Sample records for carbamates

  1. Organophosphate and carbamate poisoning. (United States)

    King, Andrew M; Aaron, Cynthia K


    Organophosphates (OPs) and carbamates have a wide variety of applications, most commonly as pesticides used to eradicate agricultural pests or control populations of disease-carrying vectors. Some OP and carbamates have therapeutic indications such as physostigmine. Certain organophosphorus compounds, known as nerve agents, have been employed in chemical warfare and terrorism incidents. Both classes inhibit acetylcholinesterase (AChE) enzymes, leading to excess acetylcholine accumulation at nerve terminals. In the setting of toxicity from either agent class, clinical syndromes result from excessive nicotinic and muscarinic neurostimulation. The toxic effects from OPs and carbamates differ with respect to reversibility, subacute, and chronic effects. Decontamination, meticulous supportive care, aggressive antimuscarinic therapy, seizure control, and administration of oximes are cornerstones of management.

  2. Organic carbamates in drug design and medicinal chemistry. (United States)

    Ghosh, Arun K; Brindisi, Margherita


    The carbamate group is a key structural motif in many approved drugs and prodrugs. There is an increasing use of carbamates in medicinal chemistry and many derivatives are specifically designed to make drug-target interactions through their carbamate moiety. In this Perspective, we present properties and stabilities of carbamates, reagents and chemical methodologies for the synthesis of carbamates, and recent applications of carbamates in drug design and medicinal chemistry.

  3. Select small core structure carbamates exhibit high contact toxicity to "carbamate-resistant" strain malaria mosquitoes, Anopheles gambiae (Akron.

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    Dawn M Wong

    Full Text Available Acetylcholinesterase (AChE is a proven target for control of the malaria mosquito (Anopheles gambiae. Unfortunately, a single amino acid mutation (G119S in An. gambiae AChE-1 (AgAChE confers resistance to the AChE inhibitors currently approved by the World Health Organization for indoor residual spraying. In this report, we describe several carbamate inhibitors that potently inhibit G119S AgAChE and that are contact-toxic to carbamate-resistant An. gambiae. PCR-RFLP analysis was used to confirm that carbamate-susceptible G3 and carbamate-resistant Akron strains of An. gambiae carry wild-type (WT and G119S AChE, respectively. G119S AgAChE was expressed and purified for the first time, and was shown to have only 3% of the turnover number (k(cat of the WT enzyme. Twelve carbamates were then assayed for inhibition of these enzymes. High resistance ratios (>2,500-fold were observed for carbamates bearing a benzene ring core, consistent with the carbamate-resistant phenotype of the G119S enzyme. Interestingly, resistance ratios for two oxime methylcarbamates, and for five pyrazol-4-yl methylcarbamates were found to be much lower (4- to 65-fold. The toxicities of these carbamates to live G3 and Akron strain An. gambiae were determined. As expected from the enzyme resistance ratios, carbamates bearing a benzene ring core showed low toxicity to Akron strain An. gambiae (LC(50>5,000 μg/mL. However, one oxime methylcarbamate (aldicarb and five pyrazol-4-yl methylcarbamates (4a-e showed good to excellent toxicity to the Akron strain (LC(50 = 32-650 μg/mL. These results suggest that appropriately functionalized "small-core" carbamates could function as a resistance-breaking anticholinesterase insecticides against the malaria mosquito.

  4. Tolerance to the carbamate insecticide propoxur. (United States)

    Costa, L G; Hand, H; Schwab, B W; Murphy, S D


    Male mice were given the carbamate insecticide propoxur (2-isopropoxy phenyl methylcarbamate; Baygon) in the drinking water at weekly increasing concentrations (from 50 to 2000 ppm), for a period of 6 weeks. At the end of the treatment the LD50 for propoxur was significantly higher in the treated animals as compared with controls. Propoxur-treated animals were also resistant to the hypothermic effect of an acute administration of the same compound. Groups of mice were challenged with the cholinergic agonist carbachol at intervals during the drinking water dosing and at its end. No differences in sensitivity to carbachol acute toxicity were found between control and treated animals. Propoxur-tolerant animals were also not resistant to the hypothermic effect of oxotremorine, another cholinergic agonist. [3H]Quinuclidinyl benzilate ([3H]QNB) binding (a measure of muscarinic receptor density and affinity) in forebrain, hindbrain and ileum never differed in control and treated mice. The possibility that repeated administrations of propoxur induced increased metabolic inactivation was tested by measuring hexobarbital sleeping time and carboxylesterase activity in treated and control mice. No changes in tissue carboxylesterase activities occurred but hexobarbital sleeping time was significantly reduced in propoxur treated animals suggesting an induction of hepatic microsomal enzymes. These results suggest that tolerance to propoxur is not mediated by a decrease of cholinergic receptors, as reported for other acetylcholinesterase inhibitors, but possibly by an enhancement of its metabolism.

  5. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer. (United States)


    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Perfluoroalkyl aromatic carbamate... Significant New Uses for Specific Chemical Substances § 721.7200 Perfluoroalkyl aromatic carbamate modified...) The chemical substance identified generically as perfluoroalkyl aromatic carbamate modified...

  6. Synthesis and decreasing Aβ content evaluation of arctigenin-4-yl carbamate derivatives. (United States)

    Xu, Xingyu; Li, Cong; Lei, Min; Zhu, Zhiyuan; Yan, Jianming; Shen, Xu; Hu, Lihong


    A series of arctigenin-4-yl carbamate derivatives were synthesized and evaluated for potency in reducing β-amyloid (Aβ) content in HEK293-APPswe cells. Most of the arctigenin-4-yl aralkyl or aryl carbamate derivatives showed improved potency in reducing Aβ content. Among the synthesized compounds, arctigenin-4-yl (3-chlorophenyl)carbamate (20) exhibited the strongest potency with 78.7% Aβ content reduction at 20μM. Furthermore, the effect of arctigenin-4-yl (4-chlorophenyl)carbamate (19) and arctigenin-4-yl (3-chlorophenyl)carbamate (20) on lowing Aβ content was better than arctigenin under the concentrations of 1, 10 and 20μM.

  7. A computational quantitative structure-activity relationship study of carbamate anticonvulsants using quantum pharmacological methods. (United States)

    Knight, J L; Weaver, D F


    A pattern recognition quantitative structure-activity relationship (QSAR) study has been performed to determine the molecular features of carbamate anticonvulsants which influence biological activity. Although carbamates, such as felbamate, have been used to treat epilepsy, their mechanisms of efficacy and toxicity are not completely understood. Quantum and classical mechanics calculations have been exploited to describe 46 carbamate drugs. Employing a principal component analysis and multiple linear regression calculations, five crucial structural descriptors were identified which directly relate to the bioactivity of the carbamate family. With the resulting mathematical model, the biological activity of carbamate analogues can be predicted with 85-90% accuracy.

  8. The Target of Benzimidazole Carbamate Against Cysticerci cellulosae

    Institute of Scientific and Technical Information of China (English)

    LI Qing-zhang; HAO Yan-hong; GAO Xue-jun; GAO Wen-xue; ZHAO Bing


    To study the target of benzimidazole carbamate drugs against Cysticerci cellulosae and give a theoretical basis for type evolution and new drug design, the changes of key enzyme activities and metabolite contents in the pathway of energy metabolism in C. cellulosae in vitro and in vivo were tested with albendazole and oxfendazole, respectively. Both albendazole and oxfendazole inhibited the pathways of anaerobic glycolysis, partial inversed tricarboxylic acid cycle of Taenia Solium oncosphere, immature and mature Cysticerci in vitro, and immature and mature Cysticerci in vivo to a certain degree, and enhanced fat decomposing, amino acid decomposing, xanthine decomposing metabolism, and on the other hand, the absorption of glucose was hindered; furthermore, both albendazole and oxfendazole inhibited the activities of the fumaric reductase (FR) complex noncompetently in vitro. Benzimidazole carbamate drugs could inhibit the activities of FR complex noncompetently and hinder the absorption of glucose.

  9. Carbamate and Organophosphorus Nematicides: Acetylcholinesterase inhibition and Effects on Dispersal. (United States)

    Pree, D J; Townshend, J L; Archibald, D E


    The sensitivities of acetylcholinesterases (ACHE) from the fungus-feeder Aphelenchus avenae and the plant-parasitic species Helicotylenchus dihystera and Pratylenchus penetrans and the housefly, Musca domestica, were compared using a radiometric assay which utilized H(3) acetylcholine as a substrate. Nematode ACHE were generally less sensitive to inhibition by organophosphorns and carbamate pesticides than were ACHE from the housefly. ACHE from the plant-parasitic species and A. avenae were generally similar in sensitivity. In soil, carbamates were more toxic than the organophosphorus pesticides to A. avenae. All pesticides tested affected nematode movement, but fenamiphos was more inhibitory than others. The effects on dispersal of nematodes may be an important mechanism in control by some nematicides.

  10. Occupational allergic contact dermatitis from xanthates and carbamates in mining processes. (United States)

    Sasseville, Denis; Muhn, Channy Y; Al-Sowaidi, Mowza


    The objective of this article is to describe allergic contact dermatitis from sodium isopropyl xanthate, potassium amyl xanthate, and carbamates in a geotechnician, to discuss possible cross-reactions, and to report the widespread use of carbamates and mercaptobenzothiazole in mining processes.

  11. 40 CFR 268.39 - Waste specific prohibitions-spent aluminum potliners; reactive; and carbamate wastes. (United States)


    ... aluminum potliners; reactive; and carbamate wastes. 268.39 Section 268.39 Protection of Environment... Land Disposal § 268.39 Waste specific prohibitions—spent aluminum potliners; reactive; and carbamate...-U411 are prohibited from land disposal. In addition, soil and debris contaminated with these wastes...

  12. Subchronic Toxicity Study in Rats of Two New Ethyl-Carbamates with Ixodicidal Activity

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    María Guadalupe Prado-Ochoa


    Full Text Available Female and male Wistar rats were used to determine the subchronic oral toxicities of two new ethyl-carbamates with ixodicidal activities (ethyl-4-bromphenyl-carbamate and ethyl-4-chlorphenyl-carbamate. The evaluated carbamates were administered in the drinking water (12.5, 25 and 50 mg/kg/day for 90 days. Exposure to the evaluated carbamates did not cause mortality or clinical signs and did not affect food consumption or weight gain. However, exposure to these carbamates produced alterations in water consumption, hematocrit, percentages of reticulocytes, plasma proteins, some biochemical parameters (aspartate aminotransferase, gamma-glutamyl transpeptidase, cholinesterase, and creatinine activities, thiobarbituric acid reactive substances, and the relative weight of the spleen. Histologically, slight pathological alterations were found in the liver that were consistent with the observed biochemical alterations. The nonobserved adverse effect levels (NOAELs of the evaluated carbamates were 12.5 mg/kg/day for both the female and male rats. The low severity and reversibility of the majority of the observed alterations suggest that the evaluated carbamates have low subchronic toxicity.

