′,2″-terpyridine)2+ bis-hexafluorophosphate (RuPZn) archetype, evince strong mixing of the PZn-based oscillator strength with ruthenium terpyridyl charge resonance bands. Potentiometric and linear absorption spectroscopic data indicate that for structures in which multiple PZn moieties are linked via ethynes to a [Ru(tpy)2]2+ core, little electronic coupling is manifest between PZn units, regardless of whether they are located on the same or opposite tpy ligand. Congruent with these experiments, pump-probe transient absorption studies suggest that the individual RuPZn fragments of these structures exhibit, at best, only modest excited-state electronic interactions that derive from factors other than the dipole-dipole interactions of these strong oscillators; this approximate independent character of the component RuPZn oscillators enables fabrication of NLO multipoles with extraordinary hyperpolarizabilities. Dynamic hyperpolarizability (βλ) values and depolarization ratios (ρ) were determined from hyper-Rayleigh light scattering (HRS) measurements carried out at an incident irradiation wavelength (λinc) of 1300 nm. The depolarization ratio data provide an experimental measure of chromophore optical symmetry; appropriate coupling of multiple charge-transfer oscillators produces structures having enormous averaged hyperpolarizabilities (βHRS values), while evolving the effective chromophore symmetry from purely dipolar (e.g., Ru(tpy)[4-(Znporphyrin)ethynyl-tpy](PF6)2, βHRS = 1280 × 10−30 esu, ρ = 3

  7. Synergistic stress exacerbation in hippocampal neurons: Evidence favoring the dual-hit hypothesis of neurodegeneration.

    Science.gov (United States)

    Heinemann, Scott D; Posimo, Jessica M; Mason, Daniel M; Hutchison, Daniel F; Leak, Rehana K

    2016-08-01

    The dual-hit hypothesis of neurodegeneration states that severe stress sensitizes vulnerable cells to subsequent challenges so that the two hits are synergistic in their toxic effects. Although the hippocampus is vulnerable to a number of neurodegenerative disorders, there are no models of synergistic cell death in hippocampal neurons in response to combined proteotoxic and oxidative stressors, the two major characteristics of these diseases. Therefore, a relatively high-throughput dual-hit model of stress synergy was developed in primary hippocampal neurons. In order to increase the rigor of the study and strengthen the interpretations, three independent, unbiased viability assays were employed at multiple timepoints. Stress synergy was elicited when hippocampal neurons were treated with the proteasome inhibitor MG132 followed by exposure to the oxidative toxicant paraquat, but only after 48 h. MG132 and paraquat only elicited additive effects 24 h after the final hit and even loss of heat shock protein 70 activity and glutathione did not promote stress synergy at this early timepoint. Dual hits of MG132 elicited modest glutathione loss and slightly synergistic toxic effects 48 h after the second hit, but only at some concentrations and only according to two viability assays (metabolic fitness and cytoskeletal integrity). The thiol N-acetyl cysteine protected hippocampal neurons against dual MG132/MG132 hits but not dual MG132/paraquat hits. These findings support the view that proteotoxic and oxidative stress propel and propagate each other in hippocampal neurons, leading to synergistically toxic effects, but not as the default response and only after a delay. The neuronal stress synergy observed here lies in contrast to astrocytic responses to dual hits, because astrocytes that survive severe proteotoxic stress resist additional cell loss following second hits. In conclusion, a new model of hippocampal vulnerability was developed for the testing of therapies

  8. 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 (H2O2), which can yield hydroxyl radical. Paraquat suppressed peptide-mediated induction of comX in a progressive and cumulative fashion, whereas the response to H2O2 displayed a strong threshold behavior. Low concentrations of H2O2 had little effect on induction of comX or the bacteriocin gene cipB, but expression of these genes declined sharply if extracellular H2O2 exceeded a threshold concentration. These effects were not due to decreased reporter gene fluorescence. Two different threshold concentrations were observed in the response to H2O2, depending on the gene promoter that was analyzed and the pathway by which the competence regulon was stimulated. The results show that paraquat and H2O2 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.IMPORTANCEStreptococcus 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-to-cell heterogeneity. Although oxidative

  9. 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

    in other studies on microsomal modulation of the cytotoxicity of the test substances. Moderate to good correlations were found between the cytotoxicity data and rodent lethality data, and the addition of microsomes slightly improved the in vitro/in vivo concordance. The evidence to support the relevance......The cytotoxicity of MEIC chemicals Nos, 11-30 was evaluated by determination of neutral red uptake in Balb/c 3T3 mouse fibroblasts with and without the addition of a microsomal activation mixture. The use of microsomes significantly decreased the cytotoxicity of malathion, 2,4-dichlorophenoxyacetic...... 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...

  10. Oxidative stress and Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    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.

  11. 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.

  12. Phenotypic effects of membrane protein overexpression in Saccharomyces cerevisiae

    Science.gov (United States)

    Melén, Karin; Blomberg, Anders; von Heijne, Gunnar

    2006-07-01

    Large-scale protein overexpression phenotype screens provide an important complement to the more common gene knockout screens. Here, we have targeted the so far poorly understood Saccharomyces cerevisiae membrane proteome and report growth phenotypes for a strain collection overexpressing 600 C-terminally tagged integral membrane proteins grown both under normal and three different stress conditions. Although overexpression of most membrane proteins reduce the growth rate in synthetic defined medium, we identify a large number of proteins that, when overexpressed, confer specific resistance to various stress conditions. Our data suggest that regulation of glycosylphosphatidylinositol anchor biosynthesis and the Na+/K+ homeostasis system constitute major downstream targets of the yeast PKA/RAS pathway and point to a possible connection between the early secretory pathway and the cells' response to oxidative stress. We also have quantified the expression levels for >550 membrane proteins, facilitating the choice of well expressing proteins for future functional and structural studies. caffeine | paraquat | salt tolerance | yeast

  13. 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

    Directory of Open Access Journals (Sweden)

    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

  14. 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

  15. Studies on preparation and characterization of Fe/TiO2 catalyst in photocatalysis applications

    Science.gov (United States)

    Kruanetr, Senee; Wanchanthuek, Ratchaneekorn

    2017-07-01

    A Fe/TiO2 photocatalyst was synthesized and used as the catalyst in paraquat degradation as a test reaction to examine the photo-properties. The TEM, XRD, FTIR, UV-vis diffuse reflectance spectrometer, XPS and BET surface area analysis methods were used as the characterization techniques to investigate the physical and chemical properties of the prepared catalyst. Moreover, some of the preparation parameters, such as the preparation method, the content of Fe loading, thermal treatment and source of light irradiation, were also examined. According to the characterization and the expressed catalytic activity, it was found that the factor that significantly responded to the catalyst activity was the -OH surface species on the catalyst surface. Moreover, the lower band gap energy of the Fe/TiO2 catalyst was also an important parameter that gave high catalytic properties because of the higher light adsorption. The preparation scheme and the photodegradation mechanism were proposed.

  16. Toxicogenetics: In Search of Host Susceptibility to Environmental Toxicants

    Directory of Open Access Journals (Sweden)

    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.

  17. The role of lager beer yeast in oxidative stability of model beer

    DEFF Research Database (Denmark)

    Berner, Torben Sune; Arneborg, Nils

    2012-01-01

    ageing experiments. Interestingly, the strain with the lowest oxidative stress resistance and lowest secretion of thioredoxin, as measured by Western blotting, resulted in the highest uptake of iron, as measured by inductively coupled plasma-mass spectrometry, and the slowest formation of radicals......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...... 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...

  18. Fucoxanthin increases lifespan of Drosophila melanogaster and Caenorhabditis elegans.

    Science.gov (United States)

    Lashmanova, Ekaterina; Proshkina, Ekaterina; Zhikrivetskaya, Svetlana; Shevchenko, Oksana; Marusich, Elena; Leonov, Sergey; Melerzanov, Alex; Zhavoronkov, Alex; Moskalev, Alexey

    2015-10-01

    The pharmacological activation of stress-defense mechanisms is one of the perspective ways to increase human lifespan. The goal of the present study was to study the effects on lifespan of Drosophila melanogaster and Caenorhabditis elegans of two carotenoids: ß-carotene and fucoxanthin, which are bioactive natural substances in human diet. In addition, the effects of carotenoids on the flies survival were studied under stress conditions, including starvation, thermal stress (35°C), oxidative stress (20 mM paraquat), as well as locomotor activity, fecundity, and genes expression level. Our results demonstrated lifespan extension of flies by both carotenoids. However, the positive effects on the lifespan of C. elegans were revealed only for fucoxanthin. In presence of carotenoids decreased flies' fecundity, increased spontaneous locomotor activity and resistance to oxidative stress were detected. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. Efeito da época de semeadura de Brachiaria decumbens e de dessecantes em pré-colheita sobre o rendimento de grãos do feijoeiro e a biomassa forrageira em cultivo consorciado Effect of sowing dates of Brachiaria decumbens and desiccant in pre-harvest on the yield of grain bean and forage biomass in intercropped system

    Directory of Open Access Journals (Sweden)

    Abner José de Carvalho

    2011-10-01

    Full Text Available Com o objetivo de avaliar a época de semeadura e os efeitos da dessecação da Brachiaria decumbens em consórcio com duas cultivares de feijão (Phaseolus vulgaris L., foi conduzido um experimento, em Coimbra, MG, em esquema fatorial envolvendo cultivares de feijão (Ouro Vermelho e VC3, duas épocas de semeadura da braquiária (simultânea e na capina do feijão, três tipos de dessecação (sem dessecação, Carfentrazone-ethil e Paraquat, mais dois tratamentos adicionais: os monocultivos do feijão e da braquiária, em DBC com quatro repetições. O feijoeiro foi plantado com semeadora mecanizada, no espaçamento de 0,50 m entre linhas. A braquiária foi semeada com semeadora manual, sempre nas entrelinhas do feijoeiro. Foram avaliados o estande final de plantas e o rendimento de grãos do feijão e a biomassa seca da parte aérea da braquiária, aos 15 e aos 60 dias após a colheita do feijão. Concluiu-se que a cultivar Ouro Vermelho é mais indicada para o consórcio com B. decumbens na safra das águas que a VC3. O retardamento da semeadura da braquiária proporciona maior rendimento de grãos do feijão, mas prejudica a produção de biomassa seca da forrageira. A dessecação na pré-colheita não influencia a produtividade do feijoeiro, mas, quando é realizada com paraquat, prejudica a produção de biomassa seca da forrageira.In order to evaluate different sowing dates and the effect of desiccation on Brachiaria decumbens intercropped with two beans cultivars (Phaseolus vulgaris L., an experiment was conducted in Coimbra, MG in a factorial design involving two bean cultivars (Ouro Vermelho and VC3, two sowing dates (simultaneous and during bean weeding, three desiccation types (without desiccation, Carfentrazone-ethyl and Paraquat, plus two additional plantings of monoculture bean and brachiaria in DBC with four replications. The beans were seeded by mechanized planting with 0.50 m spacing between the rows. Brachiaria was sown by

  20. Tall oil precursors and turpentine in black and white spruce

    Energy Technology Data Exchange (ETDEWEB)

    Conner, A.H.; Diehl, M.A.; Rowe, J.W.

    1980-01-01

    The heartwood of Picea mariana contained resin acids (1) 14, fatty acids (11) 2, esters 10, nonsaponifiables 13, and phenolic compounds 61%, whereas P. glauca contained (1) 12, (11) 1, esters 42, nonsaponifiables 13, and phenolic compounds 32%. The (1) consisted primarily of palustric, isopimaric, abietic,and dehydroabietic acids, and fatty acids were mainly oleic, linoleic, and 5,9,12-octadecatrienoic acids. Turpentine obtained from these species was primarily a mixture of alpha- and beta-pinene. Paraquat (111) treatment induced up to a 7-fold increase in the content of oleoresin of these species, but visual indications of lightwood were not observed. The components of turpentine and Et/sub 2/0 extractives after (111) treatment were similar to those before treatment.

  1. Mitochondria poised at a fission-fusion balance?: A quantitative assessment of mitochondrial network complexity

    CERN Document Server

    Zamponi, Nahuel; Billoni, Orlando V; Cannas, Sergio A; Helguera, Pablo R; Chialvo, Dante R

    2016-01-01

    Mitochondrial networks have been shown to exhibit a variety of complex behaviors, including cell-wide oscillations of mitochondrial energy states, as well as a phase transition in response to oxidative stress. Since functional status and structural properties are often intertwined, in this work we look at the structural properties of the organelle in normal mouse embryonic fibroblasts, describing its most relevant features. Subsequently we manipulated mitochondrial morphology using two interventions with opposite effects: over-expression of mitofusin 1, a protein that promotes mitochondria fusion, and paraquat treatment, a compound that induces mitochondrial fragmentation due to oxidative stress. Quantitative analysis of the organelle's structural clusters revealed that healthy mitochondrial networks were in a status intermediate between the extremes of highly fragmented and completely fusioned networks. This was confirmed by a comparison of our empirical findings with those of a recently described computatio...

  2. A novel ion pairing LC/MS metabolomics protocol for study of a variety of biologically relevant polar metabolites.

    Science.gov (United States)

    Knee, Jose M; Rzezniczak, Teresa Z; Barsch, Aiko; Guo, Kevin Z; Merritt, Thomas J S

    2013-10-01

    We report a method of ion-pairing liquid chromatography coupled to mass spectrometry (IP-LC-MS) that we have developed for the sensitive detection and quantification of a variety of biologically relevant polar molecules. We use the ion-pairing agent diamyl ammonium to improve chromatographic resolution of polar compounds, such as nucleotide cofactors, sugar phosphates, and organic acids, that are generally poorly retained by conventional reverse phase chromatographic methods. This method showed good linearity (average R value of 0.996) and reproducibility (generally RSD values metabolomic signature of three distinct biological systems: the metabolic response to lack of superoxide dismutase activity and to paraquat induced oxidative stress, and the metabolic profiles of four different Drosophila species. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. 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

  4. 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)

  5. Clinical and forensic signs related to chemical burns: a mechanistic approach.

    Science.gov (United States)

    Dinis-Oliveira, Ricardo Jorge; Carvalho, Félix; Moreira, Roxana; Proença, Jorge Brandão; Santos, Agostinho; Duarte, José Alberto; Bastos, Maria de Lourdes; Magalhães, Teresa

    2015-06-01

    This manuscript highlights and critically analyses clinical and forensic signs related to chemical burns. Signs that may lead to suspicion of a particular chemical are thoroughly discussed regarding its underlying mechanisms. Burns due to sulfuric, hydrofluoric, nitric, hydrochloric (muriatic) and acetic (including derivatives) acids, hydrogen sulphide, sodium (caustic soda) and calcium (cement) hydroxides, paraquat, burns after inflation and rupture of airbags, povidone-iodine, chlorhexidine/alcohol (in preterm infants), laxatives, and vesicants (warfare agents), will be reviewed since these are the most common agents found in daily practice, for which relevant and timed information may be helpful in formulating an emergency treatment protocols and toxicological analysis. Copyright © 2014 Elsevier Ltd and ISBI. All rights reserved.

  6. Oxidative stress contributes to outcome severity in a Drosophila melanogaster model of classic galactosemia.

    Science.gov (United States)

    Jumbo-Lucioni, Patricia P; Hopson, Marquise L; Hang, Darwin; Liang, Yongliang; Jones, Dean P; Fridovich-Keil, Judith L

    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

  7. Integration of the free liquid membrane into electrokinetic supercharging - capillary electrophoresis for the determination of cationic herbicides in environmental water samples.