  13. Evaluation of carbamate insecticides as chemotherapeutic agents for cancer

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    Mohd. Amanullah


    Full Text Available Background: Cancer chemotherapy has already been in practice by the use of toxins and some of the specific poisonous compounds of cyanide derivatives. Carbamate insecticides inhibit cellular metabolism including energy, protein, and nucleic acid metabolism, thereby, causing cell regression and death. Aim: Preliminary evaluation of three carbamate insecticides, namely, baygon, carbaryl, and carbofuran as chemotherapeutic agents for cancer is undertaken in the present study. Materials and Methods: The toxicity of carbamates on squamous cell carcinoma was assessed in-vitro using dye binding tests. Cells were grown in microtitration ELISA plates, as adherent cultures, for six hours, and then exposed to the drugs for 2, 4, 8, and 12 hours, and finally stained with neutral red, to assess the viable cell number, and with methylene blue for the determination of protein in the monolayer. Optical density was read in an ELISA reader. Statistical Analysis: The data obtained during the experiment was subjected to statistical analysis by using the student ′t′ test. Results: The results indicated that the percentage of the viable cell number reduced with an increase in the time of exposure of the drugs. Exposure of the tumor cells to the drugs for 12 hours detached them completely from the wells, and hence, all the cells were washed out. Exposure of the drugs prior to the establishment of the culture in-vitro resulted in the non-formation of the monolayer in the wells. Conclusions: Among the three drugs studied, the survival percent was least with carbaryl treatment followed by baygon, and with carbofuran treatment it was almost near to control group.

  14. Brazilian vodkas have undetectable levels of ethyl carbamate

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    Elainy V. S. Pereira


    Full Text Available While in Europe vodka is mainly derived from potatoes or cereals, a large proportion of Brazilian vodka is likely obtained from sugarcane, which contains ethyl carbamate (EC precursors. EC, in addition to several other contaminants and congeners, were investigated in 32 samples of Brazilian vodka. All samples complied with the Brazilian regulations for congeners and contaminants, having EC content below 0.01 mg/L (detection limit. These results are probably related to the processing of vodka, in particular the use of extractive and rectifying stainless steel distillation columns, which allow the production of high strength spirits with low levels of congeners and contaminants.

  15. Piezoelectric Biosensors for Organophosphate and Carbamate Pesticides: A Review

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    Giovanna Marrazza


    Full Text Available Due to the great amount of pesticides currently being used, there is an increased interest for developing biosensors for their detection. Among all the physical transducers, piezoelectric systems have emerged as the most attractive due to their simplicity, low instrumentation costs, possibility for real-time and label-free detection and generally high sensitivity. This paper presents an overview of biosensors based on the quartz crystal microbalance, which have been reported in the literature for organophosphate and carbamate pesticide analysis.

  16. Ultra-Trace Determination of Methyl Carbamate and Ethyl Carbamate in Local Wines by GC-FID Following Pre concentration with C18-SPE

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    Supawadee Sarawan


    Full Text Available An analytical method is described for ultra-trace determination of methyl carbamate and ethyl carbamate in locally produced fruit wines. The quantitative analysis involves with dichloromethane extraction followed by 30-fold preconcentration using C18 SPE prior to measurement by capillary GC-FID. Under the optimized conditions, a good linearity of their calibration curves was obtained in the range of 0.1-50.0 mg/L with r2 > 0.994. LOD and LOQ were 3.3-16.7 µg/L and 11.1-55.6 µg/L, respectively. The averaged recovery of these carbamates was ranged of 82.2-95.2% with RSD < 8.76%. The procedure was applied to determine both carbamate residues in various local wine samples. It was found that the concentration range of methyl carbamate (6.9-24.1 µg/L was rather fluctuated and higher than that of ethyl carbamate (2.6-4.3 µg/L, suggesting that is a certain residual background contamination naturally occurring in the wine fermentation.

  17. Simultaneous determination of airborne carbamates in workplace by high performance liquid chromatography with fluorescence detection. (United States)

    Li, Hong-Ping; Li, Jen-Hou; Li, Gwo-Chen; Jen, Jen-Fon


    A high performance liquid chromatography with fluorescence (HPLC-F) detector was examined to simultaneous determination of airborne carbamates in the workplace of manufactory. The OVS-2 air sampling tube filled with glass fiber filter or quartz fiber and combined filter/XAD-2 were evaluated to collect nine commonly used carbamates (Carbofuran, Isoprocarb, Methomyl, Metolcarb, Thiodicarb, Carbaryl, Oxamyl, Methiocarb, and Prpoxur) from the air of manufactory in high humidity country. After being extracted with acetonitrile from sampling tubes, the carbamates were determined by high performance liquid chromatography with fluorescence detection posterior to on-line derivatization. The collection of carbamates and the recovery of extraction from glass wool fiber in several concentration levels, and from quartz filter were evaluated. The storage stability of carbamates was also tested. Results indicated that the HPLC-fluorescence method offers satisfactory resolution and sensitivity in carbamate analysis. With the glass fiber filter and combined filter/XAD-2, the Carbofuran, Isoprocarb, Methomyl, Metolcarb, and Thiodicarb were stable for a 28-day storage test, Carbaryl and Oxamyl for 14 days, and Methiocarb and Prpoxur for 7 days. All of these pesticides were with detection limit of 3mugm(-3). It is suited for environmental monitoring. The airborne carbamates in different areas of the manufactory were measured.

  18. Biodegradation of a carbamate pesticide, Propoxur, in rat tissues. (United States)

    Kumar, R; Madhavi, N B; Sharma, C B


    Propoxur (Baygon, 2-isopropoxyphenyl N-methylcarbamate) is a carbamate pesticide commonly used against house insects. When the insecticide was administered intramuscularly in rats it was converted to a new metabolite which was found to be present in the serum, liver, kidney and brain 6 h after the administration of the pesticide. The metabolite was purified by high performance liquid to chromatography and comparison of the infrared spectra of Propoxur and the metabolite showed that a deamination reaction was responsible for the formation of the metabolite from the parent pesticide. The pesticide also induced haematological changes such as an increased level of total bilubrin, amylase and glutamic-oxalacetic transaminase and decrease of cholinesterase activity, indicating damage of the liver and nervous system in rats.

  19. Hydrogels for osteochondral repair based on photocrosslinkable carbamate dendrimers. (United States)

    Degoricija, Lovorka; Bansal, Prashant N; Söntjens, Serge H M; Joshi, Neel S; Takahashi, Masaya; Snyder, Brian; Grinstaff, Mark W


    First generation, photocrosslinkable dendrimers consisting of natural metabolites (i.e., succinic acid, glycerol, and beta-alanine) and nonimmunogenic poly(ethylene glycol) (PEG) were synthesized divergently in high yields using ester and carbamate forming reactions. Aqueous solutions of these dendrimers were photocrosslinked with an eosin-based photoinitiator to afford hydrogels. The hydrogels displayed a range of mechanical properties based on their structure, generation size, and concentration in solution. All of the hydrogels showed minimal swelling characteristics. The dendrimer solutions were then photocrosslinked in situ in an ex vivo rabbit osteochondral defect (3 mm diameter and 10 mm depth), and the resulting hydrogels were subjected to physiologically relevant dynamic loads. Magnetic resonance imaging (MRI) showed the hydrogels to be fixated in the defect site after the repetitive loading regimen. The ([G1]-PGLBA-MA) 2-PEG hydrogel was chosen for the 6 month pilot in vivo rabbit study because this hydrogel scaffold could be prepared at low polymer weight (10 wt %) and possessed the largest compressive modulus of the 10% formulations, a low swelling ratio, and contained carbamate linkages, which are more hydrolytically stable than the ester linkages. The hydrogel-treated osteochondral defects showed good attachment in the defect site and histological analysis showed the presence of collagen II and glycosaminoglycans (GAGs) in the treated defects. By contrast, the contralateral unfilled defects showed poor healing and negligible GAG or collagen II production. Good mechanical properties, low swelling, good attachment to the defect site, and positive in vivo results illustrate the potential of these dendrimer-based hydrogels as scaffolds for osteochondral defect repair.

  20. Cumulative risk assessment of the intake of organophosphorus and carbamate pesticides in the Danish diet

    DEFF Research Database (Denmark)

    Jensen, A. F.; Petersen, Annette; Granby, Kit


    The aim of the study is to evaluate the potential cumulative effects of organophosphorus and carbamate pesticides that act through a common mechanism of toxicity, and to assess the long- and short-term risks for the Danish population. The intake estimates are based on dietary intake data collected...... in the Danish nation-wide food consumption survey in 1995. The pesticide data are based on the Danish pesticide residue-monitoring programme from 1996-2001. The amount of 35 organophosphorus pesticides and carbamates were included in the cumulative risk assessment. Processing factors, such as reduction...... of pesticide levels by rinsing and peeling, were applied in the exposure assessment. The "Toxicity Equivalence Factor" (TEF) approach was used to normalise the toxicity of the different organophosphorus and carbamate pesticides. Cumulative chronic exposure of organophosphorus and carbamates pesticides via...

  1. Comparative Evaluation of Carbamates as Prophylactic Agents against Organophosphate Intoxication Rats

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    A. K. Chatterjee


    Full Text Available Investigates the effects of two well-known carbamates, physostigmine and pyridostigmine against organophosphorous compound and nerve gas toxicity. Physostigmine pretreatment for 30 min enhanced the survival time of rats against DFP intoxication whereas it did not have any effect with sarin poisoning. However, pyridostigmine pretreatment did not produce any significant effect on survival time either against DFP or sarin intoxication. Treatment with atropine along with carbamates further enhanced significantly the survival time against DFP poisoning.

  2. Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea under mild conditions

    Institute of Scientific and Technical Information of China (English)

    Jun Jie Gao; Hui Quan Li; Yi Zhang


    Synthesis of methyl N-phenyl carbamate from dimethyl carbonate and 1,3-diphenyl urea was investigated under atmospheric pressure. The results showed that homogenous catalyst sodium methoxide had the excellent activity to efficiently catalyze the synthesis of methyl N-phenyl carbamate under atmospheric pressure.

  3. Benzimidazole Carbamate Residues in Milk: Detection by SPR Biosensor; using a Modified QuEChERS Method for Extraction (United States)

    A surface plasmon resonance (SPR) biosensor screening assay was developed and validated to detect 11 benzimidazole carbamate (BZT) veterinary drug residues in milk. The polyclonal antibody used was raised in sheep against a methyl 5 (6)-[(carboxypentyl)-thio]-2-benzimidazole carbamate protein conjug...

  4. Assessment of Acute Oral and Dermal Toxicity of 2 Ethyl-Carbamates with Activity against Rhipicephalus microplus in Rats

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    María Guadalupe Prado-Ochoa


    Full Text Available The acute oral and dermal toxicity of two new ethyl-carbamates (ethyl-4-bromophenyl-carbamate and ethyl-4-chlorophenyl-carbamate with ixodicide activity was determined in rats. The oral LD50 of each carbamate was 300 to 2000 mg/kg, and the dermal LD50 of each carbamate was >5000 mg/kg. Clinically, the surviving rats that had received oral doses of each carbamate showed decreased weight gain (P<0.05 and had slight nervous system manifestations. These clinical signs were evident from the 300 mg/kg dose and were reversible, whereas the 2000 mg/kg dose caused severe damage and either caused their death or was motive for euthanasia. At necropsy, these rats had dilated stomachs and cecums with diffuse congestion, as well as moderate congestion of the liver. Histologically, the liver showed slight degenerative lesions, binucleated hepatocytes, focal coagulative necrosis, and congestion areas; the severity of the lesions increased with dosage. Furthermore, an slight increase in gamma-glutamyltransferase, lactate dehydrogenase, and creatinine was observed in the plasma. The dermal application of the maximum dose (5000 mg/kg of each carbamate did not cause clinical manifestations or liver and skin alterations. This finding demonstrates that the carbamates under study have a low oral hazard and low acute dermal toxicity.

  5. Influence of pretreatment of carbamates on dynamic pulmonary mechanics in rats exposed to sarin aerosols. (United States)

    Husain, K; Kumar, P; Vijayaraghavan, R; Singh, R; Das Gupta, S


    The effect of pretreatment of two carbamates, pyridostigmine and physostigmine on dynamic pulmonary mechanics has been studied in rats exposed to sarin aerosols. Sign-free dose of pyridostigmine (0.075 mg/kg, i.m.) or physostigmine (0.1 mg/kg, i.m.) did not significantly alter the parameters of the dynamic pulmonary mechanics 20 min after treatment. However, sarin (51.2 mg/m3, for 15 min) depressed the respiratory rate, air flow and minute volume and enhanced the transthoracic pressure and tidal volume. Pretreatment with carbamates 20 min prior to sarin exposure significantly modified or counteracted the above induced changes. It is concluded that the protective effect of carbamates is mainly due to the correction of respiratory changes caused by sarin aerosols in rats.

  6. Carbamate stabilities of sterically hindered amines from quantum chemical methods: relevance for CO2 capture. (United States)

    Gangarapu, Satesh; Marcelis, Antonius T M; Zuilhof, Han


    The influence of electronic and steric effects on the stabilities of carbamates formed from the reaction of CO2 with a wide range of alkanolamines was investigated by quantum chemical methods. For the calculations, B3LYP, M11-L, MP2, and spin-component-scaled MP2 (SCS-MP2) methods were used, coupled with SMD and SM8 solvation models. A reduction in carbamate stability leads to an increased CO2 absorption capacity of the amine and a reduction of the energy required for solvent regeneration. Important factors for the reduction of the carbamate stability were an increase in steric hindrance around the nitrogen atom, charge on the N atom and intramolecular hydrogen bond strength. The present study indicates that secondary ethanolamines with sterically hindering groups near the N atom show significant potential as candidates for industrial CO2-capture solvents.

  7. Plant-parasitic Nematode Acetylcholinesterase Inhibition by Carbamate and Organophosphate Nematicides. (United States)

    Opperman, C H; Chang, S


    The sensitivity of acetylcholinesterases (ACHE) isolated from the plant-parasitic nematodes Meloidogyne arenaria, M. incognita, and Heterodera glycines and the free-living nematode Caenorhabditis elegans to carbamate and organophosphate nematicides was examined. The AChE from plant-parasitic nematode species were more sensitive to carbamate inhibitors than was AChE from C. elegans, but response to the organophosphates was approximately equivalent. The sulfur-containing phosphate nematicides were poor inhibitors of nematode acetylcholinesterase, but treatment with an oxidizing agent greatly improved inhibition. Behavioral bioassays with living nematodes revealed a poor relationship between enzyme inhibition and expression of symptoms in live nematodes.

  8. Efficient preparation of carbamates by Rh-catalysed oxidative carbonylation: unveiling the role of the oxidant. (United States)

    Iturmendi, Amaia; Iglesias, Manuel; Munárriz, Julen; Polo, Victor; Pérez-Torrente, Jesús J; Oro, Luis A


    The synthesis of a wide variety of carbamates from amines, alcohols and carbon monoxide has been achieved by means of a Rh-catalysed oxidative carbonylation reaction that uses Oxone as a stoichiometric oxidant. In-depth studies on the reaction mechanism shed light on the intimate role of Oxone in the catalytic cycle.

  9. The Use and Effect of Carbamate Insecticide on Animal Health and Products

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    Full Text Available The use of carbamate in Indonesia is relatively new, in particular after prohibition on the use of most organochlorines (OC. Carbamates that commonly used for agricultural activities are carbofuran (Furadan, aldicarb (Temik and carbaryl (Sevin. When properly used, they will provide benefit, but misuse of insecticides would affect productivity, poisoning, public health problems, environmental contamination and residues in foods. A monitoring result of carbamate used in Java indicates that carbofurans were detected in soils (0,8 – 56,3 ppb; water (0,1 – 5,0 ppb; rice (nd – 5,0 ppb; soybeans (1,2 – 610 ppb; animal feed (12 – 102 ppb; beef (110 – 269 ppb; and sera of beef cattle (167 – 721 ppb. The residue level was above the maximum residue limits (MRL released by Indonesian Standardization Agency (Badan Standardisasi Nasional in some samples. The presence of carbofuran in foods should be taken into account since the carbofuran is regarded highly toxic for public and animal health. This paper describes the toxicity of carbamate, clinical signs of poisoning, residue in foods and environment, handling of poisoning and residue control.

  10. Design, synthesis, and evaluation of carbamate-substituted analogues of (+)-discodermolide. (United States)

    Smith, Amos B; Freeze, B Scott; Lamarche, Matthew J; Hirose, Tomoyasu; Brouard, Ignacio; Rucker, Paul V; Xian, Ming; Sundermann, Kurt F; Shaw, Simon J; Burlingame, Mark A; Horwitz, Susan Band; Myles, David C


    [Structure: see text] The design, syntheses, and biological evaluation of 22 totally synthetic analogues of the potent microtubule-stabilizing agent (+)-discodermolide (1) have been achieved. Structure-activity relationships of the C(19) carbamate were defined, exploiting two synthetically simplified scaffolds, as well as the parent (+)-discodermolide framework.


    Microbe liquid chromatography and positive ion electrospray mass spectrometry are applied to the determination of 16 carbamate, urea, and thiourea pesticides and herbicides in water. The electrospray mass spectra of the analytes were measured and are discussed and mobile phase m...

  12. Baygon-A New Carbamate Insecticide and its Evaluation Against Cockroaches by a Simple New Technique

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    R. N. Varma


    Full Text Available Baygon a new carbamate insecticide has been tested for its efficacy against cockroaches, Periplanta americana Linn. in relation to Sumithion and Malathion by a simple technique developed by the authors. It has been found to be much superior in producing Knock-down and kill of the insects as compared to Sumithion and Malathion.

  13. Carbamate Stabilities of Sterically Hindered Amines from Quantum Chemical Methods: Relevance ofr CO2 Capture

    NARCIS (Netherlands)

    Gangarapu, S.; Marcelis, A.T.M.; Zuilhof, H.


    The influence of electronic and steric effects on the stabilities of carbamates formed from the reaction of CO2 with a wide range of alkanolamines was investigated by quantum chemical methods. For the calculations, B3LYP, M11-L, MP2, and spin-component-scaled MP2 (SCS-MP2) methods were used, coupled

  14. Detection of benzimidazole carbamates and amino metabolites in liver by surface plasmon resonance-biosensor (United States)

    Two surface plasmon resonance (SPR) biosensor screening assays were developed and validated to detect 11 benzimidazole carbamate (BZT) and four amino-benzimidazole veterinary drug residues in liver tissue. The assays used polyclonal antibodies, raised in sheep, to detect BZTs and amino-benzimidazole...

  15. Acetylcholinesterase inhibition as an indicator of organophosphate and carbamate poisoning in Kenyan agricultural workers.

    NARCIS (Netherlands)

    Ohayo-Mitoko, G.J.A.; Heederik, D.; Kromhout, H.; Omondi, B.E.O.; Boleij, J.S.M.


    Acetylcholinesterase inhibition was determined for 666 Kenyan agricultural workers; 390 (58.6%) mainly pesticide applicators exposed to organophosphate and carbamate pesticides and 276 (41.4%) unexposed controls from four rural agricultural areas during 1993 and 1994. Baseline levels were depressed

  16. Fenugreek hydrogel–agarose composite entrapped gold nanoparticles for acetylcholinesterase based biosensor for carbamates detection

    Energy Technology Data Exchange (ETDEWEB)

    Kestwal, Rakesh Mohan; Bagal-Kestwal, Dipali; Chiang, Been-Huang, E-mail:


    A biosensor was fabricated to detect pesticides in food samples. Acetylcholinesterase was immobilized in a novel fenugreek hydrogel–agarose matrix with gold nanoparticles. Transparent thin films with superior mechanical strength and stability were obtained with 2% fenugreek hydrogel and 2% agarose. Immobilization of acetylcholinesterase on the membrane resulted in high enzyme retention efficiency (92%) and a significantly prolonged shelf life of the enzyme (half-life, 55 days). Transmission electron microscopy revealed that, gold nanoparticles (10–20 nm in diameter) were uniformly dispersed in the fenugreek hydrogel–agarose–acetylcholinesterase membrane. This immobilized enzyme-gold nanoparticle dip-strip system detected various carbamates, including carbofuran, oxamyl, methomyl, and carbaryl, with limits of detection of 2, 21, 113, and 236 nM (S/N = 3), respectively. Furthermore, the fabricated biosensor exhibited good testing capabilities when used to detect carbamates added to various fruit and vegetable samples. - Highlights: • Acetylcholinesterase (AChE) dip-strip biosensor fabricated to detect carbamates. • AChE entrapped in fenugreek hydrogel–agarose matrix with gold nanoparticles (GNPs). • High enzyme retention efficiency (92%) and shelf life (half-life, 55 days). • Detection limits of carbofuran, oxamyl and methomyl: 2, 21 and 113 nM. • The biosensor had good testing capabilities to detect carbamates in food samples.

  17. Investigation of kinetic interactions between approved oximes and human acetylcholinesterase inhibited by pesticide carbamates. (United States)

    Wille, Timo; Kaltenbach, Lisa; Thiermann, Horst; Worek, Franz


    Carbamates are widely used for pest control and act primarily by inhibition of insect and mammalian acetylcholinesterase (AChE). Accidental or intentional uptake of carbamates may result in typical signs and symptoms of cholinergic overstimulation which cannot be discriminated from those of organophosphorus pesticide poisoning. There is an ongoing debate whether standard treatment with atropine and oximes should be recommended for human carbamate poisoning as well, since in vitro and in vivo animal data indicate a deleterious effect of oximes when used in combination with the N-methyl carbamate carbaryl. Therefore, we performed an in vitro kinetic study to investigate the effect of clinically used oximes on carbamoylation and decarbamoylation of human AChE. It became evident that pralidoxime and obidoxime in therapeutic concentrations aggravate the inhibition of AChE by carbaryl and propoxur, with obidoxime being substantially more potent compared to 2-PAM. However, obidoxime had no impact on the decarbamoylation kinetics. Hence, the administration of 2-PAM and especially of obidoxime to severely propoxur and carbaryl poisoned humans cannot be recommended.

  18. Discovery and optimization of adamantyl carbamate inhibitors of 11β-HSD1. (United States)

    Tice, Colin M; Zhao, Wei; Krosky, Paula M; Kruk, Barbara A; Berbaum, Jennifer; Johnson, Judith A; Bukhtiyarov, Yuri; Panemangalore, Reshma; Scott, Boyd B; Zhao, Yi; Bruno, Joseph G; Howard, Lamont; Togias, Jennifer; Ye, Yuan-Jie; Singh, Suresh B; McKeever, Brian M; Lindblom, Peter R; Guo, Joan; Guo, Rong; Nar, Herbert; Schuler-Metz, Annette; Gregg, Richard E; Leftheris, Katerina; Harrison, Richard K; McGeehan, Gerard M; Zhuang, Linghang; Claremon, David A


    Synthesis of 2-adamantyl carbamate derivatives of piperidines and pyrrolidines led to the discovery of 9a with an IC(50) of 15.2 nM against human 11β-HSD1 in adipocytes. Optimization for increased adipocyte potency, metabolic stability and selectivity afforded 11k and 11l, both of which were >25% orally bioavailable in rat.