    Science.gov (United States)

    Chui, Mei Qi; Thang, Lee Yien; See, Hong Heng

    2017-01-20

    A new approach based on the integration of the free liquid membrane (FLM) into electrokinetic supercharging (EKS) was demonstrated to be a new powerful tool used in order to enhance online preconcentration efficiency in capillary electrophoresis (CE). A small plug of water immiscible organic solvent was used as a membrane interface during the electrokinetic sample injection step in EKS in order to significantly enhance the analyte stacking efficiency. The new online preconcentration strategy was evaluated for the determination of paraquat and diquat present in the environmental water samples. The optimised FLM-EKS conditions employed were as follows: hydrodynamic injection (HI) of 20mM potassium chloride as leading electrolyte at 50mbar for 75s (3% of the total capillary volume) followed by the HI of tris(2-ethylhexyl) phosphate (TEHP) as FLM at a 1mm length (0.1% of the capillary volume). The sample was injected at 10kV for 360s, followed by the HI of 20mM cetyl trimethylammonium bromide (CTAB) as terminating electrolyte at 50mbar for 50s (2% of the total capillary volume). The separation was performed in 12mM ammonium acetate and 30mM NaCl containing 20% MeOH at +25kV with UV detection at 205nm. Under optimised conditions, the sensitivity was enhanced between 1500- and 1866-fold when compared with the typical HI at 50mbar for 50s. The detection limit of the method for paraquat and diquat was 0.15-0.20ng/mL, with RSDs below 5.5%. Relative recoveries in spiked river water were in the range of 95.4-97.5%. A comparison was also made between the proposed approach with sole preconcentration of the field-enhanced sample injection (FASI) and EKS in the absence of the FLM. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. A Au nanoparticle-incorporated sponge as a versatile transmission surface-enhanced Raman scattering substrate.

    Science.gov (United States)

    Shin, Kayeong; Chung, Hoeil

    2015-08-07

    We report a sponge-based transmission surface-enhanced Raman scattering (TSERS) substrate that combines the bulk sampling capabilities of a transmission measurement to improve the quantitative representation of sample concentration with several sponge properties useful for analysis such as fast sample uptake, easy sample enrichment, and a stable polymeric structure. Among nine commercially available sponges made of different materials, a melamine sponge was ultimately selected for this study because it provided the fastest sample uptake and a low background Raman signal. Simultaneously, the amino groups and three-nitrogen hybrid rings in its structure could easily hold Au nanoparticles (AuNPs) inside the sponge. AuNP-incorporated sponges (AuNP sponges) were prepared by simply soaking a melamine sponge in a AuNP solution; these sponges were initially used to measure 4-nitrobenzenethiol (4-NBT) samples with different concentrations in order to evaluate their ability as TSERS substrates. The intensities of the 4-NBT peaks clearly varied according to changes in the concentration, and the relative standard deviation (RSD) of the peak intensity estimated by the measurements of five independently prepared AuNP sponges was 10.0%. Sample enrichment was easily completed by repeated suctioning of the sample into the AuNP sponges followed by depletion of the solvent, so three-time enrichment doubled the intensity. Furthermore, paraquat samples were prepared in diverse matrices (de-ionized water, tap water, river water, and orange juice) and measured using the AuNP sponges. The paraquat peaks were clearly observed from these samples and their peak intensities became smaller with the increased compositional complexity of the matrices. Our overall results demonstrate that the TSERS sponge substrates are easy to prepare and practically versatile for SERS analysis of diverse samples.

  9. Honey bee (Apis mellifera) drones survive oxidative stress due to increased tolerance instead of avoidance or repair of oxidative damage.

    Science.gov (United States)

    Li-Byarlay, Hongmei; Huang, Ming Hua; Simone-Finstrom, Michael; Strand, Micheline K; Tarpy, David R; Rueppell, Olav

    2016-10-01

    Oxidative stress can lead to premature aging symptoms and cause acute mortality at higher doses in a range of organisms. Oxidative stress resistance and longevity are mechanistically and phenotypically linked; considerable variation in oxidative stress resistance exists among and within species and typically covaries with life expectancy. However, it is unclear whether stress-resistant, long-lived individuals avoid, repair, or tolerate molecular damage to survive longer than others. The honey bee (Apis mellifera L.) is an emerging model system that is well-suited to address this question. Furthermore, this species is the most economically important pollinator, whose health may be compromised by pesticide exposure, including oxidative stressors. Here, we develop a protocol for inducing oxidative stress in honey bee males (drones) via Paraquat injection. After injection, individuals from different colony sources were kept in common social conditions to monitor their survival compared to saline-injected controls. Oxidative stress was measured in susceptible and resistant individuals. Paraquat drastically reduced survival but individuals varied in their resistance to treatment within and among colony sources. Longer-lived individuals exhibited higher levels of lipid peroxidation than individuals dying early. In contrast, the level of protein carbonylation was not significantly different between the two groups. This first study of oxidative stress in male honey bees suggests that survival of an acute oxidative stressor is due to tolerance, not prevention or repair, of oxidative damage to lipids. It also demonstrates colony differences in oxidative stress resistance that might be useful for breeding stress-resistant honey bees. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. The TrkAIII oncoprotein inhibits mitochondrial free radical ROS-induced death of SH-SY5Y neuroblastoma cells by augmenting SOD2 expression and activity at the mitochondria, within the context of a tumour stem cell-like phenotype.

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    Pierdomenico Ruggeri

    Full Text Available The developmental and stress-regulated alternative TrkAIII splice variant of the NGF receptor TrkA is expressed by advanced stage human neuroblastomas (NBs, correlates with worse outcome in high TrkA expressing unfavourable tumours and exhibits oncogenic activity in NB models. In the present study, we report that constitutive TrkAIII expression in human SH-SY5Y NB cells inhibits Rotenone, Paraquat and LY83583-induced mitochondrial free radical reactive oxygen species (ROS-mediated death by stimulating SOD2 expression, increasing mitochondrial SOD2 activity and attenuating mitochondrial free radical ROS production, in association with increased mitochondrial capacity to produce H2O2, within the context of a more tumour stem cell-like phenotype. This effect can be reversed by the specific TrkA tyrosine kinase inhibitor GW441756, by the multi-kinase TrkA inhibitors K252a, CEP-701 and Gö6976, which inhibit SOD2 expression, and by siRNA knockdown of SOD2 expression, which restores the sensitivity of TrkAIII expressing SH-SY5Y cells to Rotenone, Paraquat and LY83583-induced mitochondrial free radical ROS production and ROS-mediated death. The data implicate the novel TrkAIII/SOD2 axis in promoting NB resistance to mitochondrial free radical-mediated death and staminality, and suggest that the combined use of TrkAIII and/or SOD2 inhibitors together with agents that induce mitochondrial free radical ROS-mediated death could provide a therapeutic advantage that may also target the stem cell niche in high TrkA expressing unfavourable NB.

  11. The TrkAIII Oncoprotein Inhibits Mitochondrial Free Radical ROS-Induced Death of SH-SY5Y Neuroblastoma Cells by Augmenting SOD2 Expression and Activity at the Mitochondria, within the Context of a Tumour Stem Cell-like Phenotype

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    Di Ianni, Natalia; Cappabianca, Lucia; Ragone, Marzia; Ianni, Giulia; Gulino, Alberto; Mackay, Andrew R.

    2014-01-01

    The developmental and stress-regulated alternative TrkAIII splice variant of the NGF receptor TrkA is expressed by advanced stage human neuroblastomas (NBs), correlates with worse outcome in high TrkA expressing unfavourable tumours and exhibits oncogenic activity in NB models. In the present study, we report that constitutive TrkAIII expression in human SH-SY5Y NB cells inhibits Rotenone, Paraquat and LY83583-induced mitochondrial free radical reactive oxygen species (ROS)-mediated death by stimulating SOD2 expression, increasing mitochondrial SOD2 activity and attenuating mitochondrial free radical ROS production, in association with increased mitochondrial capacity to produce H2O2, within the context of a more tumour stem cell-like phenotype. This effect can be reversed by the specific TrkA tyrosine kinase inhibitor GW441756, by the multi-kinase TrkA inhibitors K252a, CEP-701 and Gö6976, which inhibit SOD2 expression, and by siRNA knockdown of SOD2 expression, which restores the sensitivity of TrkAIII expressing SH-SY5Y cells to Rotenone, Paraquat and LY83583-induced mitochondrial free radical ROS production and ROS-mediated death. The data implicate the novel TrkAIII/SOD2 axis in promoting NB resistance to mitochondrial free radical-mediated death and staminality, and suggest that the combined use of TrkAIII and/or SOD2 inhibitors together with agents that induce mitochondrial free radical ROS-mediated death could provide a therapeutic advantage that may also target the stem cell niche in high TrkA expressing unfavourable NB. PMID:24736663

  12. Oxidative stress contributes to outcome severity in a Drosophila melanogaster model of classic galactosemia

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    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

  13. Effect of soil composition and dissolved organic matter on pesticide sorption.

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    Spark, K M; Swift, R S

    2002-10-21

    The effect of the solid and dissolved organic matter fractions, mineral composition and ionic strength of the soil solution on the sorption behaviour of pesticides were studied. A number of soils, chosen so as to have different clay mineral and organic carbon content, were used to study the sorption of the pesticides atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine), 2,4-D ((2,4-dichlorophenoxy)acetic acid), isoproturon (3-(4-isopropylphenyl)-1,1-dimethylurea) and paraquat (1,1'-dimethyl-4,4'-bipyridinium) in the presence of low and high levels of dissolved organic carbon and different background electrolytes. The sorption behaviour of atrazine, isoproturon and paraquat was dominated by the solid state soil components and the presence of dissolved organic matter had little effect. The sorption of 2,4-D was slightly affected by the soluble organic matter in the soil. However, this effect may be due to competition for adsorption sites between the pesticide and the soluble organic matter rather than due to a positive interaction between the pesticide and the soluble fraction of soil organic matter. It is concluded that the major factor governing the sorption of these pesticides is the solid state organic fraction with the clay mineral content also making a significant contribution. The dissolved organic carbon fraction of the total organic carbon in the soil and the ionic strength of the soil solution appear to have little or no effect on the sorption/transport characteristics of these pesticides over the range of concentrations studied.

  14. Acute intentional self-poisoning with a herbicide product containing fenoxaprop-P-ethyl, ethoxysulfuron and isoxadifen ethyl. A prospective observational study

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    ZAWAHIR, SHUKRY; ROBERTS, DARREN M.; PALANGASINGHE, CHATHURA; MOHAMED, FAHIM; EDDLESTON, MICHAEL; DAWSON, ANDREW H.; BUCKLEY, NICK A.; REN, LINGLING; MEDLEY, GREGORY A.; GAWARAMMANA, INDIKA

    2011-01-01

    BACKGROUND Herbicides are commonly ingested for self-harm; however, relatively little has been published on poisoning with herbicides other than paraquat and glyphosate. We report here a case series of patients with acute exposure to a combination herbicide (brand name Tiller Gold or Whip Super) containing the selective phenoxy herbicide fenoxaprop-P-ethyl, the sulfonylurea herbicide ethoxysulfuron and the safener isoxadifen ethyl. METHOD Clinical data on all patients presenting with Tiller Gold or Whip Super poisoning to two General Hospital in Sri Lanka from 2002-2008 were collected prospectively until discharge. RESULTS Eighty-six patients with a history of Tiller Gold or Whip Super ingestion were included. The median time to presentation was 4 hours post-ingestion (IQR 2 to 10 hrs) and the median volume ingested was 22.5ml (IQR: 20-60; n=64). Most patients demonstrated limited clinical signs of poisoning and none required mechanical ventilation or intensive care treatment. The main clinical features were an epigastric burning sensation and vomiting; however, most of those who vomited had received gastric lavage or forced emesis. Eight patients had a reduced level of consciousness on admission (GCS 9 -14) that resolved without intervention over several hours. Only symptomatic and supportive care was required. The median hospital stay was 1 day (IQR: 1 to 2) and the case fatality was zero (95% CI: zero to 4.2%). This low case fatality compared favorably with the case fatality of other common herbicides in our cohort: paraquat >40%, propanil >10%, 4-chloro-2-methylphenoxyacetic acid (MCPA) > 5% and glyphosate >2%. CONCLUSION This combination herbicide product appears to be safe in patients with acute self-poisoning, particularly in comparison with other herbicides, and causing few clinical features PMID:19663557

  15. Genome-wide association analysis of oxidative stress resistance in Drosophila melanogaster.

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    Allison L Weber

    Full Text Available Aerobic organisms are susceptible to damage by reactive oxygen species. Oxidative stress resistance is a quantitative trait with population variation attributable to the interplay between genetic and environmental factors. Drosophila melanogaster provides an ideal system to study the genetics of variation for resistance to oxidative stress.We used 167 wild-derived inbred lines of the Drosophila Genetic Reference Panel for a genome-wide association study of acute oxidative stress resistance to two oxidizing agents, paraquat and menadione sodium bisulfite. We found significant genetic variation for both stressors. Single nucleotide polymorphisms (SNPs associated with variation in oxidative stress resistance were often sex-specific and agent-dependent, with a small subset common for both sexes or treatments. Associated SNPs had moderately large effects, with an inverse relationship between effect size and allele frequency. Linear models with up to 12 SNPs explained 67-79% and 56-66% of the phenotypic variance for resistance to paraquat and menadione sodium bisulfite, respectively. Many genes implicated were novel with no known role in oxidative stress resistance. Bioinformatics analyses revealed a cellular network comprising DNA metabolism and neuronal development, consistent with targets of oxidative stress-inducing agents. We confirmed associations of seven candidate genes associated with natural variation in oxidative stress resistance through mutational analysis.We identified novel candidate genes associated with variation in resistance to oxidative stress that have context-dependent effects. These results form the basis for future translational studies to identify oxidative stress susceptibility/resistance genes that are evolutionary conserved and might play a role in human disease.

  16. Genome wide analysis of common and specific stress responses in adult drosophila melanogaster

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    Girardot, Fabrice; Monnier, Véronique; Tricoire, Hervé

    2004-01-01

    Background During their life, multicellular organisms are challenged with oxidative stress. It is generated by several reactive oxygen species (ROS), may limit lifespan and has been related to several human diseases. ROS can generate a wide variety of defects in many cellular components and thus the response of the organism challenged with oxidative stress may share some features with other stress responses. Conversely, in spite of recent progress, a complete functional analysis of the transcriptional responses to different oxidative stresses in model organisms is still missing. In addition, the functional significance of observed transcriptional changes is still elusive. Results We used oligonucleotide microarrays to address the specificities of transcriptional responses of adult Drosophila to different stresses induced by paraquat and H2O2, two oxidative stressors, and by tunicamycin which induces an endoplasmic reticulum (ER) stress. Both specific and common responses to the three stressors were observed and whole genome functional analysis identified several important classes of stress responsive genes. Within some functional classes, we observed that isozymes do not all behave similarly, which may reflect unsuspected functional specificities. Moreover, genetic experiments performed on a subset of lines bearing mutations in genes identified in microarray experiments showed that a significant number of these mutations may affect resistance of adult Drosophila to oxidative stress. Conclusions A long term common stress response to paraquat- or H2O2-induced oxidative stresses and ER stress is observed for a significant number of genes. Besides this common response, the unexpected complexity of the stress responses to oxidative and ER stresses in Drosophila, suggest significant specificities in protective properties between genes associated to the same functional classes. According to our functional analysis, a large part of the genome may play a role in protective

  17. Isolation of carboxylesterase (esterase FE4) from Apis cerana cerana and its role in oxidative resistance during adverse environmental stress.

    Science.gov (United States)

    Ma, Manli; Jia, Haihong; Cui, Xuepei; Zhai, Na; Wang, Hongfang; Guo, Xingqi; Xu, Baohua

    2017-10-30

    Carboxylesterases (CarEs) play vital roles in metabolising different physiologically important endogenous compounds and in detoxifying various harmful exogenous compounds in insects. Multiple studies of CarEs have focused on pesticide metabolism in insects, while few studies have aimed to identify CarE functions in oxidative resistance, particularly in Apis cerana cerana. In this study, we isolated a carboxylesterase gene, esterase FE4, from Apis cerana cerana and designated it towards an exploration of its roles as an antioxidant and in detoxification. We investigated AcceFE4 expression patterns in response to various stressors. A quantitative real-time PCR analysis revealed that AcceFE4 was up-regulated by H2O2, imidacloprid, and paraquat, and was down-regulated by 4 °C, UV radiation, CdCl2, and HgCl2. Additionally, the protein expression of this gene was down-regulated at 4 °C and up-regulated by H2O2. Disc diffusion assays showed that the AcceFE4 recombinant protein-expressing bacteria had a smaller killing zone than the control group with the paraquat, HgCl2 and cumyl hydroperoxide treatments. Moreover, when the gene was knocked down by RNA interference, we observed that multiple oxidant genes (i.e., AccSOD, AccGST, AccTrx, AccMsrA, and others) were down-regulated in the knockdown samples. Superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity levels were reduced in the knockdown samples relative to the control group. Finally, we measured the enzyme activity of carboxylesterase and found that the enzyme activity was also reduced in the silent samples. Together, these data suggest that AcceFE4 may be involved in the oxidative resistance response during adverse stress. Copyright © 2017. Published by Elsevier B.V.

  18. Aplicação em pré-colheita, de dessecante em duas cultivares de soja (Glycine max (L. Merril I - Efeitos imediatos sobre a germinação e produção de sementes

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    J.C. Durigan

    1980-12-01

    Full Text Available Plantas de soja das cultivares Santa Rosa e IAC-2 foram tratadas, em diferentes épocas após o início do florescimento, com o desse cante paraquat na dose de 2 l/ha do produto comercial. Objetivou-se avaliar os possíveis efeitos sobre a infecção de sementes por microorganismos prejudiciais a sua qualidade. As aplicações do produto foram feitas semanalmente a partir dos 72 e 75 dias após o início do fl orescimento, para as cultivares IAC -2 e Santa Rosa. respectivamente (teores de umidade das sementes de 56,8 e 57,5%. Para todas as épocas tratadas, existiam as suas respectivas comparações que não receberam o produto. As testemunhas foram colhidas seguindo-se os critérios usuais dos agricultores que trabalham com soja, aos 100 e 103 dias após o inicio do florescimento, respectivamente para as cultivares IAC-2 e Santa Rosa. A incidência de fungos prejudiciais à qualidade das sementes foi sempre menor para as parcelas que receberam dessecamento e aumentou com o retardamento da colheita, principalmente nas parcelas não tratadas.The plant desiccant paraquat was applied on soybean plants at different stages of development 1972 and 75 days after flowering, weekly and the harvested seeds examined as to fungus incidence. The data showed that the incidence of seed deteriorating fungi was always lower in the treated plots and increased when the harvest was delayed, mainly in the untreated plots.

  19. Aplicação em pré-colheita, de dessecante em duas cultivares de soja (Glycine max (L. Merril II - Efeitos sobre a incidência de fungos nas sementes

    Directory of Open Access Journals (Sweden)

    J.C. Durigan

    1980-12-01

    Full Text Available Plantas de soja das cultivares Santa Rosa e IAC-2 foram tratadas, em diferentes épocas após o início do florescimento, com o desse cante paraquat na dose de 2 l/ha do produto comercial. Objetivou-se avaliar os possíveis efeitos sobre a infecção de sementes por microorganismos prejudiciais a sua qualidade. As aplicações do produto foram feitas semanalmente a partir dos 72 e 75 dias após o início do fl orescimento, para as cultivares IAC -2 e Santa Rosa. respectivamente (teores de umidade das sementes de 56,8 e 57,5%. Para todas as épocas tratadas, existiam as suas respectivas comparações que não receberam o produto. As testemunhas foram colhidas seguindo-se os critérios usuais dos agricultores que trabalham com soja, aos 100 e 103 dias após o inicio do florescimento, respectivamente para as cultivares IAC-2 e Santa Rosa. A incidência de fungos prejudiciais à qualidade das sementes foi sempre menor para as parcelas que receberam dessecamento e au mentou com o retardamento da colheita, principalmente nas parcelas não tratadas.The plant desiccant paraquat was applied on soybean plants at different stages of development 1972 and 75 days after flowering, weekly and the harvested seeds examined as to fungus incidence. The data showed that the incidence of seed deteriorating fungi was always lower in the treated plots and increased when the harvest was delayed, mainly in the untreated plots.

  20. Oxidative Stress in Caenorhabditis elegans: Protective Effects of Spartin.

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    Timothy Truong

    Full Text Available Troyer syndrome is caused by a mutation in the SPG20 gene, which results in complete loss of expression of the protein spartin. We generated a genetic model of Troyer syndrome in worms to explore the locomotor consequences of a null mutation of the Caenorhabditis elegans SPG20 orthologue, F57B10.9, also known as spg-20. Spg-20 mutants showed decreased length, crawling speed, and thrashing frequency, and had a shorter lifespan than wild-type animals. These results suggest an age-dependent decline in motor function in mutant animals. The drug paraquat was used to induce oxidative stress for 4 days in the animals. We measured survival rate and examined locomotion by measuring crawling speed and thrashing frequency. After 4 days of paraquat exposure, 77% of wild-type animals survived, but only 38% of spg-20 mutant animals survived. Conversely, animals overexpressing spg-20 had a survival rate of 95%. We also tested lifespan after a 1 hour exposure to sodium azide. After a 24 hour recovery period, 87% of wild type animals survived, 57% of spg-20 mutant animals survived, and 82% of animals overexpressing spg-20 survived. In the behavioral assays, spg-20 mutant animals showed a significant decrease in both crawling speed and thrashing frequency compared with wild-type animals. Importantly, the locomotor phenotype for both crawling and thrashing was rescued in animals overexpressing spg-20. The animals overexpressing spg-20 had crawling speeds and thrashing frequencies similar to those of wild-type animals. These data suggest that the protein F57B10.9/SPG-20 might have a protective role against oxidative stress.

  1. Burrowing mayfly Ephemera orientalis (Ephemeroptera: Ephemeridae) as a new test species for pesticide toxicity.

    Science.gov (United States)

    Mo, Hyoung-Ho; Kim, Yongeun; Lee, Yun-Sik; Bae, Yeon Jae; Khim, Jong Seong; Cho, Kijong

    2016-09-01

    The potential of mayfly Ephemera orientalis McLachlan eggs and first-instar larvae in ecotoxicological testing was investigated. Both stages of E. orientalis showed high tolerance to various environmental variables, such as water temperature, pH, water hardness, and dissolved organic carbon. Toxicological assays were conducted with three insecticides (emamectin benzoate, endosulfan, and cypermethrin), one fungicide (mancozeb), and one herbicide (paraquat dichloride). The two toxicity endpoints for the assay were the 14-day egg median hatching rate (EHC50) in static and renewal exposure systems and 24-h median larval mortality (LC50). Cypermethrin was the most toxic to both eggs (EHC50 in static system = 36.9 μg/L; EHC50 in renewal system < 0.15 μg/L) and larvae (LC50 = 4.5 μg/L), and paraquat dichloride was the least toxic to eggs (EHC50 in static system = 54,359.8 μg/L; EHC50 in renewal system = 49541.3 μg/L) and larvae (LC50 = 9259.5 μg/L). The results were compared to literature data of Daphnia magna Straus and Cloeon dipterum Linnaeus to determine its relative sensitivity to pesticides. These three species had different toxicities to the tested pesticides, especially according to the exposure system. E. orientalis eggs in the static system were found to be less sensitive were D. magna and C. dipterum, but eggs in the renewal system and larvae had similar or higher sensitivities to the tested pesticides. The results revealed that this species has potential for use in ecotoxicological testing of pesticides. Because of its geographic distribution, E. orientalis may be used as an alternative or complementary test species for ecotoxicological studies in Northeast Asian countries, where natural populations of the international standard species, D. magna, are rarely found.

  2. Environmental exposure to pesticides and the risk of Parkinson's disease in the Netherlands.

    Science.gov (United States)

    Brouwer, Maartje; Huss, Anke; van der Mark, Marianne; Nijssen, Peter C G; Mulleners, Wim M; Sas, Antonetta M G; van Laar, Teus; de Snoo, Geert R; Kromhout, Hans; Vermeulen, Roel C H

    2017-10-01

    Exposure to pesticides has been linked to Parkinson's disease (PD), although associations between specific pesticides and PD have not been well studied. Residents of rural areas can be exposed through environmental drift and volatilization of agricultural pesticides. Our aim was to investigate the association between lifetime environmental exposure to individual pesticides and the risk of PD, in a national case-control study. Environmental exposure to pesticides was estimated using a spatio-temporal model, based on agricultural crops around the residential address. Distance up to 100m from the residence was considered most relevant, considering pesticide drift potential of application methods used in the Netherlands. Exposure estimates were generated for 157 pesticides, used during the study period, of which four (i.e. paraquat, maneb, lindane, benomyl) were considered a priori relevant for PD. A total of 352 PD cases and 607 hospital-based controls were included. No significant associations with PD were found for the a priori pesticides. In a hypothesis generating analysis, including 153 pesticides, increased risk of PD was found for 21 pesticides, mainly used on cereals and potatoes. Results were suggestive for an association between bulb cultivation and PD. For paraquat, risk estimates for the highest cumulative exposure tertile were in line with previously reported elevated risks. Increased risk of PD was observed for exposure to (a cluster of) pesticides used on rotating crops. High correlations limited our ability to identify individual pesticides responsible for this association. This study provides some evidence for an association between environmental exposure to specific pesticides and the risk of PD, and generates new leads for further epidemiological and mechanistic research. Copyright © 2017. Published by Elsevier Ltd.

  3. 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

  4. Identificação de biótipos de azevém (Lolium multiflorum resistentes ao herbicida glyphosate em pomares de maçã Identification of glyphosate-resistant ryegrass (Lolium multiflorum biotypes in apple orchards

    Directory of Open Access Journals (Sweden)

    L. Vargas

    2004-12-01

    Full Text Available O glyphosate é um herbicida de amplo espectro utilizado há mais de 15 anos em pomares de maçã na região de Vacaria-RS, para manejo da vegetação nas linhas da cultura. São realizadas, em geral, três a quatro aplicações por ciclo e a dose normalmente utilizada é de 720 a 1.080 g e.a. ha-1 de glyphosate (2 a 3 L ha-1 do produto comercial. O azevém (Lolium multiflorum é uma planta daninha comum em pomares e, tradicionalmente, sensível ao glyphosate. Entretanto, nos últimos anos a ocorrência de plantas de azevém que, após receberem o tratamento com glyphosate, não manifestam sintomas significativos de toxicidade sugere que elas adquiriram resistência ao produto. Assim, com o objetivo de avaliar a resposta de uma população de plantas de azevém ao glyphosate, foram realizados três experimentos: um em campo e dois em casa de vegetação. No experimento em campo os tratamentos avaliados constaram de doses crescentes de glyphosate (0, 360, 720, 1.440, 2.880, 5.760 e 11.520 g e.a. ha-1, e os herbicidas paraquat, glufosinate, haloxyfop e diclofop foram empregados como produtos-padrão, aplicados em dois estádios vegetativos do azevém. No experimento em casa de vegetação, os tratamentos constaram de doses crescentes de glyphosate (0, 360, 720, 1.440, 2.880 e 5.760 g e.a. ha-1 mais os herbicidas testemunhas, aplicados sobre plantas do biótipo considerado resistente e de um sensível. No segundo experimento realizado em casa de vegetação foram avaliados tratamentos contendo glyphosate (720, 1.440, 2.880, 720 + 720 e 720 + 1.440 g e.a. ha-1, em aplicações únicas e seqüenciais, mais os herbicidas paraquat, glufosinate, haloxyfop, clethodim, sethoxydim, diclofop, fenoxaprop, fluazifop, paraquat + diuron, atrazine + simazine, trifluralin e metolachlor. A toxicidade dos tratamentos herbicidas foi avaliada aos 15, 30 e 45 DAT (dias após tratamento. Os resultados obtidos nos experimentos em campo e em casa de vegetação, de forma

  5. Utilização de acetochlor e atrazine aplicados em mistura de tanque com dessecantes no sistema de plantio direto Reaction of the herbicides acetochlor and atrazine applied in tank mixtures with desiccants in no-till system

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    Benedito N. Rodrigues

    2000-08-01

    Full Text Available A mistura em tanque de herbicidas dessecantes com residuais tem sido utilizada com frequencia pelos agricultores no sistema de plantio direto. Sabe-se, no entanto, que alguns herbicidas residuais têm problemas de retenção na palha quando utilizados isoladamente em préemergência nesse sistema. O objetivo do presente trabalho, foi estudar o comportamento dos herbicidas residuais atrazine e acetochlor em mistura com dessecantes no manejo em plantio direto. Para tal, foi instalado um experimento em blocos ao acaso com parcelas subdivididas e quatro repetições. Os tratamentos, alocados na parcela, em número de nove, foram constituidos pelas seguintes misturas de herbicidas: 1 acetochlor + glyphosate; 2 acetochlor + glyphosate + 2,4D; 3 acetochlor + paraquat; 4 acetochlor + paraquat + 2,4D; 5 atrazine + glyphosate; 6 atrazine + glyphosate + 2,4D; 7 atrazine + paraquat; 8 atrazine + óleo vegetal; 9 testemunha não tratada. Os tratamentos da sub parcela, em número de dois, foram constituidos pelas modalidades de aplicação dos herbicidas na cobertura vegetal: 1 aplicação com a cobertura "em pé"; 2 aplicação com a cobertura "rolada". A cobertura vegetal de inverno era formada pela consorciação de aveia-preta + ervilhaca comum. Os resultados mostraram que o controle de Brachiaria plantaginea, Euphorbia heterophylla e Bidens pilosa foi melhor efetuado com os tratamentos onde entrou o atrazine. De maneira geral, o controle obtido na modalidade "em pé," foi melhor do que na modalidade "rolada," principalmente nos tratamentos com acetochlor. A análise cromatográfica de resíduos feita em amostras de solo retiradas do experimento antes e após uma chuva de 41mm ocorrida 24 horas após a aplicação dos tratamentos, mostrou que menos de 6 % do acetochlor aplicado foi detectado no solo, em ambas as modalidades de aplicação. Quanto ao atrazine, no entanto, mais de 78 % do total aplicado foi detectado no solo após a chuva na modalidade

  6. Purification and Characterization of [NiFe]-Hydrogenase of Shewanella oneidensis MR-1

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Liang; Belchik, Sara M.; Plymale, Andrew E.; Heald, Steve M.; Dohnalkova, Alice; Sybirna, Kateryna; Bottin, Herve; Squier, Thomas C.; Zachara, John M.; Fredrickson, Jim K.

    2011-08-02

    The γ-proteobacterium Shewanella oneidensis MR-1 possesses a periplasmic [NiFe]-hydrogenase (MR-1 [NiFe]-H2ase) that was implicated in both H2 production and oxidation as well as technetium [Tc(VII)] reduction. To characterize the roles of MR-1 [NiFe]-H2ase in these proposed reactions, the genes encoding both subunits of MR-1 [NiFe]-H2ase were cloned into a protein expression vector. The resulting plasmid was transformed into a MR-1 mutant deficient in H2 formation. Expression of MR-1 [NiFe]-H2ase in trans restored the mutant’s ability to produce H2 at 37% of that for wild type. Following expression, MR-1 [NiFe]-H2ase was purified to near homogeneity. The purified MR-1 [NiFe]-H2ase could couple H2 oxidation to reduction of Tc(VII) and methyl viologen directly. Change of the buffers used affected MR-1 [NiFe]-H2ase-mediated Tc(VII) but not methyl viologen reductions. Under the conditions tested, Tc(VII) reduction was complete in Tris buffer but not in HEPES buffer. The reduced Tc(IV) was soluble in Tris buffer but insoluble in HEPES buffer. Transmission electron microscopy analysis revealed that Tc(IV) precipitates formed in HEPES buffer were packed with crystallites. Although X-ray absorption near-edge spectroscopy measurements confirmed that the reduction products found in both buffers were Tc(IV), extended X-ray adsorption fine-structure measurements revealed that these products were very different. While the product in Tris buffer could not be determined, the Tc(IV) product in HEPES buffer was very similar to Tc(IV)O2•nH2O. These results shows for the first time that MR-1 [NiFe]-H2ase is a bidirectional enzyme that catalyzes both H2 formation and oxidation as well as Tc(VII) reduction directly by coupling H2 oxidation.