  19. Probabilistic assessment of the cumulative dietary acute exposure of the population of Denmark to organophosphorus and carbamate pesticides

    DEFF Research Database (Denmark)

    Jensen, Bodil Hamborg; Petersen, Annette; Christensen, Tue


    Organophosphorus and carbamate pesticides are acetylcholinesterase-inhibiting pesticides and as such have a common mode of action. We assessed the cumulative acute exposure of the population of Denmark to 25 organophosphorus and carbamate pesticide residues from the consumption of fruit, vegetables...... the nationwide dietary survey conducted in 2000-2002. Contributions from 43 commodities were included in the calculations. We used the relative potency factor (RPF) approach to normalize the toxicity of the various organophosphorus and carbamate pesticides to the two index compounds chlorpyriphos...

  20. The effects of some carbamate local anaesthetics on the guinea-pig ileum. (United States)

    Bezeková, M; Bauer, V


    The action of some carbamate local anaesthetics, pentacaine, BK-52 and heptacaine, was compared in the guinea-pig ileum with that of classic local anaesthetics, procaine and trimecaine. Contractions of the ileum were evoked by transmural stimulation, nicotine, acetylcholine, noradrenaline, histamine, K+ and Ba++. Although the evoked contractions were inhibited by all the local anaesthetics, there was a marked difference in their ability to influence the smooth muscle activation induced by different stimuli. The differences among the IC50 values were slight in the case of pentacaine, moderate in the case of trimecaine and BK-52 and large in the case of procaine and heptacaine. It is suggested that besides their effects on the unmyelinated autonomic nerves, the carbamate local anaesthetics studied can also affect the smooth muscle membrane, similarly to the classic agents. The mechanism of their direct effect is discussed.

  1. Sulfonamide and carbamate derivatives of 6-chloropurine: synthesis, characterization and antimicrobial activity evaluation

    Directory of Open Access Journals (Sweden)

    K. Venkata Narayana


    Full Text Available A series of new sulfonamide derivatives, 9-(substitutedbenzenesulfonyl-6-chloro-9H-purines 7(a-e and carbamate derivatives, 6-chloro-purine-9-carboxylic acid substituted alkyl/arylester 9(a-d, have been synthesized through an intermediate, sodium salt of 6-chloro-9(H-purine (6 which was prepared by the treatment of 6-chloro-9(H-purine (4 with sodium hydride. Structures of the newly synthesized compounds were elucidated by IR, NMR ( 1H and 13C, mass spectra and elemental analysis. Antimicrobial activity against three bacterial strains and three fungal strains at two different concentrations, 100 and 200 µg/mL including MIC values was investigated. Bio-screening data disclosed that most of the sulfonamide derivatives, 7a, 7c and 7d, and one carbamate derivative 9a showed promising antimicrobial activity having MIC values in the range of 18.0-25.0 µg/mL.

  2. Quantitative analysis of ethyl carbamate in Korean alcoholic beverages by chromatography with mass selective detection

    Energy Technology Data Exchange (ETDEWEB)

    Park, G.B.; Lee, S.G. [Korea Research Institute of Chemical Technology, Taejon (Korea)


    In order to determine the contents of ethyl carbamate in Korean traditional alcoholic beverages and general beverages, GC/MS-SIM method was used after extraction of beverages with dichloromethane. The contents of ethyl carbamate in Korean traditional alcoholic beverages, non-distilled alcohol, and whisky were detected in the rage of 4.6-50.2 {mu}g/L, 27.8-45.4 {mu}g/L, and 24.8-55.1 {mu}g/L, respectively. The recoveries were ranged from 83.3 to 104.8 %. The values of relative standard deviation were ranged from 1.8 to 14.8% and the detection limit was 0.3 {mu}g/L. (author). 13 refs., 2 tabs., 4 figs.

  3. Organophosphorus and carbamates residues in milk and feedstuff supplied to dairy cattle


    Rafael Fagnani; Vanerli Beloti; Ana Paula P. Battaglini; Dunga,Karen da S.; Ronaldo Tamanini


    Considering acute and chronic toxicity effects on human and animal health caused by pesticide residues in food, this study aimed to analyze organophosphorate (OP) and carbamate (CB) in feedstuff and water destined for dairy cattle, as well as in the milk produced by these animals, through gas chromatography (GC). In the Agreste region of Pernambuco, Brazil, 30 raw milk samples and all components of the animals' diet were collected from several farms. Out of the 30 milk of milk analyzed, six (...

  4. Efficient Lewis Acids Catalyzed Aza-Michael Reactions of Enones with Carbamates

    Institute of Scientific and Technical Information of China (English)

    XIA Chun-Gu; XU Li-Wen


    The a-amino carbonyl functionality is not only a segment of biologically important natural products but also a versatile intermediate for the synthesis of nitrogen-containing compounds.1 The development of novel synthetic methods leading to a-amino ketone, a-amino acids or their derivatives has attracted much attention in organic synthesis.2 Among the traditional methods for generating a-amino carbonyl compounds, Mannich-type reaction is one of the classical and powerful methods.3 However, the classic Mannich reaction presents serious disadvantages, for example, there is still a drawback in that the silyl enolates have to be prepared from the corresponding carbonyl compounds. Alternatively, aza-Michael additions can be used to create carbon-heteroatom bonds by reaction of a,a-unsaturated carbonyl compounds with amines. Although recent advances have made this route more attractive, development of cheaper, simpler, and more efficient metal catalyst, especially which can be applied to chalcone, is highly desirable.In this paper, we demonstrated that the first aza-Michael reaction of chalcone with a less nucleophilic carbamates can be accomplished on Me3SiCFFeCl3 catalyst system under very mild conditions. Apart from experimental simplicity, the advantages of this methodology are the use of a very cheap Lewis acid catalyst and the insensitivity of the reaction mixture towards air and moisture.catalyst for aza-Michael reaction of chalcone and cyclic enones with carbamates. And with the cyclic enones with carbamates in dichloromethane at room temperature were also investigated. In this conjugate addition reaction, good to excellent yields of a-amino ketones were obtained with system could also mediates aza-Michael addition of carbamates to chalcone and derivatives.These new strategies opened efficient procedures for the synthesis of a-amino ketones under mild conditions.

  5. Management of exogenous intoxication by carbamates and organophosphates at an emergency unit

    Directory of Open Access Journals (Sweden)

    Sydney Correia Leão


    Full Text Available Summary Objectives: to evaluate and indicate the procedure to be followed in the health unit, both for diagnosis and the treatment of acute exogenous intoxications by carbamates or organophosphates. Methods: a descriptive study based on retrospective analysis of the clinical history of patients diagnosed with intoxication by carbamates or organophosphates admitted at the emergency unit of the Hospital de Urgências de Sergipe Governador João Alves (HUSE between January and December of 2012. Some criteria were evaluated, such as: intoxicating agent; patient's age and gender; place of event, cause, circumstances and severity of the intoxication; as well as signs and symptoms of the muscarinic, nicotinic and neurological effects. Results: seventy patients (average age: 25±19.97 formed the study's population. It was observed that 77.14% of them suffered carbamate intoxication. However, organophosphate intoxications were more severe, with 68.75% of patients presenting moderate to severe forms. Suicide attempt was the leading cause of poisoning, with 62 cases (88.57% of total. Atropine administration was an effective therapeutic approach for treating signs and symptoms, which included sialorrhea (p=0.0006, nausea (p=0. 0029 and emesis (p lt0.0001. The use of activated charcoal was shown effective, both in combating the signs and symptoms presented by both patient groups (p <0.0001. Conclusion: it is concluded that the use of atropine and activated charcoal is highly effective to treat the signs and symptoms developed by patients presenting acute exogenous intoxication by carbamates or organophosphates.

  6. Deconvolution Method for Determination of the Nitrogen Content in Cellulose Carbamates

    Institute of Scientific and Technical Information of China (English)


    Cellulose carbamates (CC) were synthesized with microcrystalline cellulose as raw materials. The Fourier transform infrared spectra of CC with different nitrogen content were recorded. The accurate results of the nitrogen content for CC can be obtained by using the deconvolution method when the nitrogen content is less than 3.5%. The relationship between the nitrogen content and the absorption intensity ratio of the corresponding separated absorption peaks in FTIR spectra has been expressed by an equation precisely.

  7. [Thermal test of reactive hyperemia: a propos of an objective study of pyridinol carbamate]. (United States)

    Lauliac, M


    The thermal test of reactive hyperhemia (TTHR) gives a global and reliable appreciation of the cutaneous microcirculation, the importance of which is well known. In this study, sixty-one subjects were treated for from one month to one year with pyridinol-carbamate. The TTHR was modified in seventy-nine per cent of the cases, showing a considerable and lasting improvement. The clinical symptoms followed a comparable evolution.

  8. Preparation of sintered silver nanosheets by coating technique using silver carbamate complex

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Hee-Yong; Cha, Jae-Ryung; Gong, Myoung-Seon, E-mail:


    This study describes a coating technique approach for large-scale preparation of sintered silver nanosheets whose lateral dimensions were controlled in the thickness range of 50–65 nm. These procedures involved coating water-soluble poly (vinyl alcohol) (PVA) and silver 2-ethylhexylcarbamate (Ag-EHC), as well as thermal reduction of a silver precursor by heating at 150 °C, followed by dissolving away the PVA layer with alcoholic water. When the silver carbamate layer on the PVA layer was heated to 150 °C, the silver carbamate layer was thermally reduced and directed to grow into uniform sintered nanosheets with aspect ratios as high as 1000. The multi-stacked PVA/Ag structures and sintered silver nanosheets were confirmed by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Measurements of the conductive property at room temperature indicated that these nanosheets were electrically continuous with a resistivity of approximately 7.3 × 10{sup −6} Ω cm. - Highlights: • A coating technique is used to make sintered Ag nanosheets. • PVA and silver carbamate act as a separation layer and a silver precursor. • The Ag nanosheets have thickness width 50–60 nm and width up to hundred μm. • The Ag nanosheets showed a resistivity of ca. 7.3 × 10{sup −6} Ω cm.

  9. Novel cinchona carbamate selectors with complementary enantioseparation characteristics for N-acylated amino acids. (United States)

    Krawinkler, Karl Heinz; Maier, Norbert M; Ungaro, Rocco; Sansone, Francesco; Casnati, Alessandro; Lindner, Wolfgang


    The synthesis and chromatographic evaluation of the enantiomer separation capabilities of covalently immobilized calix[4]arene-cinchona carbamate hybrid type receptors derived from quinine (QN) and its corresponding C9-epimer (eQN) in different solvents are reported. The receptors display complementary enantiomer separation profiles in terms of elution order, chiral substrate specificity, and mobile phase characteristics, indicating the existence of two distinct chiral recognition mechanisms. The QN-derived receptor binds the (S)-enantiomers of N-acylated amino acids more strongly, shows preferential recognition of open-chained amino acids, and superior enantioselectivity in polar media such as methanol/acetic acid. In contrast, the eQN congener preferentially recognizes the corresponding (R)-enantiomers, displays good enantioselectivity (alpha up to 1.74) for cyclic amino acids, and enhanced stereodiscriminating properties in apolar mobile phases, e.g., chloroform/acetic acid. A comparison of the enantiomer separation profiles with those of the corresponding QN and eQN tert-butyl carbamate congeners indicates no significant level of cooperativity between the calix[4]arene module and the cinchona units in terms of overall chiral recognition, most probably as a consequence of residual conformational flexibility of the calixarene module and the carbamate linkage.