  7. Temperature dependence of nitrate reductase in the psychrophilic unicellular alga Koliella antarctica and the mesophilic alga Chlorella sorokiniana.

    Science.gov (United States)

    di Rigano, Vittoria Martino; Vona, Vincenza; Lobosco, Ornella; Carillo, Petronia; Lunn, John E; Carfagna, Simona; Esposito, Sergio; Caiazzo, Marianna; Rigano, Carmelo

    2006-07-01

    Temperature responses of nitrate reductase (NR) were studied in the psychrophilic unicellular alga, Koliella antarctica, and in the mesophilic species, Chlorella sorokiniana. Enzymes from both species were purified to near homogeneity by Blue Sepharose (Pharmacia, Uppsala, Sweden) affinity chromatography and high-resolution anion-exchange chromatography (MonoQ; Pharmacia; Uppsala, Sweden). Both enzymes have a subunit molecular mass of 100 kDa, and K. antarctica NR has a native molecular mass of 367 kDa. NR from K. antarctica used both NADPH and NADH, whereas NR from C. sorokiniana used NADH only. Both NRs used reduced methyl viologen (MVH) or benzyl viologen (BVH). In crude extracts, maximal NADH and MVH-dependent activities of cryophilic NR were found at 15 and 35 degrees C, respectively, and retained 77 and 62% of maximal activity, respectively, at 10 degrees C. Maximal NADH and MVH-dependent activities of mesophilic NR, however, were found at 25 and 45 degrees C, respectively, with only 33 and 23% of maximal activities being retained at 10 degrees C. In presence of 2 microM flavin adenine dinucleotide (FAD), activities of cryophilic NADH:NR and mesophilic NADH:NR were stable up to 25 and 35 degrees C, respectively. Arrhenius plots constructed with cryophilic and mesophilic MVH:NR rate constants, in both presence or absence of FAD, showed break points at 15 and 25 degrees C, respectively. Essentially, similar results were obtained for purified enzymes and for activities measured in crude extracts. Factors by which the rate increases by raising temperature 10 degrees C (Q10) and apparent activation energy (E(a)) values for NADH and MVH activities measured in enzyme preparations without added FAD differed slightly from those measured with FAD. Overall thermal features of the NADH and MVH activities of the cryophilic NR, including optimal temperatures, heat inactivation (with/without added FAD) and break-point temperature in Arrhenius plots, are all shifted by about

  8. GhWRKY15, a member of the WRKY transcription factor family identified from cotton (Gossypium hirsutum L., is involved in disease resistance and plant development

    Directory of Open Access Journals (Sweden)

    Yu Feifei

    2012-08-01

    Full Text Available Abstract Background As a large family of regulatory proteins, WRKY transcription factors play essential roles in the processes of adaptation to diverse environmental stresses and plant growth and development. Although several studies have investigated the role of WRKY transcription factors during these processes, the mechanisms underlying the function of WRKY members need to be further explored, and research focusing on the WRKY family in cotton crops is extremely limited. Results In the present study, a gene encoding a putative WRKY family member, GhWRKY15, was isolated from cotton. GhWRKY15 is present as a single copy gene, and a transient expression analysis indicated that GhWRKY15 was localised to the nucleus. Additionally, a group of cis-acting elements associated with the response to environmental stress and plant growth and development were detected in the promoter. Consistently, northern blot analysis showed that GhWRKY15 expression was significantly induced in cotton seedlings following fungal infection or treatment with salicylic acid, methyl jasmonate or methyl viologen. Furthermore, GhWRKY15-overexpressing tobacco exhibited more resistance to viral and fungal infections compared with wild-type tobacco. The GhWRKY15-overexpressing tobacco also exhibited increased RNA expression of several pathogen-related genes, NONEXPRESSOR OF PR1, and two genes that encode enzymes involved in ET biosynthesis. Importantly, increased activity of the antioxidant enzymes POD and APX during infection and enhanced expression of NtAPX1 and NtGPX in transgenic tobacco following methyl viologen treatment were observed. Moreover, GhWRKY15 transcription was greater in the roots and stems compared with the expression in the cotyledon of cotton, and the stems of transgenic plants displayed faster elongation at the earlier shooting stages compared with wide type tobacco. Additionally, exposure to abiotic stresses, including cold, wounding and drought, resulted in

  9. Ellipsometric and Electrochemical Characterization of Charge Transport in Electroactive Polymers and of the Surface Phase Produced by Electrochemical Activation of Glassy Carbon Electrodes

    Science.gov (United States)

    Kepley, Larry Joe

    1990-01-01

    In situ ellipsometry was used to study the electrodeposition of polymer films formed by oxidation of bipyrazine, polyvinylferrocene (PVF), and aniline; the deposition of a viologen-containing siloxane polymer (PQ^{2+/+}) formed by electroreduction of N,N^' -bis (-3-(trimethoxysilyl)propyl) -4,4^ '-bipyridinium dichloride (I) solutions and by spin-casting solutions of I; and the oxidation-dependent swelling of spin-cast films of two structurally similar, ferrocene-containing polyamides. Electrodeposited films displayed good optical characteristics (i.e., high reflectivity, uniform coverage, and homogeneity) for thicknesses up to 400 nm in some cases. Nonideal illipsometric behavior was observed when film morphology varied with film growth. The complex refractive index, film thickness, and the viologen and ferrocene concentrations in the films were measured as a function of oxidation state, both during depositions and after transferring coated-electrodes into blank electrolyte solutions. The voltammetry of the redox polymers was studied and charge-transport modeled by finite -difference simulations of charge diffusion and diffusion coupled to dimerization/monomerization reactions. Equations were derived for linear-sweep voltammetry of a reversible couple in equilibrium with its dimer in a thin-layer cell. Ellipsometric data during electrolysis of the redox films by potential sweeps and steps were compared to theoretical curves for diffusional transport to determine the mechanism of charge transport and to optically measure its rate. The influence of redox-induced thickness changes and solvent sorption on charge transport and voltammetric behavior is described. The electrochemical activation of glassy carbon electrodes for electrolysis of aromatic molecules, such as catechol and hydroquinone, was studied by combined ellipsometric and voltammetric measurements. Ellipsometry was used to detect the anodic growth of nearly transparent layer which activated the surface. X

  10. GhWRKY15, a member of the WRKY transcription factor family identified from cotton (Gossypium hirsutum L.), is involved in disease resistance and plant development.

    Science.gov (United States)

    Yu, Feifei; Huaxia, Yifeng; Lu, Wenjing; Wu, Changai; Cao, Xuecheng; Guo, Xingqi

    2012-08-12

    As a large family of regulatory proteins, WRKY transcription factors play essential roles in the processes of adaptation to diverse environmental stresses and plant growth and development. Although several studies have investigated the role of WRKY transcription factors during these processes, the mechanisms underlying the function of WRKY members need to be further explored, and research focusing on the WRKY family in cotton crops is extremely limited. In the present study, a gene encoding a putative WRKY family member, GhWRKY15, was isolated from cotton. GhWRKY15 is present as a single copy gene, and a transient expression analysis indicated that GhWRKY15 was localised to the nucleus. Additionally, a group of cis-acting elements associated with the response to environmental stress and plant growth and development were detected in the promoter. Consistently, northern blot analysis showed that GhWRKY15 expression was significantly induced in cotton seedlings following fungal infection or treatment with salicylic acid, methyl jasmonate or methyl viologen. Furthermore, GhWRKY15-overexpressing tobacco exhibited more resistance to viral and fungal infections compared with wild-type tobacco. The GhWRKY15-overexpressing tobacco also exhibited increased RNA expression of several pathogen-related genes, NONEXPRESSOR OF PR1, and two genes that encode enzymes involved in ET biosynthesis. Importantly, increased activity of the antioxidant enzymes POD and APX during infection and enhanced expression of NtAPX1 and NtGPX in transgenic tobacco following methyl viologen treatment were observed. Moreover, GhWRKY15 transcription was greater in the roots and stems compared with the expression in the cotyledon of cotton, and the stems of transgenic plants displayed faster elongation at the earlier shooting stages compared with wide type tobacco. Additionally, exposure to abiotic stresses, including cold, wounding and drought, resulted in the accumulation of GhWRKY15 transcripts

  11. A P-Loop NTPase Regulates Quiescent Center Cell Division and Distal Stem Cell Identity through the Regulation of ROS Homeostasis in Arabidopsis Root.

    Science.gov (United States)

    Yu, Qianqian; Tian, Huiyu; Yue, Kun; Liu, Jiajia; Zhang, Bing; Li, Xugang; Ding, Zhaojun

    2016-09-01

    Reactive oxygen species (ROS) are recognized as important regulators of cell division and differentiation. The Arabidopsis thaliana P-loop NTPase encoded by APP1 affects root stem cell niche identity through its control of local ROS homeostasis. The disruption of APP1 is accompanied by a reduction in ROS level, a rise in the rate of cell division in the quiescent center (QC) and the promotion of root distal stem cell (DSC) differentiation. Both the higher level of ROS induced in the app1 mutant by exposure to methyl viologen (MV), and treatment with hydrogen peroxide (H2O2) rescued the mutant phenotype, implying that both the increased rate of cell division in the QC and the enhancement in root DSC differentiation can be attributed to a low level of ROS. APP1 is expressed in the root apical meristem cell mitochondria, and its product is associated with ATP hydrolase activity. The key transcription factors, which are defining root distal stem niche, such as SCARECROW (SCR) and SHORT ROOT (SHR) are both significantly down-regulated at both the transcriptional and protein level in the app1 mutant, indicating that SHR and SCR are important downstream targets of APP1-regulated ROS signaling to control the identity of root QC and DSCs.

  12. Comparative Analyses of Cu-Zn Superoxide Dismutase (SOD1) and Thioredoxin Reductase (TrxR) at the mRNA Level between Apis mellifera L. and Apis cerana F. (Hymenoptera: Apidae) Under Stress Conditions.

    Science.gov (United States)

    Koo, Hyun-Na; Lee, Soon-Gyu; Yun, Seung-Hwan; Kim, Hyun Kyung; Choi, Yong Soo; Kim, Gil-Hah

    2016-01-01

    This study compared stress-induced expression of Cu-Zn superoxide dismutase (SOD1) and thioredoxin reductase (TrxR) genes in the European honeybee Apis mellifera L. and Asian honeybee Apis cerana F. Expression of both SOD1 and TrxR rapidly increased up to 5 h after exposure to cold (4 °C) or heat (37 °C) treatment and then gradually decreased, with a stronger effect induced by cold stress in A. mellifera compared with A. cerana. Injection of stress-inducing substances (methyl viologen, [MV] and H2O2) also increased SOD1 and TrxR expression in both A. mellifera and A. cerana, and this effect was more pronounced with MV than H2O2. Additionally, we heterologously expressed the A. mellifera and A. cerana SOD1 and TrxR proteins in an Escherichia coli expression system, and detection by SDS-PAGE, confirmed by Western blotting using anti-His tag antibodies, revealed bands at 16 and 60 kDa, respectively. Our results show that the expression patterns of SOD1 and TrxR differ between A. mellifera and A. cerana under conditions of low or high temperature as well as oxidative stress. © The Author 2016. Published by Oxford University Press on behalf of the Entomological Society of America.

  13. Down-regulation of OsSPX1 causes high sensitivity to cold and oxidative stresses in rice seedlings.

    Directory of Open Access Journals (Sweden)

    Chunchao Wang

    Full Text Available Rice SPX domain gene, OsSPX1, plays an important role in the phosphate (Pi signaling network. Our previous work showed that constitutive overexpression of OsSPX1 in tobacco and Arabidopsis plants improved cold tolerance while also decreasing total leaf Pi. In the present study, we generated rice antisense and sense transgenic lines of OsSPX1 and found that down-regulation of OsSPX1 caused high sensitivity to cold and oxidative stresses in rice seedlings. Compared to wild-type and OsSPX1-sense transgenic lines, more hydrogen peroxide accumulated in seedling leaves of OsSPX1-antisense transgenic lines for controls, cold and methyl viologen (MV treatments. Glutathione as a ROS scavenger could protect the antisense transgenic lines from cold and MV stress. Rice whole genome GeneChip analysis showed that some oxidative-stress marker genes (e.g. glutathione S-transferase and P450s and Pi-signaling pathway related genes (e.g. OsPHO2 were significantly down-regulated by the antisense of OsSPX1. The microarray results were validated by real-time RT-PCR. Our study indicated that OsSPX1 may be involved in cross-talks between oxidative stress, cold stress and phosphate homeostasis in rice seedling leaves.

  14. Concerted intercalation and minor groove recognition of DNA by a homodimeric thiazole orange dye.

    Science.gov (United States)

    Bunkenborg, J; Gadjev, N I; Deligeorgiev, T; Jacobsen, J P

    2000-01-01

    The thiazole orange dye TOTO binds to double-stranded DNA (dsDNA) by a sequence selective bis-intercalation. Each chromophore is sandwiched between two base pairs in a (5'-CpT-3'):(5'-ApG-3') site, and the linker spans two base pairs in the minor groove. We have used one- and two-dimensional NMR spectroscopy to examine the dsDNA binding of an analogue of TOTO in which the linker has been modified to contain a bipyridyl group (viologen) that has minor groove binding properties. We have investigated the binding of this analogue, called TOTOBIPY, to three different dsDNA sequences containing a 5'-CTAG-3', a 5'-CTTAG-3', and a 5'-CTATAG-3' sites, respectively, demonstrating that TOTOBIPY prefers to span three base pairs. The many intermolecular NOE connectivities between TOTOBIPY and the d(CGCTTAGCG):d(CGCTAAGCG) oligonucleotide in the complex shows that the bipyridyl-containing linker is positioned in the minor groove and spans three base pairs. Consequently, we have succeeded in designing and synthesizing a ligand that recognizes an extended recognition sequence of dsDNA as the result of a concerted intercalation and minor groove binding mode.

  15. Effect of different modifications of BEA-zeolites on operational characteristics of conductometric biosensor.

    Science.gov (United States)

    Kucherenko, I S; Soldatkin, Capital O Cyrillic О; Soy, E; Kirdeciler, K; Öztürk, S; Akata, B; Jaffrezic-Renault, N; Soldatkin, A P; Dzyadevych, S V

    2012-08-01

    Effect of different modifications of zeolite Na(+)-BEA on working characteristics of urease-based conductometric biosensor was studied. As the biosensor sensitive elements were used bioselective membranes based on urease and various zeolites immobilised with bovine serum albumin on the surface of conductometric transducers. Influence of zeolites on sensitivity of urea biosensor was investigated as well as reproducibility of biosensor signal and reproducibility of activity of the bioselective element after different variants of urease immobilisation on the surface of conductometric transducer. The biosensors based on zeolites (NH4(+)-BEA 30 and H(+)-BEA 30) were shown to be the most sensitive. Concentration of these zeolites in the bioselective membrane was optimized. Use of zeolites modified with methyl viologen and silver was ascertained to be of no prospect for urea conductometric biosensors. It was demonstrated that characteristics of urea biosensors can be regulated, varying zeolites modifications and their concentrations in bioselective membranes. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Anastatica hierochuntica, an Arabidopsis Desert Relative, Is Tolerant to Multiple Abiotic Stresses and Exhibits Species-Specific and Common Stress Tolerance Strategies with Its Halophytic Relative, Eutrema (Thellungiella) salsugineum

    Science.gov (United States)

    Eshel, Gil; Shaked, Ruth; Kazachkova, Yana; Khan, Asif; Eppel, Amir; Cisneros, Aroldo; Acuna, Tania; Gutterman, Yitzhak; Tel-Zur, Noemi; Rachmilevitch, Shimon; Fait, Aaron; Barak, Simon

    2017-01-01

    The search for novel stress tolerance determinants has led to increasing interest in plants native to extreme environments – so called “extremophytes.” One successful strategy has been comparative studies between Arabidopsis thaliana and extremophyte Brassicaceae relatives such as the halophyte Eutrema salsugineum located in areas including cold, salty coastal regions of China. Here, we investigate stress tolerance in the desert species, Anastatica hierochuntica (True Rose of Jericho), a member of the poorly investigated lineage III Brassicaceae. We show that A. hierochuntica has a genome approximately 4.5-fold larger than Arabidopsis, divided into 22 diploid chromosomes, and demonstrate that A. hierochuntica exhibits tolerance to heat, low N and salt stresses that are characteristic of its habitat. Taking salt tolerance as a case study, we show that A. hierochuntica shares common salt tolerance mechanisms with E. salsugineum such as tight control of shoot Na+ accumulation and resilient photochemistry features. Furthermore, metabolic profiling of E. salsugineum and A. hierochuntica shoots demonstrates that the extremophytes exhibit both species-specific and common metabolic strategies to cope with salt stress including constitutive up-regulation (under control and salt stress conditions) of ascorbate and dehydroascorbate, two metabolites involved in ROS scavenging. Accordingly, A. hierochuntica displays tolerance to methyl viologen-induced oxidative stress suggesting that a highly active antioxidant system is essential to cope with multiple abiotic stresses. We suggest that A. hierochuntica presents an excellent extremophyte Arabidopsis relative model system for understanding plant survival in harsh desert conditions. PMID:28144244

  17. Production of L-malic acid with fixation of HCO3(-) by malic enzyme-catalyzed reaction based on regeneration of coenzyme on electrode modified by layer-by-layer self-assembly method.

    Science.gov (United States)

    Zheng, Haitao; Ohno, Yoko; Nakamori, Toshihiko; Suye, Shin-Ichiro

    2009-01-01

    Malic enzyme prepared and purified from Brevundimonas diminuta IFO13182 catalyzed the decarboxylation reaction of malate to pyruvate and CO2 using NAD+ as the coenzyme, and the reverse reaction was used in the present study for L-malic acid production with fixation of HCO3(-) as a model compound for carbon source. The L-malic acid production was based on electrochemical regeneration of NADH on a carbon plate electrode modified by layer-by-layer adsorption of polymer-bound mediator (Alginic acid bound viologen derivative, Alg-V), polymer-bound coenzyme (Alginic acid bound NAD+, Alg-NAD+), and lipoamide dehydrogenase (LipDH). Electrochemical reduction of immobilized NAD+ catalyzed by LipDH in a multilayer film was achieved, and the L-malic acid production with HCO3(-) fixation system with layer-by-layer immobilization of Alg-V/LipDH/Alg-NAD+/malic enzyme multilayer film on the electrode gave an L-malic acid production of nearly 11.9 mmol and an HCO3(-) fixation rate of nearly 47.4% in a buffer containing only KHCO3 and pyruvic acid potassium salt, using a cation exchange membrane. The total turnover number of NADH within 48 h was about 19,000, which suggests that efficient NADH regeneration and fast electron transfer were achieved within the multilayer film, and that the modified electrode is a potential method for the fixation of HCO3(-) without addition of free coenzyme.

  18. Influence of Proton Acceptors on the Proton-Coupled Electron Transfer Reaction Kinetics of a Ruthenium-Tyrosine Complex.

    Science.gov (United States)

    Lennox, J Christian; Dempsey, Jillian L

    2017-11-22

    A polypyridyl ruthenium complex with fluorinated bipyridine ligands and a covalently bound tyrosine moiety was synthesized, and its photo-induced proton-coupled electron transfer (PCET) reactivity in acetonitrile was investigated with transient absorption spectroscopy. Using flash-quench methodology with methyl viologen as an oxidative quencher, a Ru 3+ species is generated that is capable of initiating the intramolecular PCET oxidation of the tyrosine moiety. Using a series of substituted pyridine bases, the reaction kinetics were found to vary as a function of proton acceptor concentration and identity, with no significant H/D kinetic isotope effect. Through analysis of the kinetics traces and comparison to a control complex without the tyrosine moiety, PCET reactivity was found to proceed through an equilibrium electron transfer followed by proton transfer (ET-PT) pathway in which irreversible deprotonation of the tyrosine radical cation shifts the ET equilibrium, conferring a base dependence on the reaction. Comprehensive kinetics modeling allowed for deconvolution of complex kinetics and determination of rate constants for each elementary step. Across the five pyridine bases explored, spanning a range of 4.2 pK a units, a linear free-energy relationship was found for the proton transfer rate constant with a slope of 0.32. These findings highlight the influence that proton transfer driving force exerts on PCET reaction kinetics.

  19. Salicylic acid is involved in the Nb-mediated defense responses to Potato virus X in Solanum tuberosum.

    Science.gov (United States)

    Sánchez, Gerardo; Gerhardt, Nadia; Siciliano, Florencia; Vojnov, Adrián; Malcuit, Isabelle; Marano, María Rosa

    2010-04-01

    To evaluate the role of salicylic acid (SA) in Nb-mediated hypersensitive resistance to Potato virus X (PVX) avirulent strain ROTH1 in Solanum tuberosum, we have constructed SA-deficient transgenic potato plant lines by overexpressing the bacterial enzyme salicylate hydroxylase (NahG), which degrades SA. Evaluation of these transgenic lines revealed hydrogen peroxide accumulation and spontaneous lesion formation in an age- and light-dependent manner. In concordance, NahG potato plants were more sensitive to treatment with methyl viologen, a reactive oxygen species-generating compound. In addition, when challenged with PVX ROTH1, NahG transgenic lines showed a decreased disease-resistance response to infection and were unable to induce systemic acquired resistance. However, the avirulent viral effector, the PVX 25-kDa protein, does induce expression of the pathogenesis-related gene PR-1a in NahG potato plants. Taken together, our data indicate that SA is involved in local and systemic defense responses mediated by the Nb gene in Solanum tuberosum. This is the first report to show that basal levels of SA correlate with hypersensitive resistance to PVX.

  20. High performance unipolar MoTe2 field effect transistors enabled by doping and Al2O3 capping

    Science.gov (United States)

    Qu, Deshun; Liu, Xiaochi; Ahmed, Faisal; Yoo, Won Jong

    We carry out the first systematic experiment on carrier type modulation of MoTe2 FET in this work. unipolar p- and n-type MoTe2 FETs with 105 and 106 on-off ratios are achieved through rapid thermal annealing (RTA) and Benzyl Viologen (BV) doping respectively. By varying the vacuum level in RTA chamber before annealing and BV dopant concentration, annealing condition, both hole and electron doping concentration can be modulated in a wide range from slight doping to degenerate like doping. Furthermore, Al2O3 is deposited onto the device surfaces for the mobility engineering. Hole and electron mobilities are improved to 62 cm2/Vs and 82 cm2/Vs respectively after Al2O3 capping; they are among the highest carrier mobilities of MoTe2 transistors ever obtained. A lateral homogeneous MoTe2 p-n diode is fabricated combining the electron and hole doping techniques, the device displays excellent diode properties with a high rectification ratio of 104 at 0 gate bias and an ideality factor of 1.2. This work was supported by the Global Research Laboratory and Global Frontier R&D Programs at the Center for Hybrid Interface Materials, both funded by the Ministry of Science, ICT & Future Planning via the National Research Foundation of Korea (NRF).

  1. Transgenic Alfalfa Plants Expressing the Sweetpotato Orange Gene Exhibit Enhanced Abiotic Stress Tolerance

    Science.gov (United States)

    Wang, Zhi; Ke, Qingbo; Kim, Myoung Duck; Kim, Sun Ha; Ji, Chang Yoon; Jeong, Jae Cheol; Lee, Haeng-Soon; Park, Woo Sung; Ahn, Mi-Jeong; Li, Hongbing; Xu, Bingcheng; Deng, Xiping; Lee, Sang-Hoon; Lim, Yong Pyo; Kwak, Sang-Soo

    2015-01-01

    Alfalfa (Medicago sativa L.), a perennial forage crop with high nutritional content, is widely distributed in various environments worldwide. We recently demonstrated that the sweetpotato Orange gene (IbOr) is involved in increasing carotenoid accumulation and enhancing resistance to multiple abiotic stresses. In this study, in an effort to improve the nutritional quality and environmental stress tolerance of alfalfa, we transferred the IbOr gene into alfalfa (cv. Xinjiang Daye) under the control of an oxidative stress-inducible peroxidase (SWPA2) promoter through Agrobacterium tumefaciens-mediated transformation. Among the 11 transgenic alfalfa lines (referred to as SOR plants), three lines (SOR2, SOR3, and SOR8) selected based on their IbOr transcript levels were examined for their tolerance to methyl viologen (MV)-induced oxidative stress in a leaf disc assay. The SOR plants exhibited less damage in response to MV-mediated oxidative stress and salt stress than non-transgenic plants. The SOR plants also exhibited enhanced tolerance to drought stress, along with higher total carotenoid levels. The results suggest that SOR alfalfa plants would be useful as forage crops with improved nutritional value and increased tolerance to multiple abiotic stresses, which would enhance the development of sustainable agriculture on marginal lands. PMID:25946429

  2. A cellulose synthase-like protein is required for osmotic stress tolerance in Arabidopsis

    KAUST Repository

    Zhu, Jianhua

    2010-04-16

    Osmotic stress imposed by soil salinity and drought stress significantly affects plant growth and development, but osmotic stress sensing and tolerance mechanisms are not well understood. Forward genetic screens using a root-bending assay have previously identified salt overly sensitive (sos) mutants of Arabidopsis that fall into five loci, SOS1 to SOS5. These loci are required for the regulation of ion homeostasis or cell expansion under salt stress, but do not play a major role in plant tolerance to the osmotic stress component of soil salinity or drought. Here we report an additional sos mutant, sos6-1, which defines a locus essential for osmotic stress tolerance. sos6-1 plants are hypersensitive to salt stress and osmotic stress imposed by mannitol or polyethylene glycol in culture media or by water deficit in the soil. SOS6 encodes a cellulose synthase-like protein, AtCSLD5. Only modest differences in cell wall chemical composition could be detected, but we found that sos6-1 mutant plants accumulate high levels of reactive oxygen species (ROS) under osmotic stress and are hypersensitive to the oxidative stress reagent methyl viologen. The results suggest that SOS6/AtCSLD5 is not required for normal plant growth and development but has a critical role in osmotic stress tolerance and this function likely involves its regulation of ROS under stress. © 2010 Blackwell Publishing Ltd.

  3. Acceleration of Long-Range Photoinduced Electron Transfer through DNA by Hydroxyquinolines as Artificial Base Pairs.

    Science.gov (United States)

    Bätzner, Effi; Liang, Yu; Schweigert, Caroline; Unterreiner, Andreas-Neil; Wagenknecht, Hans-Achim

    2015-06-08

    The C-nucleoside based on the hydroxyquinoline ligand (Hq) is complementary to itself and forms stable Hq-Hq pairs in double-stranded DNA. These artificial Hq-Hq pairs may serve as artificial electron carriers for long-range photoinduced electron transfer in DNA, as elucidated by a combination of gel electrophoretic analysis of irradiated samples and time-resolved transient absorption spectroscopy. For this study, the Hq-Hq pair was combined with a DNA-based donor-acceptor system consisting of 6-N,N-dimethylaminopyrene conjugated to 2'-deoxyuridine as photoinducible electron donor, and methyl viologen attached to the 2'-position of uridine as electron acceptor. The Hq radical anion was identified in the time-resolved measurements and strand cleavage products support its role as an intermediate charge carrier. Hence, the Hq-Hq pair significantly enhances the electron hopping capability of DNA compared to natural DNA bases over long distances while keeping the self-assembly properties as the most attractive feature of DNA as a supramolecular architecture. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. UV-resistant Acinetobacter sp. isolates from Andean wetlands display high catalase activity.

    Science.gov (United States)

    Di Capua, Cecilia; Bortolotti, Ana; Farías, María Eugenia; Cortez, Néstor

    2011-04-01

    Andean wetlands are characterized by their extreme environmental conditions such as high UV radiation, elevated heavy metal content and salinity. We present here the first study on UV tolerance and antioxidant defense of four Acinetobacter strains: Ver3, Ver5 and Ver7, isolated from Lake Verde, and N40 from Lake Negra, both lakes located 4400 m above sea level. All four isolates displayed higher UV resistance compared with collection strains, with Ver3 and Ver7 being the most tolerant strains not only to UV radiation but also to hydrogen peroxide (H(2)O(2)) and methyl viologen (MV) challenges. A single superoxide dismutase band with similar activity was detected in all studied strains, whereas different electrophoretic pattern and activity levels were observed for catalase. Ver3 and Ver7 displayed 5-15 times higher catalase activity levels than the control strains. Analysis of the response of antioxidant enzymes to UV and oxidative challenges revealed a significant increase in Ver7 catalase activity after H(2)O(2) and MV exposure. Incubation of Ver7 cultures with a catalase inhibitor resulted in a significant decrease of tolerance against UV radiation. We conclude that the high catalase activity displayed by Ver7 isolate could play an important role in UV tolerance. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  5. Choline oxidation by intact spinach chloroplasts. [Spinacia oleracea L

    Energy Technology Data Exchange (ETDEWEB)

    Weigel, P.; Lerma, C.; Hanson, A.D.

    1988-01-01

    Plants synthesize betaine by a two-step oxidation of choline (choline ..-->.. betaine aldehyde ..-->.. betaine). Protoplast-derived chloroplasts of spinach (Spinacia oleracea L.) carry out both reactions, more rapidly in light than in darkness. We investigated the light-stimulated oxidation of choline, using spinach chloroplasts isolated directly from leaves. The rates of choline oxidation obtained (dark and light rates: 10-50 and 100-300 nanomoles per hour per milligram chlorophyll, respectively) were approximately 20-fold higher than for protoplast-derived chloroplasts. Betaine aldehyde was the main product. Choline oxidation in darkness and light was suppressed by hypoxia. Neither uncouplers not the Calvin cycle inhibitor glyceraldehyde greatly affected choline oxidation in the light, and maximal choline oxidation was attained far below light saturation of CO/sub 2/ fixation. The light stimulation of choline oxidation was abolished by the PSII inhibitors DCMU and dibromothymoquinone, and was partially restored by adding reduced diaminodurene, an electron donor to PSI. Both methyl viologen and phenazine methosulfate prevented choline oxidation. Adding dihydroxyacetone phosphate, which can generate NADPH in organello, doubled the dark rate of choline oxidation. These results indicate that choline oxidation in chloroplasts requires oxygen, and reducing power generated from PSI. Enzymic reactions consistent with these requirements are discussed.