  10. Discovery of Highly Selective and Nanomolar Carbamate-Based Butyrylcholinesterase Inhibitors by Rational Investigation into Their Inhibition Mode. (United States)

    Sawatzky, Edgar; Wehle, Sarah; Kling, Beata; Wendrich, Jan; Bringmann, Gerhard; Sotriffer, Christoph A; Heilmann, Jörg; Decker, Michael


    Butyrylcholinesterase (BChE) is a promising target for the treatment of later stage cognitive decline in Alzheimer's disease. A set of pseudo-irreversible BChE inhibitors with high selectivity over hAChE was synthesized based on carbamates attached to tetrahydroquinazoline scaffolds with the 2-thiophenyl compound 2p as the most potent inhibitor of eqBChE (KC = 14.3 nM) and also of hBChE (KC = 19.7 nM). The inhibitors transfer the carbamate moiety onto the active site under release of the phenolic tetrahydroquinazoline scaffolds that themselves act as neuroprotectants. By combination of kinetic data with molecular docking studies, a plausible binding model was probed describing how the tetrahydroquinazoline scaffold guides the carbamate into a close position to the active site. The model explains the influence of the carrier scaffold onto the affinity of an inhibitor just before carbamate transfer. This strategy can be used to utilize the binding mode of other carbamate-based inhibitors.

  11. Combating highly resistant emerging pathogen Mycobacterium abscessus and Mycobacterium tuberculosis with novel salicylanilide esters and carbamates. (United States)

    Baranyai, Zsuzsa; Krátký, Martin; Vinšová, Jarmila; Szabó, Nóra; Senoner, Zsuzsanna; Horváti, Kata; Stolaříková, Jiřina; Dávid, Sándor; Bősze, Szilvia


    In the Mycobacterium genus over one hundred species are already described and new ones are periodically reported. Species that form colonies in a week are classified as rapid growers, those requiring longer periods (up to three months) are the mostly pathogenic slow growers. More recently, new emerging species have been identified to lengthen the list, all rapid growers. Of these, Mycobacterium abscessus is also an intracellular pathogen and it is the most chemotherapy-resistant rapid-growing mycobacterium. In addition, the cases of multidrug-resistant Mycobacterium tuberculosis infection are also increasing. Therefore there is an urgent need to find new active molecules against these threatening strains. Based on previous results, a series of salicylanilides, salicylanilide 5-chloropyrazinoates and carbamates was designed, synthesized and characterised. The compounds were evaluated for their in vitro activity on M. abscessus, susceptible M. tuberculosis H37Rv, multidrug-resistant (MDR) M. tuberculosis MDR A8, M. tuberculosis MDR 9449/2006 and on the extremely-resistant Praha 131 (XDR) strains. All derivatives exhibited a significant activity with minimum inhibitory concentrations (MICs) in the low micromolar range. Eight salicylanilide carbamates and two salicylanilide esters exhibited an excellent in vitro activity on M. abscessus with MICs from 0.2 to 2.1 μM, thus being more effective than ciprofloxacin and gentamicin. This finding is potentially promising, particularly, as M. abscessus is a threateningly chemotherapy-resistant species. M. tuberculosis H37Rv was inhibited with MICs from 0.2 μM, and eleven compounds have lower MICs than isoniazid. Salicylanilide esters and carbamates were found that they were effective also on MDR and XDR M. tuberculosis strains with MICs ≥1.0 μM. The in vitro cytotoxicity (IC50) was also determined on human MonoMac-6 cells, and selectivity index (SI) of the compounds was established. In general, salicylanilide

  12. Synthesis and evaluation of benzimidazole carbamates bearing indole moieties for antiproliferative and antitubulin activities. (United States)

    Guan, Qi; Han, Chunming; Zuo, Daiying; Zhai, Min'an; Li, Zengqiang; Zhang, Qian; Zhai, Yanpeng; Jiang, Xuewei; Bao, Kai; Wu, Yingliang; Zhang, Weige


    A series of novel benzimidazole carbamates bearing indole moieties with sulphur or selenium atoms connecting the aromatic rings were synthesised and evaluated for their antiproliferative activities against three human cancer cell lines (SGC-7901, A-549 and HT-1080) using an MTT assay. Compounds 10a, 10b, 7a, 7b and 7f showed significant activities against these cell lines. The most potent compound in this series, 10a, was selected to investigate its antitumour mechanism. In addition, molecular docking studies suggested that compound 10a interacts very closely with the nocodazole docking pose through hydrogen bonds at the colchicine binding site of tubulin.

  13. 76 FR 34147 - Land Disposal Restrictions: Revision of the Treatment Standards for Carbamate Wastes (United States)


    ... production of carbamates and carbamoyl oximes. Acetophenone...... 98-86-2 0.010 9.7 Aniline 62-53-3 0.81 14...-3 0.059 5.6 Phenol 108-95-2 0.039 6.2 Pyridine 110-86-1 0.014 16 Toluene 108-88-3 0.080 10... CARBN Methylene chloride 75-09-2 0.089 30 Methylethyl ketone 78-93-3 0.28 36 Pyridine 110-86-1 0.014...

  14. Simple, specific analysis of organophosphorus and carbamate pesticides in sediments using column extraction and gas chromatography (United States)

    Belisle, A.A.; Swineford, D.M.


    A simple, specific procedure was developed for the analysis of organophosphorus and carbamate pesticides in sediment. The wet soil was mixed with anhydrous sodium sulfate to bind water and the residues were column extracted in acetone:methylene chloride (1:l,v/v). Coextracted water was removed by additional sodium sulfate packed below the sample mixture. The eluate was concentrated and analyzed directly by capillary gas chromatography using phosphorus and nitrogen specific detectors. Recoveries averaged 93 % for sediments extracted shortly after spiking, but decreased significantly as the samples aged.

  15. Equilibrium constant for carbamate formation from monoethanolamine and its relationship with temperature

    Energy Technology Data Exchange (ETDEWEB)

    Aroua, M.K.; Benamor, A.; Haji-Sulaiman, M.Z. [Univ. of Malaya, Kuala Lumpur (Malaysia). Dept. of Chemical Engineering


    Removal of acid gases such as CO{sub 2} and H{sub 2}S using aqueous solutions of alkanolamines is an industrially important process. The equilibrium constant for the formation of carbamate from monoethanolamine was evaluated at various temperatures of 298, 308, 318, and 328 K and ionic strengths up to 1.7 M. From the plot of log{sub 10} K versus I{sup 0.5}, the variation of the thermodynamical constant with temperature follows the relationship log{sub 10} K{sub 1} = {minus}0.934 + (0.671 {times} 10{sup 3})K/T.

  16. Formation of Carbamate Anions by the Gas-phase Reaction of Anilide Ions with CO2. (United States)

    Liu, Chongming; Nishshanka, Upul; Attygalle, Athula B


    The anilide anion (m/z 92) generated directly from aniline, or indirectly as a fragmentation product of deprotonated acetanilide, captures CO2 readily to form the carbamate anion (m/z 136) in the collision cell, when CO2 is used as the collision gas in a tandem-quadrupole mass spectrometer. The gas-phase affinity of the anilide ion to CO2 is significantly higher than that of the phenoxide anion (m/z 93), which adds to CO2 only very sluggishly. Our results suggest that the efficacy of CO2 capture depends on the natural charge density on the nitrogen atom, and relative nucleophilicity of the anilide anion. Generally, conjugate bases generated from aniline derivatives with proton affinities (PA) less than 350 kcal/mol do not tend to add CO2 to form gaseous carbamate ions. For example, the anion generated from p-methoxyaniline (PA = 367 kcal/mol) reacts significantly faster than that obtained from p-nitroaniline (PA = 343 kcal/mol). Although deprotonated p-aminobenzoic acid adds very poorly because the negative charge is now located primarily on the carboxylate group, it reacts more efficiently with CO2 if the carboxyl group is esterified. Moreover, mixture of CO2 and He as the collision gas was found to afford more efficient adduct formation than CO2 alone, or as mixtures made with nitrogen or argon, because helium acts as an effective "cooling" gas and reduces the internal energy of reactant ions.

  17. Confirmed organophosphorus and carbamate pesticide poisonings in South African wildlife (2009–2014

    Directory of Open Access Journals (Sweden)

    Christo J. Botha


    Full Text Available During a six-year period (from January 2009 to December 2014, specimens collected from 344 cases of suspected organophosphorus and carbamate pesticide poisonings in wildlife, including birds, were submitted to the Toxicology Laboratory (ARC-OVI for analysis. A positive diagnosis was made in 135 (39% of these cases. The majority of cases were from birds, which included Cape vultures (Gyps coprotheres and African white-backed vultures (Gyps africanus and bateleur eagles (Terathopius ecaudatus. In one incident 49 vultures were killed when a farmer intentionally laced carcasses with carbofuran in an attempt to control jackal predation. There were 22 incidents of poisoning in helmeted guineafowl (Numida meleagris. On nine different occasions blue cranes (Anthropoides paradiseus were poisoned, in one incident 14 birds were reported to have been killed. Over the period of investigation, there were 20 cases of poisoning involving mammalian species, the majority being vervet monkeys (Chlorocebus pygerythrus. The carbamate pesticides were responsible for 57 incidents of poisoning. Aldicarb, carbofuran and methomyl were detected in 26, 18 and 12 cases respectively. The majority of organophosphorus pesticide poisonings were caused by diazinon (n = 19, monocrotophos (n = 13 and methamidophos (n = 10.

  18. Carbamate-linked cationic lipids with different hydrocarbon chains for gene delivery. (United States)

    Shi, Jia; Yu, Shijun; Zhu, Jie; Zhi, Defu; Zhao, Yinan; Cui, Shaohui; Zhang, Shubiao


    A series of carbamate-linked cationic lipids containing saturated or unsaturated hydrocarbon chains and quaternary ammonium head were designed and synthesized. After recrystallization, carbamate-linked cationic lipids with high purity (over 95%) were obtained. The structures of these lipids were proved by IR spectrum, HR-ESI-MS, HPLC, (1)H NMR and (13)C NMR. The liposomes were prepared by using these cationic lipids and neutral lipid DOPE. Particle size and zeta-potential were studied to show that they were suitable for gene transfection. The DNA-bonding ability of C12:0, C14:0 and C18:1 cationic liposomes was much better than others. The results of transfection showed that hydrophobic chains of these lipids have great effects on their transfection activity. The lipids bearing C12:0, C14:0 saturated chains or C18:1 unsaturated chain showed relatively higher transfection efficiency and lower cytotoxicity. So these cationic lipids could be used as non-viral gene carriers for further studies.

  19. Treatment of Toxocara canis infections in mice with liposome-incorporated benzimidazole carbamates and immunomodulator glucan. (United States)

    Hrckova, G; Velebný, S


    Benzimidazole carbamates (mebendazole, albendazole and fenbendazole) are the most commonly used anthelmintic drugs for the treatment of larval toxocariasis (Toxocara canis) in paratenic hosts. However, the bioavailability of these drugs for tissues is very low due to their extremely low solubility, resulting in the administration of relatively high doses over a long period. To overcome this problem, neutral, negatively or positively charged and stabilized liposome drug carriers were examined in the chronic phase of T. canis infections in mice each orally inoculated with 1000 eggs. Moreover, liposomized albendazole and fenbendazole were co-administered with liposomized immunomodulator glucan. The highest efficacy of both drugs, evaluated 4 weeks after treatment, was recorded after their subcutaneous administration (ten doses of 25 mg kg(-1)) in stabilized liposomes and intramuscular co-administration of liposomized glucan (two doses of 5 mg kg(-1)). Fenbendazole was more effective in muscles (91.5%) whereas albendazole was more effective in the brain (92.2%). Liposomes with incorporated benzimidazole carbamate anthelmintics provide sustained drug-release reservoirs and can considerably enhance drug efficacy. Moreover, despite suppression by T. canis antigens, stimulation of the immune system by the immunomodulator glucan potentiates the effects of these antiparasitic drugs.