  6. A novel versatile microbiosensor for local hydrogen detection by means of scanning photoelectrochemical microscopy.

    Science.gov (United States)

    Zhao, Fangyuan; Conzuelo, Felipe; Hartmann, Volker; Li, Huaiguang; Stapf, Stefanie; Nowaczyk, Marc M; Rögner, Matthias; Plumeré, Nicolas; Lubitz, Wolfgang; Schuhmann, Wolfgang

    2017-08-15

    The development of a versatile microbiosensor for hydrogen detection is reported. Carbon-based microelectrodes were modified with a [NiFe]-hydrogenase embedded in a viologen-modified redox hydrogel for the fabrication of a sensitive hydrogen biosensor By integrating the microbiosensor in a scanning photoelectrochemical microscope, it was capable of serving simultaneously as local light source to initiate photo(bio)electrochemical reactions while acting as sensitive biosensor for the detection of hydrogen. A hydrogen evolution biocatalyst based on photosystem 1-platinum nanoparticle biocomplexes embedded into a specifically designed redox polymer was used as a model for proving the capability of the developed hydrogen biosensor for the detection of hydrogen upon localized illumination. The versatility and sensitivity of the proposed microbiosensor as probe tip allows simplification of the set-up used for the evaluation of complex electrochemical processes and the rapid investigation of local photoelectrocatalytic activity of biocatalysts towards light-induced hydrogen evolution. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. The microalga Chlamydomonas reinhardtii CW-15 as a solar cell for hydrogen peroxide photoproduction. Comparison between free and immobilized cells and thylakoids for energy conversion efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, W.; Galvan, F.; Rosa, F.F. de la [Instituto de Bioquimica Vegetal y Fotosintesis, Universidad de Sevilla y CSIC, Sevilla (Spain)

    1995-11-28

    Immobilized cells and thylakoid vesicles of the microalga Chlamydomonas reinhardtii CW-15 have been developed as a solar cell because of their capabilities of producing hydrogen peroxide. This compound is an efficient and clean fuel used for rocket propulsion, motors and for heating. Hydrogen peroxide is produced by the photosystem in a catalyst cycle in which a redox mediator (methyl viologen) is reduced by electrons obtained from water by the photosynthetic apparatus of the microalga and it is re-oxidized by the oxygen dissolved in the solution. The photoproduction has been investigated using a discontinuous system with whole cells, or thylakoid vesicles, free or immobilized on alginate. The stimulation by azide as an inhibitor of catalase has also been analyzed. Under determined optimum conditions, the photoproduction by Ca-alginate entrapped cells, with a rate of 33 {mu}mol H{sub 2}O{sub 2}/mg Chl.h, was maintained for several hours with an energy conversion efficiency of 0.25%

  8. Molecular pop-up toy: a molecular machine based on folding/unfolding motion of alkyl chains bound to a host.

    Science.gov (United States)

    Ko, Young Ho; Hwang, Ilha; Kim, Hyunuk; Kim, Youngkook; Kim, Kimoon

    2015-01-01

    We have designed and synthesized a new type of molecular machine based on the folding/unfolding motion of an alkyl chain bound to a host, triggered by a redox stimulus. A guest molecule containing a viologen unit with a long alkyl chain 1(2+) and its one-electron reduced species 1 + . form very stable 1:1 host-guest complexes 2(2+) and 2 + ., respectively, with cucurbit[8]uril (CB[8]), where the long alkyl chain of the guests is in a folded conformation inside the host cavity. Upon addition of 2,6-dihydroxynaphthalene as an electron donor, the binary complex 2(2+) turns into a ternary complex 3(2+) through host-stabilized charge-transfer complex formation with the alkyl chain extended into the solution outside the host cavity. The ternary complex behaves like a molecular machine reminiscent of a pop-up toy, as it shows reversible folding/unfolding motion of the alkyl chain of the guest in response to a redox stimulus. For example, one-electron reduction of 3(2+) results in the rapid generation of the 2 + . complex, accompanied by a dramatic conformational change of the alkyl chain from an extended to a folded conformation, and the process can be reversed by oxidation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Immobilization of hydrogenase on carbon nanotube polyelectrolytes as heterogeneous catalysts for electrocatalytic interconversion of protons and hydrogen

    Science.gov (United States)

    Liu, Jiang; Wu, Wen-Jie; Fang, Fang; Zorin, Nikolay A.; Chen, Meng; Qian, Dong-Jin

    2016-08-01

    Immobilization of active enzymes on the surfaces of electrodes and nanomaterials is important in the fields of bioscience, and biotechnology. In this study, we investigated electrocatalytic properties of the interconversion of protons and hydrogen by means of hydrogenase (H2ase)-functionalized carbon nanotube polyelectrolyte composites. Multiwalled carbon nanotube polyelectrolytes (MWNT-PEs) were synthesized through a diazonium and an addition reaction with poly(4-vinylpyridine) (P4VP), followed by another addition reaction with either methyl iodide (CH3I) or N-methyl- N'-benzyl bromide bipyridinium (VBenBr) to produce MWNT-P4VPMe or MWNT-P4VPBenV polyelectrolytes, respectively. The MWNT-PE@H2ase bio-nanocomposites were then prepared by means of MWNT-PEs as substrates to bind with H2ase. The redox current density of the MWNT-PE@H2ase-modified electrodes increased with a decrease in pH values of the Ar-saturated electrolyte solution owing to the catalytic reduction of protons (H2 production); further, it increased with the increasing pH values of the H2-saturated solution owing to the catalytic oxidation of hydrogen. The reversible color change between blue-colored and colorless viologen (catalyzed by the MWNT-PE@H2ase bio-nanocomposites) suggested that they may be developed as nano-biosensors for molecular H2. The as-synthesized bio-nanocomposites showed strong long-term stability and high bioactivity.

  10. Interconversion between formate and hydrogen carbonate by tungsten-containing formate dehydrogenase-catalyzed mediated bioelectrocatalysis

    Directory of Open Access Journals (Sweden)

    Kento Sakai

    2015-09-01

    Full Text Available We have focused on the catalytic properties of tungsten-containing formate dehydrogenase (FoDH1 from Methylobacterium extorquens AM1 to construct a bioelectrochemical interconversion system between formate (HCOO− and hydrogen carbonate (HCO3−. FoDH1 catalyzes both of the HCOO oxidation and the HCO3− reduction with several artificial dyes. The bi-molecular reaction rate constants between FoDH1 and the artificial electron acceptors and NAD+ (as the natural electron acceptor show the property called a linear free energy relationship (LFER, indicating that FoDH1 would have no specificity to NAD+. Similar LFER is also observed for the catalytic reduction of HCO3−. The reversible reaction between HCOO− and HCO3− through FoDH1 has been realized on cyclic voltammetry by using methyl viologen (MV as a mediator and by adjusting pH from the thermodynamic viewpoint. Potentiometric measurements have revealed that the three redox couples, MV2+/MV·−+, HCOO−/HCO3−, FoDH1 (ox/red, reach an equilibrium in the bulk solution when the two-way bioelectrocatalysis proceeds in the presence of FoDH1 and MV. The steady-state voltammograms with two-way bioelectrocatalytic properties are interpreted on a simple model by considering the solution equilibrium.

  11. MSRB7 reverses oxidation of GSTF2/3 to confer tolerance of Arabidopsis thaliana to oxidative stress

    Science.gov (United States)

    Lee, Shu-Hong; Li, Chia-Wen; Koh, Kah Wee; Chuang, Hsin-Yu; Chen, Yet-Ran; Lin, Choun-Sea; Chan, Ming-Tsair

    2014-01-01

    Methionine sulfoxide reductases (MSRs) catalyse the reduction of oxidized methionine residues, thereby protecting proteins against oxidative stress. Accordingly, MSRs have been associated with stress responses, disease, and senescence in a taxonomically diverse array of organisms. However, the cytosolic substrates of MSRs in plants remain largely unknown. Here, we used a proteomic analysis strategy to identify MSRB7 substrates. We showed that two glutathione transferases (GSTs), GSTF2 and GSTF3, had fewer oxidized methionine (MetO) residues in MSRB7-overexpressing Arabidopsis thaliana plants than in wild-type plants. Conversely, GSTF2 and GSTF3 were highly oxidized and unstable in MSRB7-knockdown plants. MSRB7 was able to restore the MetO-GSTF2M100/104 and MetO-GSTF3M100 residues produced during oxidative stress. Furthermore, both GSTs were specifically induced by the oxidative stress inducer, methyl viologen. Our results indicate that specific GSTs are substrates of MSRs, which together provide a major line of defence against oxidative stress in A. thaliana. PMID:24962998

  12. Overexpression of a tobacco small G protein gene NtRop1 causes salt sensitivity and hydrogen peroxide production in transgenic plants.

    Science.gov (United States)

    Cao, YangRong; Li, ZhiGang; Chen, Tao; Zhang, ZhiGang; Zhang, JinSong; Chen, ShouYi

    2008-05-01

    The small GTPases of Rop/Rho family is central regulators of important cellular processes in plants. Tobacco small G protein gene NtRop1 has been isolated; however, its roles in stress responses were unknown. In the present study, the genomic sequence of NtRop1 was cloned, which has seven exons and six introns, similar to the Rop gene structure from Arabidopsis. The NtRop1 gene was constitutively expressed in the different organs whereas the other six Rop genes from tobacco had differential expression patterns. The expression of the NtRop1 gene was moderately induced by methyl viologen, NaCl, and ACC treatments, but slightly inhibited by ABA treatment, with no significant induction by NAA treatment. The transgenic Arabidopsis plants overexpressing the NtRop1 showed increased salt sensitivity as can be seen from the reduced root growth and elevated relative electrolyte leakage. The hydrogen peroxide production was also promoted in the NtRop1-trangenic plants in comparison with wild type plants. These results imply that the NtRop1 may confer salt sensitivity through activation of H2O2 production during plant response to salt stress.

  13. Evidence for chloroplastic succinate dehydrogenase participating in the chloroplastic respiratory and photosynthetic electron transport chains of Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Willeford, K.O.; Gombos, Z.; Gibbs, M. (Brandeis Univ., Waltham, MA (USA))

    1989-07-01

    A method for isolating intact chloroplasts from Chlamydomonas reinhardtii F-60 was developed from the Klein, Chen, Gibbs, Platt-Aloia procedure. Protoplasts, generated by treatment with autolysine, were lysed with a solution of digitonin and fractionated on Percoll step gradients. The chloroplasts were assessed to be 90% intact (ferricyanide assay) and free from cytoplasmic contamination (NADP isocitrate dehydrogenase activity) and to range from 2 to 5% in mitochondrial contamination (cytochrome c oxidase activity). About 25% of the cellular succinate dehydrogenase activity (21.6 micromoles per milligram chlorophyll per hour, as determined enzymically) was placed within the chloroplast. Chloroplastic succinate dehydrogenase had a K{sub m} for succinate of 0.55 millimolar and was associated with the thylakoidal material derived from the intact chloroplasts. This same thylakoidal material, with an enzymic assay of 21.6 micromoles per milligram chlorophyll per hour was able to initiate a light-dependent uptake of oxygen at a rate of 16.4 micromoles per milligram chlorophyll per hour when supplied with succinate and methyl viologen. Malonate was an apparent competitive inhibitor of this reaction. The succinate dehydrogenase activity present in the chloroplast was sufficient to account for the photoanaerobic rate of acetate dissimilation in H{sub 2} adapted Chlamydomonas.

  14. Expression of a rice glutaredoxin in aleurone layers of developing and mature seeds: subcellular localization and possible functions in antioxidant defense.

    Science.gov (United States)

    Morita, Shigeto; Yamashita, Yuki; Fujiki, Masayoshi; Todaka, Rie; Nishikawa, Yuri; Hosoki, Ayaka; Yabe, Chisato; Nakamura, Jun'ichi; Kawamura, Kazuyoshi; Suwastika, I Nengah; Sato, Masa H; Masumura, Takehiro; Ogihara, Yasunari; Tanaka, Kunisuke; Satoh, Shigeru

    2015-11-01

    A rice glutaredoxin isoform (OsGrxC2;2) with antioxidant capacity is expressed abundantly in seed tissues and is localized to storage vacuoles in aleurone layers in developing and mature seeds. Seed tissues undergo drastic water loss at the late stage of seed development, and thus need to tolerate oxidative injuries associated with desiccation. We previously found a rice glutaredoxin isoform, OsGrxC2;2, as a gene expressed abundantly in developing seeds. Since glutaredoxin is involved in antioxidant defense, in the present study we investigated the subcellular localization and expression profile of OsGrxC2;2 and whether OsGrxC2;2 has a role in the defense against reactive oxygen species. Western blotting and immunohistochemistry revealed that the OsGrxC2;2 protein accumulated at a high level in the embryo and aleurone layers of developing and mature seeds. The OsGrxC2;2 in developing seeds was particularly localized to aleurone grains, which are storage organelles derived from vacuoles. Overexpression of OsGrxC2;2 resulted in an enhanced tolerance to menadione in yeast and methyl viologen in green leaves of transgenic rice plants. These results suggest that OsGrxC2;2 participates in the defense against oxidative stress in developing and mature seeds.

  15. Transgenic poplar expressing Arabidopsis NDPK2 enhances growth as well as oxidative stress tolerance.

    Science.gov (United States)

    Kim, Yun-Hee; Kim, Myoung Duck; Choi, Young Im; Park, Sung-Chul; Yun, Dae-Jin; Noh, Eun Woon; Lee, Haeng-Soon; Kwak, Sang-Soo

    2011-04-01

    Nucleoside diphosphate kinase 2 (NDPK2) is known to regulate the expression of antioxidant genes in plants. Previously, we reported that overexpression of Arabidopsis NDPK2 (AtNDPK2) under the control of an oxidative stress-inducible SWPA2 promoter in transgenic potato and sweetpotato plants enhanced tolerance to various abiotic stresses. In this study, transgenic poplar (Populus alba × Poplus glandulosa) expressing the AtNDPK2 gene under the control of a SWPA2 promoter (referred to as SN) was generated to develop plants with enhanced tolerance to oxidative stress. The level of AtNDPK2 expression and NDPK activity in SN plants following methyl viologen (MV) treatment was positively correlated with the plant's tolerance to MV-mediated oxidative stress. We also observed that antioxidant enzyme activities such as ascorbate peroxidase, catalase and peroxidase were increased in MV-treated leaf discs of SN plants. The growth of SN plants was substantially increased under field conditions including increased branch number and stem diameter. SN plants exhibited higher transcript levels of the auxin-response genes IAA2 and IAA5. These results suggest that enhanced AtNDPK2 expression affects oxidative stress tolerance leading to improved plant growth in transgenic poplar. © 2010 The Authors. Plant Biotechnology Journal © 2010 Society for Experimental Biology, Association of Applied Biologists and Blackwell Publishing Ltd.

  16. Enhancement of oxidative and drought tolerance in Arabidopsis by overaccumulation of antioxidant flavonoids

    Science.gov (United States)

    Nakabayashi, Ryo; Yonekura-Sakakibara, Keiko; Urano, Kaoru; Suzuki, Makoto; Yamada, Yutaka; Nishizawa, Tomoko; Matsuda, Fumio; Kojima, Mikiko; Sakakibara, Hitoshi; Shinozaki, Kazuo; Michael, Anthony J; Tohge, Takayuki; Yamazaki, Mami; Saito, Kazuki

    2014-01-01

    The notion that plants use specialized metabolism to protect against environmental stresses needs to be experimentally proven by addressing the question of whether stress tolerance by specialized metabolism is directly due to metabolites such as flavonoids. We report that flavonoids with radical scavenging activity mitigate against oxidative and drought stress in Arabidopsis thaliana. Metabolome and transcriptome profiling and experiments with oxidative and drought stress in wild-type, single overexpressors of MYB12/PFG1 (PRODUCTION OF FLAVONOL GLYCOSIDES1) or MYB75/PAP1 (PRODUCTION OF ANTHOCYANIN PIGMENT1), double overexpressors of MYB12 and PAP1, transparent testa4 (tt4) as a flavonoid-deficient mutant, and flavonoid-deficient MYB12 or PAP1 overexpressing lines (obtained by crossing tt4 and the individual MYB overexpressor) demonstrated that flavonoid overaccumulation was key to enhanced tolerance to such stresses. Antioxidative activity assays using 2,2-diphenyl-1-picrylhydrazyl, methyl viologen, and 3,3′-diaminobenzidine clearly showed that anthocyanin overaccumulation with strong in vitro antioxidative activity mitigated the accumulation of reactive oxygen species in vivo under oxidative and drought stress. These data confirm the usefulness of flavonoids for enhancing both biotic and abiotic stress tolerance in crops. PMID:24274116

  17. The Performance of Electron-Mediator Modified Activated Carbon as Anode for Direct Glucose Alkaline Fuel Cell

    Directory of Open Access Journals (Sweden)

    Zi Li

    2016-06-01

    Full Text Available Six different electron mediators were immobilized on the activated carbon (AC anode and their effects on performance of a direct glucose alkaline fuel cell were explored. 2-hydroxy-1, 4-naphthoquinone (NQ, methyl viologen (MV, neutral red (NR, methylene blue (MB, 1, 5-dichloroanthraquinone (DA and anthraquinone (AQ were doped in activated carbon (AC, respectively, and pressed on nickel foam to fabricate the anodes. NQ shows comparable performance with MV, but with much lower cost and environmental impact. With NQ-AC anode, the fuel cell attained a peak power density of 16.10 Wm−2, peak current density of 48.09 Am−2, and open circuit voltage of 0.76 V under the condition of 1 M glucose, 3 M KOH, and ambient temperature. Polarization curve, EIS and Tafel measurements were also conducted to explore the mechanism of performance enhancement. The high performance is likely due to the enhanced charge transfer and more reactive sites provided on the anode.

  18. Fermentation and genomic analysis of acetone-uncoupled butanol production by Clostridium tetanomorphum.

    Science.gov (United States)

    Gong, Fuyu; Bao, Guanhui; Zhao, Chunhua; Zhang, Yanping; Li, Yin; Dong, Hongjun

    2016-02-01

    In typical acetone-butanol-ethanol (ABE) fermentation, acetone is the main by-product (50 % of butanol mass) of butanol production, resulting in a low yield of butanol. It is known that some Clostridium tetanomorphum strains are able to produce butanol without acetone in nature. Here, we described that C. tetanomorphum strain DSM665 can produce 4.16 g/L butanol and 4.98 g/L ethanol at pH 6.0, and 9.81 g/L butanol and 1.01 g/L ethanol when adding 1 mM methyl viologen. Butyrate and acetate could be reassimilated and no acetone was produced. Further analysis indicated that the activity of the acetate/butyrate:acetoacetyl-CoA transferase responsible for acetone production is lost in C. tetanomorphum DSM665. The genome of C. tetanomorphum DSM665 was sequenced and deposited in DDBJ, EMBL, and GenBank under the accession no. APJS00000000. Sequence analysis indicated that there are no typical genes (ctfA/B and adc) that are typically parts of an acetone synthesis pathway in C. tetanomorphum DSM665. This work provides new insights in the mechanism of clostridial butanol production and should prove useful for the design of a high-butanol-producing strain.

  19. Confocal absorption spectral imaging of MoS2: optical transitions depending on the atomic thickness of intrinsic and chemically doped MoS2.

    Science.gov (United States)

    Dhakal, Krishna P; Duong, Dinh Loc; Lee, Jubok; Nam, Honggi; Kim, Minsu; Kan, Min; Lee, Young Hee; Kim, Jeongyong

    2014-11-07

    We performed a nanoscale confocal absorption spectral imaging to obtain the full absorption spectra (over the range 1.5-3.2 eV) within regions having different numbers of layers and studied the variation of optical transition depending on the atomic thickness of the MoS2 film. Three distinct absorption bands corresponding to A and B excitons and a high-energy background (BG) peak at 2.84 eV displayed a gradual redshift as the MoS2 film thickness increased from the monolayer, to the bilayer, to the bulk MoS2 and this shift was attributed to the reduction of the gap energy in the Brillouin zone at the K-point as the atomic thickness increased. We also performed n-type chemical doping of MoS2 films using reduced benzyl viologen (BV) and the confocal absorption spectra modified by the doping showed a strong dependence on the atomic thickness: A and B exciton peaks were greatly quenched in the monolayer MoS2 while much less effect was shown in larger thickness and the BG peak either showed very small quenching for 1 L MoS2 or remained constant for larger thicknesses. Our results indicate that confocal absorption spectral imaging can provide comprehensive information on optical transitions of microscopic size intrinsic and doped two-dimensional layered materials.

  20. Allosteric indicator displacement enzyme assay for a cyanogenic glycoside.

    Science.gov (United States)

    Jose, D Amilan; Elstner, Martin; Schiller, Alexander

    2013-10-18

    Indicator displacement assays (IDAs) represent an elegant approach in supramolecular analytical chemistry. Herein, we report a chemical biosensor for the selective detection of the cyanogenic glycoside amygdalin in aqueous solution. The hybrid sensor consists of the enzyme β-glucosidase and a boronic acid appended viologen together with a fluorescent reporter dye. β-Glucosidase degrades the cyanogenic glycoside amygdalin into hydrogen cyanide, glucose, and benzaldehyde. Only the released cyanide binds at the allosteric site of the receptor (boronic acid) thereby inducing changes in the affinity of a formerly bound fluorescent indicator dye at the other side of the receptor. Thus, the sensing probe performs as allosteric indicator displacement assay (AIDA) for cyanide in water. Interference studies with inorganic anions and glucose revealed that cyanide is solely responsible for the change in the fluorescent signal. DFT calculations on a model compound revealed a 1:1 binding ratio of the boronic acid and cyanide ion. The fluorescent enzyme assay for β-glucosidase uses amygdalin as natural substrate and allows measuring Michaelis-Menten kinetics in microtiter plates. The allosteric indicator displacement assay (AIDA) probe can also be used to detect cyanide traces in commercial amygdalin samples. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. A ZnO nanowire bio-hybrid solar cell

    Science.gov (United States)

    Yaghoubi, Houman; Schaefer, Michael; Yaghoubi, Shayan; Jun, Daniel; Schlaf, Rudy; Beatty, J. Thomas; Takshi, Arash

    2017-02-01

    Harvesting solar energy as a carbon free source can be a promising solution to the energy crisis and environmental pollution. Biophotovoltaics seek to mimic photosynthesis to harvest solar energy and to take advantage of the low material costs, negative carbon footprint, and material abundance. In the current study, we report on a combination of zinc oxide (ZnO) nanowires with monolayers of photosynthetic reaction centers which are self-assembled, via a cytochrome c linker, as photoactive electrode. In a three-probe biophotovoltaics cell, a photocurrent density of 5.5 μA cm-2 and photovoltage of 36 mV was achieved, using methyl viologen as a redox mediator in the electrolyte. Using ferrocene as a redox mediator a transient photocurrent density of 8.0 μA cm-2 was obtained, which stabilized at 6.4 μA cm-2 after 20 s. In-depth electronic structure characterization using photoemission spectroscopy in conjunction with electrochemical analysis suggests that the fabricated photoactive electrode can provide a proper electronic path for electron transport all the way from the conduction band of the ZnO nanowires, through the protein linker to the RC, and ultimately via redox mediator to the counter electrode.

  2. Oxidation resistance 1 is essential for protection against oxidative stress and participates in the regulation of aging in Caenorhabditis elegans.

    Science.gov (United States)

    Sanada, Y; Asai, S; Ikemoto, A; Moriwaki, T; Nakamura, N; Miyaji, M; Zhang-Akiyama, Q-M

    2014-08-01

    Human oxidation resistance 1 (OXR1) functions in protection against oxidative damage and its homologs are highly conserved in eukaryotes examined so far, but its function still remains uncertain. In this study, we identified a homolog (LMD-3) of human OXR1 in the nematode Caenorhabditis elegans (C. elegans). The expressed LMD-3 was able to suppress the mutator phenotypes of E. coli mutMmutY and mutT mutants. Purified LMD-3 did not have enzymatic activity against 8-oxoG, superoxide dismutase (SOD), or catalase activities. Interestingly, the expression of LMD-3 was able to suppress the methyl viologen or menadione sodium bisulfite-induced expression of soxS and sodA genes in E. coli. The sensitivity of the C. elegans lmd-3 mutant to oxidative and heat stress was markedly higher than that of the wild-type strain N2. These results suggest that LMD-3 protects cells against oxidative stress. Furthermore, we found that the lifespan of the C. elegans lmd-3 mutant was significantly reduced compared with that of the N2, which was resulted from the acceleration of aging. We further examined the effects of deletions in other oxidative defense genes on the properties of the lmd-3 mutant. The deletion of sod-2 and sod-3, which are mitochondrial SODs, extended the lifespan of the lmd-3 mutant. These results indicate that, in cooperation with mitochondrial SODs, LMD-3 contributes to the protection against oxidative stress and aging in C. elegans.

  3. Ultrafast response humidity sensor using supramolecular nanofibre and its application in monitoring breath humidity and flow.

    Science.gov (United States)

    Mogera, Umesha; Sagade, Abhay A; George, Subi J; Kulkarni, Giridhar U

    2014-02-17

    Measuring humidity in dynamic situations calls for highly sensitive fast response sensors. Here we report, a humidity sensor fabricated using solution processed supramolecular nanofibres as active resistive sensing material. The nanofibres are built via self- assembly of donor and acceptor molecules (coronene tetracarboxylate and dodecyl methyl viologen respectively) involved in charge transfer interactions. The conductivity of the nanofibre varied sensitively over a wide range of relative humidity (RH) with unprecedented fast response and recovery times. Based on UV-vis, XRD and AFM measurements, it is found that the stacking distance in the nanofibre decreases slightly while the charge transfer band intensity increases, all observations implying enhanced charge transfer interaction and hence the conductivity. It is demonstrated to be as a novel breath sensor which can monitor the respiration rate. Using two humidity sensors, a breath flow sensor was made which could simultaneously measure RH and flow rate of exhaled nasal breath. The integrated device was used for monitoring RH in the exhaled breath from volunteers undergoing exercise and alcohol induced dehydration.

  4. A Rice Immunophilin Gene, OsFKBP16-3, Confers Tolerance to Environmental Stress in Arabidopsis and Rice

    Directory of Open Access Journals (Sweden)

    Jun Cheul Ahn

    2013-03-01

    Full Text Available The putative thylakoid lumen immunophilin, FKBP16-3, has not yet been characterized, although this protein is known to be regulated by thioredoxin and possesses a well-conserved CxxxC motif in photosynthetic organisms. Here, we characterized rice OsFKBP16-3 and examined the role of this gene in the regulation of abiotic stress in plants. FKBP16-3s are well conserved in eukaryotic photosynthetic organisms, including the presence of a unique disulfide-forming CxxxC motif in their N-terminal regions. OsFKBP16-3 was mainly expressed in rice leaf tissues and was upregulated by various abiotic stresses, including salt, drought, high light, hydrogen peroxide, heat and methyl viologen. The chloroplast localization of OsFKBP16-3-GFP was confirmed through the transient expression of OsFKBP16-3 in Nicotiana benthamiana leaves. Transgenic Arabidopsis and transgenic rice plants that constitutively expressed OsFKBP16-3 exhibited increased tolerance to salinity, drought and oxidative stresses, but showed no change in growth or phenotype, compared with vector control plants, when grown under non-stressed conditions. This is the first report to demonstrate the potential role of FKBP16-3 in the environmental stress response, which may be regulated by a redox relay process in the thylakoid lumen, suggesting that artificial regulation of FKBP16-3 expression is a candidate for stress-tolerant crop breeding.

  5. An Aqueous Redox-Flow Battery with High Capacity and Power: The TEMPTMA/MV System.

    Science.gov (United States)

    Janoschka, Tobias; Martin, Norbert; Hager, Martin D; Schubert, Ulrich S

    2016-11-07

    Redox-flow batteries (RFB) can easily store large amounts of electric energy and thereby mitigate the fluctuating output of renewable power plants. They are widely discussed as energy-storage solutions for wind and solar farms to improve the stability of the electrical grid. Most common RFB concepts are based on strongly acidic metal-salt solutions or poorly performing organics. Herein we present a battery which employs the highly soluble N,N,N-2,2,6,6-heptamethylpiperidinyl oxy-4-ammonium chloride (TEMPTMA) and the viologen derivative N,N'-dimethyl-4,4-bipyridinium dichloride (MV) in a simple and safe aqueous solution as redox-active materials. The resulting battery using these electrolyte solutions has capacities of 54 Ah L-1 , giving a total energy density of 38 Wh L-1 at a cell voltage of 1.4 V. With peak current densities of up to 200 mA cm-2 the TEMPTMA/MV system is a suitable candidate for compact high-capacity and high-power applications. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Designed Surface Residue Substitutions in [NiFe] Hydrogenase that Improve Electron Transfer Characteristics

    Directory of Open Access Journals (Sweden)

    Isaac T. Yonemoto

    2015-01-01

    Full Text Available Photobiological hydrogen production is an attractive, carbon-neutral means to convert solar energy to hydrogen. We build on previous research improving the Alteromonas macleodii “Deep Ecotype” [NiFe] hydrogenase, and report progress towards creating an artificial electron transfer pathway to supply the hydrogenase with electrons necessary for hydrogen production. Ferredoxin is the first soluble electron transfer mediator to receive high-energy electrons from photosystem I, and bears an electron with sufficient potential to efficiently reduce protons. Thus, we engineered a hydrogenase-ferredoxin fusion that also contained several other modifications. In addition to the C-terminal ferredoxin fusion, we truncated the C-terminus of the hydrogenase small subunit, identified as the available terminus closer to the electron transfer region. We also neutralized an anionic patch surrounding the interface Fe-S cluster to improve transfer kinetics with the negatively charged ferredoxin. Initial screening showed the enzyme tolerated both truncation and charge neutralization on the small subunit ferredoxin-binding face. While the enzyme activity was relatively unchanged using the substrate methyl viologen, we observed a marked improvement from both the ferredoxin fusion and surface modification using only dithionite as an electron donor. Combining ferredoxin fusion and surface charge modification showed progressively improved activity in an in vitro assay with purified enzyme.

  7. Boronic acid recognition of non-interacting carbohydrates for biomedical applications: increasing fluorescence signals of minimally interacting aldoses and sucralose.

    Science.gov (United States)

    Resendez, Angel; Halim, Md Abdul; Singh, Jasmeet; Webb, Dominic-Luc; Singaram, Bakthan

    2017-11-22

    To address carbohydrates that are commonly used in biomedical applications with low binding affinities for boronic acid based detection systems, two chemical modification methods were utilized to increase sensitivity. Modified carbohydrates were analyzed using a two component fluorescent probe based on boronic acid-appended viologen-HPTS (4,4'-o-BBV). Carbohydrates normally giving poor signals (fucose, l-rhamnose, xylose) were subjected to sodium borohydride (NaBH 4 ) reduction in ambient conditions for 1 h yielding the corresponding sugar alcohols from fucose, l-rhamnose and xylose in essentially quantitative yields. Compared to original aldoses, apparent binding affinities were increased 4-25-fold. The chlorinated sweetener and colon permeability marker sucralose (Splenda), otherwise undetectable by boronic acids, was dechlorinated to a detectable derivative by reactive oxygen and hydroxide intermediates by the Fenton reaction or by H 2 O 2 and UV light. This method is specific to sucralose as other common sugars, such as sucrose, do not contain any carbon-chlorine bonds. Significant fluorescence response was obtained for chemically modified sucralose with the 4,4'-o-BBV-HPTS probe system. This proof of principle can be applied to biomedical applications, such as gut permeability, malabsorption, etc.

  8. Occurrence and localization of two distinct hydrogenases in the heterocystous cyanobacterium Anabaena sp. strain 7120.

    Science.gov (United States)

    Houchins, J P; Burris, R H

    1981-04-01

    Two distinct types of hydrogenase occur in Anabaena 7120 and are distinguishable in whole filaments by the application of selective assay methods. A reversible hydrogenase occurs both in heterocysts and vegetative cells and can be selectively assayed by measuring H2 evolution from reduced methyl viologen. Activities in aerobically grown filaments were low but could be increased by 2 to 3 orders of magnitude by growing cells microaerobically. The presence of the reversible hydrogenase was independent of the N2-fixing properties of the organism, and activity did not respond to added H2 in the culture. Illumination was necessary during derepression of the reversible hydrogenase, and addition of 3-(3',4'-dichlorophenyl)-1,1-dimethylurea increased the amount of enzyme that was synthesized. An uptake hydrogenase occurred only in heterocysts of aerobically grown filaments, but a small amount of activity also was present in the vegetative cells of filaments grown microaerobically with 20% H2. It was assayed selectively by measuring an oxyhydrogen reaction at atmospheric levels of O2. Additional uptake hydrogenase could be elicited by including H2 or by removing O2 from the sparging gas of a culture.