  20. Blackberry subjected to in vitro gastrointestinal digestion affords protection against Ethyl Carbamate-induced cytotoxicity. (United States)

    Chen, Wei; Xu, Yang; Zhang, Lingxia; Su, Hongming; Zheng, Xiaodong


    Ethyl Carbamate (EC) was detected in many fermented foods. Previous studies indicated that frequent exposure to ethyl carbamate may increase the risk to suffer from cancers. Blackberry is rich in polyphenols and possesses potent antioxidant activity. This study aims to investigate the protective effect of blackberry homogenates produced before (BH) and after in vitro simulated gastrointestinal digestion (BD) on EC-induced toxicity in Caco-2 cells. Our results showed that blackberry homogenates after digestion (BD) was more effective than that before digestion (BH) in ameliorating EC-induced toxicity in Caco-2 cells. Further investigation revealed that BD remarkably attenuated EC-induced toxicity through restoring mitochondrial function, inhibiting glutathione depletion and decreasing overproduction of intracellular reactive oxygen species. Additionally, LC-MS result implied that the better protective capacity of BD may be related to the increased content of two anthocyanins (cyanidin-3-glucoside and cyanidin-3-dioxalyglucoside). Overall, the present study may give implication to prevent EC-induced health problem.

  1. Carbamate and Pyrethroid Resistance in the Akron Strain of Anopheles gambiae (United States)

    Mutunga, James M.; Anderson, Troy D.; Craft, Derek T.; Gross, Aaron D.; Swale, Daniel R.; Tong, Fan; Wong, Dawn M.; Carlier, Paul R.; Bloomquist, Jeffrey R.


    Insecticide resistance in the malaria vector, Anopheles gambiae is a serious problem, epitomized by the multi-resistant Akron strain, originally isolated in the country of Benin. Here we report resistance in this strain to pyrethroids and DDT (13-fold to 35-fold compared to the susceptible G3 strain), but surprisingly little resistance to etofenprox, a compound sometimes described as a “pseudo-pyrethroid.” There was also strong resistance to topically-applied commercial carbamates (45-fold to 81-fold), except for the oximes aldicarb and methomyl. Biochemical assays showed enhanced cytochrome P450 monooxygenase and carboxylesterase activity, but not that of glutathione-S-transferase. A series of substituted α,α,α,-trifluoroacetophenone oxime methylcarbamates were evaluated for enzyme inhibition potency and toxicity against G3 and Akron mosquitoes. The compound bearing an unsubstituted phenyl ring showed the greatest toxicity to mosquitoes of both strains. Low cross resistance in Akron was retained by all analogs in the series. Kinetic analysis of acetylcholinesterase activity and its inhibition by insecticides in the G3 strain showed inactivation rate constants greater than that of propoxur, and against Akron enzyme inactivation rate constants similar to that of aldicarb. However, inactivation rate constants against recombinant human AChE were essentially identical to that of the G3 strain. Thus, the acetophenone oxime carbamates described here, though potent insecticides that control resistant Akron mosquitoes, require further structural modification to attain acceptable selectivity and human safety. PMID:26047119

  2. Synthesis and fungicidal activity of aryl carbamic acid-5-aryl-2-furanmethyl ester. (United States)

    Li, Ying; Li, Bao-Ju; Ling, Yun; Miao, Hong-Jian; Shi, Yan-Xia; Yang, Xin-Ling


    Chitin, a major structural component of insect cuticle and fungus cell wall but absent in plants and vertebrates, is regarded as a safe and selective target for pest control agents. Chitin synthesis inhibitors (CSIs) have been well-known as insect growth regulators (IGRs) but rarely found as fungicides in agriculture. To find novel CSIs with good activity, benzoylphenylurea, a typical kind of CSIs, was chosen as the lead compound and 26 novel aryl carbamic acid-5-aryl-2-furanmethyl esters were designed by converting the urea linkages of benzoylphenylureas to carbamic acid esters and changing the aniline parts into furanmethyl groups. The title compounds were synthesized and their structures confirmed by IR, (1)H NMR, and elemental analysis. Preliminary insecticidal and fungicidal bioassays were carried out. The results indicated that the title compounds had no insecticidal effect on Culex pipiens pallens and Plutella xylostella Linnaeus , but most compounds exhibited good fungicidal activities against Corynespora cassiicola , Thanatephorus cucumeris , Botrytis cinerea , and Fusarium oxysporum . In particular, compounds V-4, V-6, V-7, and V-8 showed better activities against the four strains than those of the commercialized fungicides. The morphologic result suggested that compound V-21 had disturbed the cell wall formation of C. cassiicola. The results indicated that modification on the urea linkage of benzoylphenylurea was an effective way to discover new candidates for fungicides.

  3. Synthesis and Evaluation as Prodrugs of Hydrophilic Carbamate Ester Analogues of Resveratrol. (United States)

    Azzolini, Michele; Mattarei, Andrea; La Spina, Martina; Marotta, Ester; Zoratti, Mario; Paradisi, Cristina; Biasutto, Lucia


    Resveratrol (3,5,4'-trihydroxy-trans-stilbene) is an unfulfilled promise for health care: its exploitation is hindered by rapid conjugative metabolism in enterocytes and hepatocytes; low water solubility is a serious practical problem. To advantageously modify the physicochemical properties of the compound we have developed prodrugs in which all or part of the hydroxyl groups are linked via an N-monosubstituted carbamate ester bond to promoieties derived from glycerol or galactose, conferring higher water solubility. Kinetic studies of hydrolysis in aqueous solutions and in blood indicated that regeneration of resveratrol takes place in an appropriate time frame for delivery via oral administration. Despite their hydrophilicity some of the synthesized compounds were absorbed in the gastrointestinal tract of rats. In these cases the species found in blood after administration of a bolus consisted mainly of partially deprotected resveratrol derivatives and of the products of their glucuronidation, thus providing proof-of-principle evidence of behavior as prodrugs. The soluble compounds largely reached the lower intestinal tract. Upon administration of resveratrol, the major species found in this region was dihydroresveratrol, produced by enzymes of the intestinal flora. In experiments with a fully protected (trisubstituted) deoxygalactose containing prodrug, the major species were the prodrug itself and partially deprotected derivatives, along with small amounts of dihydroresveratrol. We conclude that the N-monosubstituted carbamate moiety is suitable for use in prodrugs of polyphenols.

  4. Synthesis and biological activity of beta-glucuronyl carbamate-based prodrugs of paclitaxel as potential candidates for ADEPT

    NARCIS (Netherlands)

    deBont, DBA; Leenders, RGG; Haisma, HJ; vanderMeulenMuileman, [No Value; Scheeren, HW


    The syntheses of prodrugs of paclitaxel, which can be used in ADEPT in order to target paclitaxel towards tumor cells, are described. The prodrugs 1 and 2a,b consist of a spacer molecule connected via a carbamate linkage to a beta-glucuronic acid. The spacer molecule is also connected via an ester l

  5. Lithium choreography: intramolecular arylations of carbamate-stabilised carbanions and their mechanisms probed by in situ IR spectroscopy and DFT calculations. (United States)

    Fournier, Anne M; Nichols, Christopher J; Vincent, Mark A; Hillier, Ian H; Clayden, Jonathan


    Deprotonation of O-allyl, O-propargyl or O-benzyl carbamates in the presence of a lithium counterion leads to carbamate-stabilised organolithium compounds that may be quenched with electrophiles. We now report that when the allylic, propargylic or benzylic carbamate bears an N-aryl substituent, an aryl migration takes place, leading to stereochemical inversion and C-arylation of the carbamate α to oxygen. The aryl migration is an intramolecular S(N) Ar reaction, despite the lack of anion-stabilising aryl substituents. Our in situ IR studies reveal a number of intermediates along the rearrangement pathway, including a "pre-lithiation complex," the deprotonated carbamate, the rearranged anion, and the final arylated carbamate. No evidence was obtained for a dearomatised intermediate during the aryl migration. DFT calculations predict that during the reaction the solvated Li cation moves from the carbanion centre, thus freeing its lone pair for nucleophilic attack on the remote phenyl ring. This charge separation leads to several alternative conformations. The one having Li(+) bound to the carbamate oxygen gives rise to the lowest-energy transition structure, and also leads to inversion of the configuration. In agreement with the IR studies, the DFT calculations fail to locate a dearomatised intermediate.

  6. Poisoning of cats and dogs by the carbamate pesticides aldicarb and carbofuran. (United States)

    de Siqueira, Adriana; Salvagni, Fernanda Auciello; Yoshida, Alberto Soiti; Gonçalves-Junior, Vagner; Calefi, Atilio Sersun; Fukushima, André Rinaldi; Spinosa, Helenice de Souza; Maiorka, Paulo César


    The intentional and accidental poisoning of animals and people is a threat to public health and safety worldwide. Necropsies and histopathological examinations of 26 cats and 10 dogs poisoned by the carbamates aldicarb and carbofuran, confirmed by thin layer chromatography (TLC) and high performance liquid chromatography with diode-array detector (HPLC-DAD) were analysed, with variable post mortem interval and conservation of the carcass. Biological matrices were collected for toxicological and histopathological analyses. High performance liquid chromatography with diode-array detector (HPLC-DAD) was utilized to detect aldicarb and its metabolites, aldicarb sulphoxide and aldicarb sulphone, and carbofuran. The variable post mortem interval and the method of conservation of the carcass may be harmful to toxicological, necroscopic and histopathological analyses, that should be performed in order to provide reliable evidences to investigate possible poisoning of animals, which is cruel crime, and are usually linked to domestic or social conflict.

  7. A general method for tritium labelling of benzimidazole carbamates by catalytic exchange in dioxane solutions

    Energy Technology Data Exchange (ETDEWEB)

    Lacey, E. (Commonwealth Scientific and Industrial Research Organization, Glebe, NSW (Australia). Div. of Animal Health, McMaster Lab.); Dawson, M. (Sydney Univ. (Australia). Dept. of Pharmacy); Long, M.A.; Than, C. (New South Wales Univ., Kensington (Australia). School of Chemistry)


    Benzimidazole carbamates (BZCs) act as inhibitors of the tubulin-microtubule equilibria in eukaryotic organisms. Recently drug resistance to this class of compounds in helminth parasites has been shown to be due to a reduced ability of resistant tubulin to bind BZCs. In order to quantitate the nature of the tubulin-BZC interaction a general method for the specific tritium labelling of BZCs has been developed. The BZCs: mebendazole, oxfendazole, parbendazole, oxibendazole, albendazole and fenbendazole were labelled by catalytic exchange using palladium on calcium carbonate in pure dioxane at 60{sup 0}C under tritium gas. The position of label incorporation for tritiated albendazole was determined by tritium-NMR as the 4-position of benzimadazole nucleus. The yields for individual BZCs varied from 8 to 68% for a range of specific activity of 0.44 to 13.4 Ci/mmole. (author).

  8. Carbamate derivatives and sesquiterpenoids from the South China Sea gorgonian Melitodes squamata

    Directory of Open Access Journals (Sweden)

    Li-Si Huang


    Full Text Available Five carbamate derivatives, obtucarbamates C and D (1, 2, dimethyl ((carbonylbis(azanediylbis(2-methyl-5,1-phenylenedicarbamate (3, obtucarbamates A and B (4, 5, and four aromadendrane-type sesquiterpenoids, (+-4β-N-methenetauryl-10β-methoxy-1β,5α,6β,7β-aromadendrane (6, (−-4β-N-methenetauryl-10β-methoxy-1β,5β,6α,7α-aromadendrane (7, (−-4α,10β-aromadendranediol (8, (+-4β,10β-aromadendranediol (9 were obtained from the South China Sea gorgonian coral Melitodes squamata Nutting. Compounds 1, 2, 6, and 7 were new, and their structures were established by spectroscopic analyses. Compounds 6 and 7 contained a taurine group that was rarely found in marine natural compounds, and 7 showed moderate antibacterial activity. The possible biosynthesis routes of 1–5 were conjectured.

  9. [Plasma cholesterol determination in birds--a diagnostic tool for detection of organophosphate and carbamate intoxication]. (United States)

    Kiesau, B; Kummerfeld, N


    An investigation was done on the clinical usefulness of the dry chemistry analyzer Vitros DT 60 II for determination of avian plasma cholinesterase. The analytical reliability of the method, evaluated by precision and accuracy, proved to be high for plasma of numerous pet and wild birds. Values of normal plasma-cholinesterase activity were established for different psittacine and European wild birds. Significant differences in physiologic plasma-cholinesterase activity were noted between closely related species as well as between juvenile and adult birds. These findings emphasize the necessity to use control values of the same species and age group for comparison. Dry chemistry plasma-cholinesterase determination can be used as a diagnostic tool for detection of organophosphate and carbamate poisonings in the majority of investigated birds.

  10. Children poisoning by carbamate: a descriptive study - doi:10.5020/18061230.2004.p193

    Directory of Open Access Journals (Sweden)

    Luiza Jane Eyre de Souza Vieira


    Full Text Available The study had as its aim to characterize the children under 5 years old, attended with exogenous poisoning by carbamate (popularly called “chumbinho” – “small shot” at an emergency hospital in Fortaleza and to relate the signs and symptoms detected in this type of poisoning. It concerned a descriptive study, with a sample of 65 children attended during the period of 1998 to 2000, in Fortaleza, Ceará. It was noticed that the most affected age group was of those with 1 to 3 years old, not being verified any significant difference between sexes. The most evident signs and symptoms were myosis, vomits, profuse perspiration and sialorrhea and the predominant treatment was the use of active coal. It is concluded, therefore, that there is a need of putting into effect the health education, calling the society’s attention to the risks of the inadequate “chumbinho” use in the domiciliar environment.

  11. Solubility improvement of an anthelmintic benzimidazole carbamate by association with dendrimers

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, L.; Sigal, E.; Santo, M., E-mail: [Departamento de Fisica, Facultad de Ciencias Exactas Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto (Argentina); Otero, L.; Silber, J. J. [Departamento de Quimica. Facultad de Ciencias Exactas Fisicoquimicas y Naturales, Universidad Nacional de Rio Cuarto, Rio Cuarto (Argentina)


    The improvement of aqueous solubility of methyl (5-[propylthio]-1H-benzimidazole-2-yl) carbamate, albendazole (ABZ) using polyamidoamine (PAMAM) dendrimers as solubility enhancers was investigated. Full generation PAMAM dendrimers with amine terminal groups, (G3), with hydroxyl terminal groups (G3OH) and half generation PAMAM dendrimers with carboxylate terminal groups (G2.5 and G3.5), were chosen for this study. The nature of dendrimer-ABZ association was investigated by UV absorption, fluorescence emission measurements and by {sup 1}H-NMR spectroscopy. The results obtained show that these polymeric structures have the capacity to enhance the solubility of ABZ, both lipophilic and specific hydrogen bond interactions contributing to the guest-host association. Although all studied dendrimers have hydrophobic internal nanoenvironments with similar dimensions, their surfaces differ significantly and the nature and the localization of the interactions involved in ABZ-dendrimer association depend on the type of terminal groups. (author)

  12. From immunotoxicity to carcinogenicity: the effects of carbamate pesticides on the immune system. (United States)

    Dhouib, Ines; Jallouli, Manel; Annabi, Alya; Marzouki, Soumaya; Gharbi, Najoua; Elfazaa, Saloua; Lasram, Mohamed Montassar


    The immune system can be the target of many chemicals, with potentially severe adverse effects on the host's health. In the literature, carbamate (CM) pesticides have been implicated in the increasing prevalence of diseases associated with alterations of the immune response, such as hypersensitivity reactions, some autoimmune diseases and cancers. CMs may initiate, facilitate, or exacerbate pathological immune processes, resulting in immunotoxicity by induction of mutations in genes coding for immunoregulatory factors and modifying immune tolerance. In the present study, direct immunotoxicity, endocrine disruption and inhibition of esterases activities have been introduced as the main mechanisms of CMs-induced immune dysregulation. Moreover, the evidence on the relationship between CM pesticide exposure, dysregulation of the immune system and predisposition to different types of cancers, allergies, autoimmune and infectious diseases is criticized. In addition, in this review, we will discuss the relationship between immunotoxicity and cancer, and the advances made toward understanding the basis of cancer immune evasion.

  13. Anticonvulsant properties of histamine H3 receptor ligands belonging to N-substituted carbamates of imidazopropanol. (United States)

    Sadek, Bassem; Shehab, Safa; Więcek, Małgorzata; Subramanian, Dhanasekaran; Shafiullah, Mohamed; Kieć-Kononowicz, Katarzyna; Adem, Abdu


    Ligands targeting central histamine H3 receptors (H3Rs) for epilepsy might be a promising therapeutic approach. Therefore, the previously described and structurally strongly related imidazole-based derivatives belonging to carbamate class with high H3R in vitro affinity, in-vivo antagonist potency, and H3R selectivity profile were investigated on their anticonvulsant activity in maximal electroshock (MES)-induced and pentylenetetrazole (PTZ)-kindled seizure models in Wistar rats. The effects of systemic injection of H3R ligands 1-13 on MES-induced and PTZ-kindled seizures were screened and evaluated against the reference antiepileptic drug (AED) Phenytoin (PHT) and the standard histamine H3R inverse agonist/antagonist Thioperamide (THP) to determine their potential as new antiepileptic drugs. Following administration of the H3R ligands 1-13 (5, 10 and 15 mg/kg, ip) there was a significant dose dependent reduction in MES-induced seizure duration. The protective action observed for the pentenyl carbamate derivative 4, the most protective H3R ligand among 1-13, was significantly higher (P histamine (RAMH) (10mg/kg), or with the CNS penetrant H1R antagonist Pyrilamine (PYR) (10mg/kg). In addition, subeffective dose of H3R ligand 4 (5mg/kg, ip) significantly potentiated the protective action in rats pretreated with PHT (5mg/kg, ip), a dose without appreciable protective effect when given alone. In contrast, pretreatment with H3R ligand 4 (10mg/kg ip) failed to modify PTZ-kindled convulsion, whereas the reference drug PHT was found to fully protect PTZ-induced seizure. These results indicate that some of the investigated imidazole-based H3R ligands 1-13 may be of future therapeutic value in epilepsy.

  14. Novel Cholinesterase Inhibitors Based on O-Aromatic N,N-Disubstituted Carbamates and Thiocarbamates

    Directory of Open Access Journals (Sweden)

    Martin Krátký


    Full Text Available Based on the presence of carbamoyl moiety, twenty salicylanilide N,N-disubstituted (thiocarbamates were investigated using Ellman’s method for their ability to inhibit acetylcholinesterase (AChE and butyrylcholinesterase (BChE. O-Aromatic (thiocarbamates exhibited weak to moderate inhibition of both cholinesterases with IC50 values within the range of 1.60 to 311.0 µM. IC50 values for BChE were mostly lower than those obtained for AChE; four derivatives showed distinct selectivity for BChE. All of the (thiocarbamates produced a stronger inhibition of AChE than rivastigmine, and five of them inhibited BChE more effectively than both established drugs rivastigmine and galantamine. In general, 5-chloro-2-hydroxy-N-[4-(trifluoromethyl-phenyl]benzamide, 2-hydroxy-N-phenylbenzamide as well as N-methyl-N-phenyl carbamate derivatives led to the more potent inhibition. O-{4-Chloro-2-[(4-chlorophenylcarbamoyl]phenyl} dimethylcarbamothioate was identified as the most effective AChE inhibitor (IC50 = 38.98 µM, while 2-(phenylcarbamoylphenyl diphenylcarbamate produced the lowest IC50 value for BChE (1.60 µM. Results from molecular docking studies suggest that carbamate compounds, especially N,N-diphenyl substituted representatives with considerable portion of aromatic moieties may work as non-covalent inhibitors displaying many interactions at peripheral anionic sites of both enzymes. Mild cytotoxicity for HepG2 cells and consequent satisfactory calculated selectivity indexes qualify several derivatives for further optimization.

  15. Kinetic characterization of arginine deiminase and carbamate kinase from Streptococcus pyogenes M49. (United States)

    Hering, Silvio; Sieg, Antje; Kreikemeyer, Bernd; Fiedler, Tomas


    Streptococcus pyogenes (group A Streptococcus, GAS) is an important human pathogen causing mild superficial infections of skin and mucous membranes, but also life-threatening systemic diseases. S. pyogenes and other prokaryotic organisms use the arginine deiminase system (ADS) for survival in acidic environments. In this study, the arginine deiminase (AD), and carbamate kinase (CK) from S. pyogenes M49 strain 591 were heterologously expressed in Escherichia coli DH5α, purified, and kinetically characterized. AD and CK from S. pyogenes M49 share high amino acid sequence similarity with the respective enzymes from Lactococcus lactis subsp. lactis IL1403 (45.6% and 53.5% identical amino acids) and Enterococcus faecalis V583 (66.8% and 66.8% identical amino acids). We found that the arginine deiminase of S. pyogenes is not allosterically regulated by the intermediates and products of the arginine degradation (e.g., ATP, citrulline, carbamoyl phosphate). The Km and Vmax values for arginine were 1.13±0.12mM (mean±SD) and 1.51±0.07μmol/min/mg protein. The carbamate kinase is inhibited by ATP but unaffected by arginine and citrulline. The Km and Vmax values for ADP were 0.72±0.08mM and 1.10±0.10μmol/min/mg protein and the Km for carbamoyl phosphate was 0.65±0.07mM. The optimum pH and temperature for both enzymes were 6.5 and 37°C, respectively.