  9. Hydrogenase-Mediated Activities in Isolated Chloroplasts of Chlamydomonas reinhardii1

    Science.gov (United States)

    Maione, Theodore E.; Gibbs, Martin

    1986-01-01

    Isolated intact chloroplasts of Chlamydomonas reinhardii were found to catalyze photoreduction of CO2 in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea when adapted under an atmosphere of H2 demonstrating the association of a hydrogenase and anaerobic adaptation system with these plastids. The specific activity of photoreduction was approximately one third that detected in cells and protoplasts. Photoreduction was found to have a lower osmoticum optimum relative to aerobically maintained chloroplasts (50 millimolar versus 120 millimolar mannitol). 3-Phosphoglycerate (3-PGA) stimulated photoreduction up to a peak at 0.25 millimolar beyond which inhibition was observed. In the absence of 3-PGA, inorganic phosphate had no effect on photoreduction but in the presence of 3-PGA, inorganic phosphate also stimulated the reaction. Carbonyl cyanide-p-trifluoromethoxyphenylhydrazone and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone inhibited photoreduction but inhibition by the former could be partially overcome by exogenously added ATP. The intact plastid can also catalyze photoevolution of H2 while lysed chloroplast extracts catalyzed the reduction of methyl viologen by H2. Both reactions occurred at rates approximately one-third of those found in cells. The oxyhydrogen reaction in the presence or absence of CO2 was not detected. PMID:16664626

  10. Aerobic hydrogenase activity in Anacystis nidulans. The oxyhydrogen reaction.

    Science.gov (United States)

    Peschek, G A

    1979-11-08

    1. The oxyhydrogen reaction of Anacystis nidulans was studied manometrically and polarographically in whole cells and in cell-free preparations; the activity was found to be associated with the particulate fraction. 2. Besides O2, the isolated membranes reduced artificial electron acceptors of positive redox potential; the reactions were unaffected by O2 levels less than 10--15%; aerobically the artificial acceptors were reduced simultaneously with O2. 3. H2-supported O2 uptake was inhibited by CO, KCN and 2-n-heptyl-8-hydroxyquinoline-N-oxide. Inhibition by CO was partly reversed by strong light. Uncouplers stimulated the oxyhydrogen reaction. 4. The kinetic properties of O2 uptake by isolated membranes were the same in presence of H2 and of other respiratory substrates. 5. Low rates of H2 evolution by the membrane preparations were found in presence of dithionite; methyl viologen stimulated the reaction. 6. The results indicate that under certain growth conditions Anacystis synthesizes a membrane-bound hydrogenase which appears to be involved in phosphorylative electron flow from H2 to O2 through the respiratory chain.

  11. Hydrogenase-Mediated Activities in Isolated Chloroplasts of Chlamydomonas reinhardii.

    Science.gov (United States)

    Maione, T E; Gibbs, M

    1986-02-01

    Isolated intact chloroplasts of Chlamydomonas reinhardii were found to catalyze photoreduction of CO(2) in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea when adapted under an atmosphere of H(2) demonstrating the association of a hydrogenase and anaerobic adaptation system with these plastids. The specific activity of photoreduction was approximately one third that detected in cells and protoplasts. Photoreduction was found to have a lower osmoticum optimum relative to aerobically maintained chloroplasts (50 millimolar versus 120 millimolar mannitol). 3-Phosphoglycerate (3-PGA) stimulated photoreduction up to a peak at 0.25 millimolar beyond which inhibition was observed. In the absence of 3-PGA, inorganic phosphate had no effect on photoreduction but in the presence of 3-PGA, inorganic phosphate also stimulated the reaction. Carbonyl cyanide-p-trifluoromethoxyphenylhydrazone and 2,5-dibromo-3-methyl-6-isopropyl-p-benzoquinone inhibited photoreduction but inhibition by the former could be partially overcome by exogenously added ATP. The intact plastid can also catalyze photoevolution of H(2) while lysed chloroplast extracts catalyzed the reduction of methyl viologen by H(2). Both reactions occurred at rates approximately one-third of those found in cells. The oxyhydrogen reaction in the presence or absence of CO(2) was not detected.

  12. Effect of light on fermentation and development of photosynthetic cells. Progress report, March 1, 1984-July 1, 1985

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, M.

    1985-07-01

    Intact Chlamydomonas cells ferment their starch in the dark to formate, acetate and ethanol in the ratios of 2:1:1 coupled to the evolution of H/sub 2/. Light causes an increase in H/sub 2/ but acetate and ethanol are minor products. On the addition of an uncoupler, acetate is produced while the presence of a plastoquinone antagonist restores ethanol formation. The latter is interpreted in terms of a chloroplastic respiratory pathway. Acetate is photoassimilated by Chlamydomonas cells under N/sub 2/ to CO/sub 2/ and H/sub 2/ with a stoichiometry indicating a light-dependent anaerobic glyoxylate cycle as the primary assimilatory route prior to conversion to lipid and carbohydrate. Isolated Chlamydomonas chloroplasts can fix CO/sub 2/ at rated between 25 to 50 micromole/mg chlorophyll per hour. The aerobically isolated chloroplasts can be adapted to a hydrogen metabolism. They can evolve H/sub 2/ (as compared to the whole cell), photoreduce CO/sub 2/ with H/sub 2/ and reduce methyl viologen at rates between 5 to 6 (15 to 20), 1.5 (4.5), 18 to 50 (35 to 100) micromole/mg chlorophyll per hour. The chloroplasts cannot perform the oxyhydrogen reaction. A Pasteur effect was detected in all algae tested. (DT)

  13. Thermodynamics and Kinetics of Guest-Induced Switching between “Basket Handle” Porphyrin Isomers

    Directory of Open Access Journals (Sweden)

    Alexander B. C. Deutman

    2014-04-01

    Full Text Available The synthesis and switching properties of two “basket handle” porphyrin isomers is described. The cis-oriented meso-phenyl groups of these porphyrins are linked at their ortho-positons via benzocrown-ether-based spacers, which as a result of slow atropisomerization are located either on the same side of the porphyrin plane (cis, or on opposite sides (trans. In solution, the cis-linked isomer slowly isomerizes in the direction of the thermodynamically more stable trans-isomer. In the presence of viologen (N,N'-dialkyl-4,4'-bipyridinium derivatives, which have different affinities for the two isomers, the isomerization equilibrium could be significantly influenced. In addition, the presence of these guests was found to enhance the rate of the switching process, which was suggested to be caused by favorable interactions between the positively charged guest and the crown ethers of the receptor, stabilizing the transition state energies of the isomerization reaction between the two isomers.

  14. Magnesium availability regulates the development of root hairs in Arabidopsis thaliana (L.) Heynh.

    Science.gov (United States)

    Niu, Yaofang; Chai, Rushan; Liu, Lijuan; Jin, Gulei; Liu, Miao; Tang, Caixian; Zhang, Yongsong

    2014-12-01

    Root hairs are reported to be plastic in response to nutrient supply, but relatively little is known about their development in response to magnesium (Mg) availability. Here, we showed that development of root hairs of Arabidopsis decreased progressively with increasing Mg supply, which was related to the initiation of new trichoblast files and likelihood of trichoblasts to form hairs. Tip-focused reactive oxygen species (ROS) and cytosolic Ca(2+) concentrations [(Ca(2+) )c] during elongation of root hairs were enhanced under low Mg but decreased under high Mg. Under low Mg, application of diphenylene iodonium (DPI) or BAPTA [1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid] blocked the enhanced development of root hairs and the opposite was true when the plants under high Mg were treated with phenazine methosulphate (PMS), methyl viologen (MV) or CaCl2 . Furthermore, Mg availability did not alter root hair growth in rhd2-1 mutant that contains lower levels of ROS and cytosolic [Ca(2+) ]c. Transcriptome data and qPCR results revealed a greater fraction of morphogenetic H-genes, and cell wall organization genes were up-regulated by low Mg but down-regulated by high Mg. Our data suggest a profound effect of Mg supply on the development of root hairs in Arabidopsis, through the characterized Ca(2+) and ROS signals that modulate the elongation of root hairs and the expression of root-hair morphogenetic genes. © 2014 John Wiley & Sons Ltd.

  15. Mechanistic understanding of monosaccharide-air flow battery electrochemistry

    Science.gov (United States)

    Scott, Daniel M.; Tsang, Tsz Ho; Chetty, Leticia; Aloi, Sekotilani; Liaw, Bor Yann

    Recently, an inexpensive monosaccharide-air flow battery configuration has been demonstrated to utilize a strong base and a mediator redox dye to harness electrical power from the partial oxidation of glucose. Here the mechanistic understanding of glucose oxidation in this unique glucose-air power source is further explored by acid-base titration experiments, 13C NMR, and comparison of results from chemically different redox mediators (indigo carmine vs. methyl viologen) and sugars (fructose vs. glucose) via studies using electrochemical techniques. Titration results indicate that gluconic acid is the main product of the cell reaction, as supported by evidence in the 13C NMR spectra. Using indigo carmine as the mediator dye and fructose as the energy source, an abiotic cell configuration generates a power density of 1.66 mW cm -2, which is greater than that produced from glucose under similar conditions (ca. 1.28 mW cm -2). A faster transition from fructose into the ene-diol intermediate than from glucose likely contributed to this difference in power density.

  16. Highly transparent electrochromic plastic device that changes to purple and to blue by increasing the potential

    Energy Technology Data Exchange (ETDEWEB)

    Pozo-Gonzalo, Cristina; Salsamendi, Maitane; Vinuales, Ana; Pomposo, Jose A.; Grande, Hans-Juergen [CIDETEC - Centre for Electrochemical Technologies, Paseo Miramon, 196, E-20009 Donostia, San Sebastian (Spain)

    2009-12-15

    We report the assembly and characterization of a highly transparent electrochromic device showing dual-coloration (purple and blue color change) using an innovative electrochromic formulation recently patented. This electrochromic formulation is composed of the three electroactive materials needed in a traditional electrochromic device (electrolyte, electrochromic and ion storage material) embedded in a polymeric matrix to reduce the chance of device malfunction by leaking and evaporation of the solvent. Two materials based on viologen, which show different electrochromic behaviors at 1.5 and 2.5 V, have been incorporated into the electrochromic formulation. Therefore, the electrochromic device was transparent in the bleach state but depending on the potential applied the final coloration was pink at 1.5 V and blue at 2.5 V. The maximum transparency of the device was 80% in the bleach state, 25.21% at 1.5 V when showing purple coloration and 3% at 2.5 V when showing blue coloration. The device presented a coloration efficiency (CE) of 136.6 cm{sup 2}/C and a coloring time of 6.5 s to achieve 90% of the maximum change in absorbance. The device exhibited a memory effect of 8 min estimated as the time needed to obtain the initial transparency. (author)

  17. Ultrafast response humidity sensor using supramolecular nanofibre and its application in monitoring breath humidity and flow

    Science.gov (United States)

    Mogera, Umesha; Sagade, Abhay A.; George, Subi J.; Kulkarni, Giridhar U.

    2014-01-01

    Measuring humidity in dynamic situations calls for highly sensitive fast response sensors. Here we report, a humidity sensor fabricated using solution processed supramolecular nanofibres as active resistive sensing material. The nanofibres are built via self- assembly of donor and acceptor molecules (coronene tetracarboxylate and dodecyl methyl viologen respectively) involved in charge transfer interactions. The conductivity of the nanofibre varied sensitively over a wide range of relative humidity (RH) with unprecedented fast response and recovery times. Based on UV-vis, XRD and AFM measurements, it is found that the stacking distance in the nanofibre decreases slightly while the charge transfer band intensity increases, all observations implying enhanced charge transfer interaction and hence the conductivity. It is demonstrated to be as a novel breath sensor which can monitor the respiration rate. Using two humidity sensors, a breath flow sensor was made which could simultaneously measure RH and flow rate of exhaled nasal breath. The integrated device was used for monitoring RH in the exhaled breath from volunteers undergoing exercise and alcohol induced dehydration. PMID:24531132

  18. Water radiolysis with heavy ions of energies up to 28 GeV-2: Extension of primary yield measurements to very high LET values

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, Shinichi [Department of Quantum Engineering and Systems Science, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Katsumura, Yosuke [Department of Nuclear Engineering and Management, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Naka, Ibaraki 319-1195 (Japan)], E-mail: katsu@n.t.u-tokyo.ac.jp; Lin Mingzhang [Advanced Science Research Center, Japan Atomic Energy Agency, 2-4 Shirakata-shirane, Tokai, Naka, Ibaraki 319-1195 (Japan); Muroya, Yusa [Nuclear Professional School, School of Engineering, University of Tokyo, 2-22 Shirakata-shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Maeyama, Takuya [Department of Nuclear Engineering and Management, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Murakami, Takeshi [Research Center of Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

    2008-10-15

    Measurements of primary g-values (at {approx}10{sup -7} s after the initial ionizing event) of e{sub aq}{sup -}, {sup {center_dot}}OH and H{sub 2}O{sub 2} were extended to the very high linear energy transfer (LET) region ({approx}700 eV/nm) near the Bragg peak. Heavy ions ({sup 4}He{sup 2+}, {sup 12}C{sup 6+}, {sup 20}Ne{sup 10+}, {sup 28}Si{sup 14+}, {sup 40}Ar{sup 18+} and {sup 56}Fe{sup 26+}) of energies up to 28 GeV were provided by the Heavy Ion Medical Accelerator in Chiba (HIMAC) of the National Institute of Radiological Sciences (NIRS) in Chiba, Japan. Energies of the ions were decreased down to about 10 MeV/u for {sup 4}He{sup 2+} using an energy absorber made of polymethylmethacrylate (PMMA) plates in order to vary the LET values. Beam was visualized after passing through the energy absorber using agarose gel of aqueous solution containing methyl viologen and sodium formate in order to determine how long ions can penetrate into water. Based on the information of the penetration depth of ions in samples, much attention was paid to dose correction and LET evaluation. The obtained data were plotted as a function of (Z{sub eff}/{beta}){sup 2} also instead of LET in order to discuss effects of physical track structures on product yields, resulted in better universality.

  19. Electronic transport mechanism and photocurrent generations of single-crystalline InN nanowires

    Science.gov (United States)

    Lee, Sunghun; Lee, Wonjoo; Seo, Kwanyong; Kim, Jinhee; Han, Sung-Hwan; Kim, Bongsoo

    2008-10-01

    Nanodevices using individual indium nitride nanowires are fabricated by e-beam lithography. The nanowires have diameters of 40-80 nm, lengths up to several tens of micrometres and single-crystalline nature. We observed ohmic I-V behaviour of InN nanowires above nearly 100 K, which is consistent with the pinning Fermi level of the metal electrode near the conduction band edge of InN nanowire. At low temperatures, the device shows typical semiconductor behaviour along with a quantum tunnelling effect through the Schottky barrier rather than thermally activated transport. The activation energy calculated above and below 80 K is 28.2 and 5.08 meV, respectively. We have also fabricated a photocurrent generation device using InN nanowires. The photocurrent of an acceptor-sensitizer dyad with di-(3-aminopropyl)-viologen (DAPV) and a Ru complex on an InN nanowires/ITO plate was 8.3 nA cm-2, which increased by 62.7% compared to that without InN nanowire layers.

  20. Gateway state-mediated, long-range tunnelling in molecular wires.

    Science.gov (United States)

    Sangtarash, Sara; Vezzoli, Andrea; Sadeghi, Hatef; Ferri, Nicolò; O'Brien, Harry M; Grace, Iain; Bouffier, Laurent; Higgins, Simon J; Nichols, Richard J; Lambert, Colin J

    2018-02-08

    If the factors controlling the decay in single-molecule electrical conductance G with molecular length L could be understood and controlled, then this would be a significant step forward in the design of high-conductance molecular wires. For a wide variety of molecules conducting by phase coherent tunnelling, conductance G decays with length following the relationship G = Ae -βL . It is widely accepted that the attenuation coefficient β is determined by the position of the Fermi energy of the electrodes relative to the energy of frontier orbitals of the molecular bridge, whereas the terminal anchor groups which bind to the molecule to the electrodes contribute to the pre-exponential factor A. We examine this premise for several series of molecules which contain a central conjugated moiety (phenyl, viologen or α-terthiophene) connected on either side to alkane chains of varying length, with each end terminated by thiol or thiomethyl anchor groups. In contrast with this expectation, we demonstrate both experimentally and theoretically that additional electronic states located on thiol anchor groups can significantly decrease the value of β, by giving rise to resonances close to E F through coupling to the bridge moiety. This interplay between the gateway states and their coupling to a central conjugated moiety in the molecular bridges creates a new design strategy for realising higher-transmission molecular wires by taking advantage of the electrode-molecule interface properties.