  16. Structural Basis for Inactivation of Giardia lamblia Carbamate Kinase by Disulfiram* (United States)

    Galkin, Andrey; Kulakova, Liudmila; Lim, Kap; Chen, Catherine Z.; Zheng, Wei; Turko, Illarion V.; Herzberg, Osnat


    Carbamate kinase from Giardia lamblia is an essential enzyme for the survival of the organism. The enzyme catalyzes the final step in the arginine dihydrolase pathway converting ADP and carbamoyl phosphate to ATP and carbamate. We previously reported that disulfiram, a drug used to treat chronic alcoholism, inhibits G. lamblia CK and kills G. lamblia trophozoites in vitro at submicromolar IC50 values. Here, we examine the structural basis for G. lamblia CK inhibition of disulfiram and its analog, thiram, their activities against both metronidazole-susceptible and metronidazole-resistant G. lamblia isolates, and their efficacy in a mouse model of giardiasis. The crystal structure of G. lamblia CK soaked with disulfiram revealed that the compound thiocarbamoylated Cys-242, a residue located at the edge of the active site. The modified Cys-242 prevents a conformational transition of a loop adjacent to the ADP/ATP binding site, which is required for the stacking of Tyr-245 side chain against the adenine moiety, an interaction seen in the structure of G. lamblia CK in complex with AMP-PNP. Mass spectrometry coupled with trypsin digestion confirmed the selective covalent thiocarbamoylation of Cys-242 in solution. The Giardia viability studies in the metronidazole-resistant strain and the G. lamblia CK irreversible inactivation mechanism show that the thiuram compounds can circumvent the resistance mechanism that renders metronidazole ineffectiveness in drug resistance cases of giardiasis. Together, the studies suggest that G. lamblia CK is an attractive drug target for development of novel antigiardial therapies and that disulfiram, an FDA-approved drug, is a promising candidate for drug repurposing. PMID:24558036

  17. Structural basis for inactivation of Giardia lamblia carbamate kinase by disulfiram. (United States)

    Galkin, Andrey; Kulakova, Liudmila; Lim, Kap; Chen, Catherine Z; Zheng, Wei; Turko, Illarion V; Herzberg, Osnat


    Carbamate kinase from Giardia lamblia is an essential enzyme for the survival of the organism. The enzyme catalyzes the final step in the arginine dihydrolase pathway converting ADP and carbamoyl phosphate to ATP and carbamate. We previously reported that disulfiram, a drug used to treat chronic alcoholism, inhibits G. lamblia CK and kills G. lamblia trophozoites in vitro at submicromolar IC50 values. Here, we examine the structural basis for G. lamblia CK inhibition of disulfiram and its analog, thiram, their activities against both metronidazole-susceptible and metronidazole-resistant G. lamblia isolates, and their efficacy in a mouse model of giardiasis. The crystal structure of G. lamblia CK soaked with disulfiram revealed that the compound thiocarbamoylated Cys-242, a residue located at the edge of the active site. The modified Cys-242 prevents a conformational transition of a loop adjacent to the ADP/ATP binding site, which is required for the stacking of Tyr-245 side chain against the adenine moiety, an interaction seen in the structure of G. lamblia CK in complex with AMP-PNP. Mass spectrometry coupled with trypsin digestion confirmed the selective covalent thiocarbamoylation of Cys-242 in solution. The Giardia viability studies in the metronidazole-resistant strain and the G. lamblia CK irreversible inactivation mechanism show that the thiuram compounds can circumvent the resistance mechanism that renders metronidazole ineffectiveness in drug resistance cases of giardiasis. Together, the studies suggest that G. lamblia CK is an attractive drug target for development of novel antigiardial therapies and that disulfiram, an FDA-approved drug, is a promising candidate for drug repurposing.

  18. Assessment of Organophosphate and Carbamate Pesticide Residues in Cigarette Tobacco with a Novel Cell Biosensor

    Directory of Open Access Journals (Sweden)

    Spiridon Kintzios


    Full Text Available The conventional analysis of pesticide residues in analytical commodities, such as tobacco and tobacco products is a labor intensive procedure, since it is necessary to cover a wide range of different chemicals, using a single procedure. Standard analysis methods include extensive sample pretreatment (with solvent extraction and partitioning phases and determination by GC and HPLC to achieve the necessary selectivity and sensitivity for the different classes of compounds under detection. As a consequence, current methods of analysis provide a limited sample capacity. In the present study, we report on the development of a novel cell biosensor for detecting organophosphate and carbamate pesticide residues in tobacco. The sensor is based on neuroblastoma N2a cells and the measurement of changes of the cell membrane potential, according to the working principle of the Bioelectric Recognition Assay (BERA. The presence of pesticide residues is detected by the degree of inhibition of acetylcholine esterase (AChE. The sensor instantly responded to both the organophoshate pesticide chlorpyriphos and the carbamate carbaryl in a concentration-dependent pattern, being able to detect one part per billion (1 ppb. Additionally, tobacco leaf samples (in blended dry form were analyzed with both the novel biosensor and conventional methods, according to a double-blind protocol. Pesticide residues in tobacco samples caused a considerable cell membrane hyperpolarization to neuroblastoma cells immobilized in the sensor, as indicated by the increase of the negative sensor potential, which was clearly distinguishable from the sensor’s response against pesticide-free control samples. The observed response was quite reproducible, with an average variation of +5,6%. Fluorescence microscopy observations showed that treatment of the cells with either chlorpyrifos or carbaryl was associated with increased [Ca2+]cyt . The novel biosensor offers fresh

  19. PPA-SiO2 Catalyzed Multi-component Synthesis of N-[α-(β-Hydroxy-α-naphthyl)(benzyl)]O-Alkyl Carbamate Derivatives

    Institute of Scientific and Technical Information of China (English)



    Silica-supported polyphosphoric acid (PPA-SiO2) was found to be an efficient catalyst for the multi-component condensation reaction of benzaldehydes,2-naphthol,and methyl/benzyl carbamate to afford the corresponding N-[α-(β-hydroxy-α-naphthyl)(benzyl)]O-alkyl carbamate derivatives in good to excellent yields.This new approach consistently has the advantage of short reaction time,high conversions,clean reaction profiles,and simple experimental and work-up procedures.

  20. Novel Preparation of Methoxy Carbamates of 1-Protected Indole- 3-methylamines as Precursor of Indole-3-methylamine

    Institute of Scientific and Technical Information of China (English)

    SONG,Hao; XIN,Jun-Guo; WANG,Yin; CHEN,Wei; YANG,Jun; QIN,Yong


    @@ Indole-3-methylamine (1) has been well demonstrated to be a very useful intermediate as a pharmaceutical building block and starting material for syntheses of phytoalexins.[1] The instability of indole-3-methylamine (1) has undoubtedly restricted its application in synthetic chemistry. Hofmann rearrangement that directly converts carboxamides to alky carbamates in the presence of alcohol required unexceptionally a strong base,[2] which devaluated the possible usefulness of Hofmann rearrangement in preparation of base sensitive amines, especially for the preparation of unstable indole-3-methylamine (1). Herein we would like to report a convenient method for the preparation of alkyl carbamates of 1-protected indole-3-methylamines (4) via the diacetoxyiodobenzene (DIB) promoted Hofmann rearrangement under neutral condition.

  1. Efficient hydrogenation of organic carbonates, carbamates and formates indicates alternative routes to methanol based on CO2 and CO. (United States)

    Balaraman, Ekambaram; Gunanathan, Chidambaram; Zhang, Jing; Shimon, Linda J W; Milstein, David


    Catalytic hydrogenation of organic carbonates, carbamates and formates is of significant interest both conceptually and practically, because these compounds can be produced from CO2 and CO, and their mild hydrogenation can provide alternative, mild approaches to the indirect hydrogenation of CO2 and CO to methanol, an important fuel and synthetic building block. Here, we report for the first time catalytic hydrogenation of organic carbonates to alcohols, and carbamates to alcohols and amines. Unprecedented homogeneously catalysed hydrogenation of organic formates to methanol has also been accomplished. The reactions are efficiently catalysed by dearomatized PNN Ru(II) pincer complexes derived from pyridine- and bipyridine-based tridentate ligands. These atom-economical reactions proceed under neutral, homogeneous conditions, at mild temperatures and under mild hydrogen pressures, and can operate in the absence of solvent with no generation of waste, representing the ultimate 'green' reactions. A possible mechanism involves metal-ligand cooperation by aromatization-dearomatization of the heteroaromatic pincer core.

  2. [A case of carbamate poisoning in which GCMS was useful to identify causal substance and to decide the appropriate treatment]. (United States)

    Kinoshita, H; Hirose, Y; Tanaka, T; Hori, Y; Nakajima, M; Fujisawa, M; Oseki, M


    We often have cases of insecticide poisoning where the patient is unconscious and the causal substances are unknown. We report an 83-year-old unconscious man who had apparently ingested several agricultural chemicals, possibly organophosphate or carbamate. According to his family, there were three kinds of containers of agricultural chemicals with their caps opened around him. When he was transferred to our hospital, he presented hypertension, hypersalivation, and muscle fasciculation. His pupils were markedly miotic. In order to identify the substances ingested we used a gas chromatographymass spectrometer (GCMS) using his gastric content. Within 30 minutes we were able to identify the causal substance as methomyl, one of the popular carbamates, thereby eliminating the need to use pralidoxime (PAM). GCMS makes it possible to identify unknown substances quickly and accurately and is therefore extremely useful in deciding the appropriate treatment.

  3. Solid-phase extraction of flavonoids in honey samples using carbamate-embedded triacontyl-modified silica sorbent. (United States)

    Liu, Houmei; Zhang, Mingliang; Guo, Yong; Qiu, Hongdeng


    In this study, carbamate-embedded triacontyl-modified silica (Sil-CBM-C30) is successfully prepared and used as an efficient sorbent for solid-phase extraction. The extraction performance of the resultant sorbent is evaluated with five flavonoids including myricetin, quercetin, luteolin, kaempferol and isorhamnetin. Main parameters, which affect extraction efficiencies, are carefully investigated and optimized. Comparative experiments between Sil-CBM-C30 and commercial C18 sorbents indicate that the extraction efficiencies of the former one surpass the latter one. The modification of carbamate-embedded triacontyl group on surface of silica causes analytes extracted by hydrophobic, hydrogen bonding and π-π interactions. Under optimal conditions, good linearities and satisfied LODs and LOQs are achieved. The SPE-HPLC-DAD method is successfully developed and applied for the honey sample analysis.

  4. Novel chiral stationary phases based on peptoid combining a quinine/quinidine moiety through a C9-position carbamate group. (United States)

    Wu, Haibo; Wang, Dongqiang; Song, Guangjun; Ke, Yanxiong; Liang, Xinmiao


    By connecting a quinine or quinidine moiety to the peptoid chain through the C9-position carbamate group, we synthesized two new chiral selectors. After immobilizing them onto 3-mercaptopropyl-modified silica gel, two novel chiral stationary phases were prepared. With neutral, acid, and basic chiral compounds as analytes, we evaluated these two stationary phases and compared their chromatographic performance with chiral columns based on quinine tert-butyl carbamate and the previous peptoid. From the resolution of neutral and basic analytes under normal-phase mode, it was found that the new stationary phases exhibited much better enantioselectivity than the quinine tert-butyl carbamate column; the peptoid moiety played an important role in enantiorecognition, which controlled the elution orders of enantiomers; the assisting role of the cinchona alkaloid moieties was observed in some separations. Under acid polar organic phase mode, it was proved that cinchona alkaloid moieties introduced excellent enantiorecognitions for chiral acid compounds; in some separations, the peptoid moiety affected enantioseparations as well. Overall, chiral moieties with specific enantioselectivity were demonstrated to improve the performance of peptoid chiral stationary phase efficiently.

  5. A mechanism-based 3D-QSAR approach for classification and prediction of acetylcholinesterase inhibitory potency of organophosphate and carbamate analogs (United States)

    Lee, Sehan; Barron, Mace G.


    Organophosphate (OP) and carbamate esters can inhibit acetylcholinesterase (AChE) by binding covalently to a serine residue in the enzyme active site, and their inhibitory potency depends largely on affinity for the enzyme and the reactivity of the ester. Despite this understanding, there has been no mechanism-based in silico approach for classification and prediction of the inhibitory potency of ether OPs or carbamates. This prompted us to develop a three dimensional prediction framework for OPs, carbamates, and their analogs. Inhibitory structures of a compound that can form the covalent bond were identified through analysis of docked conformations of the compound and its metabolites. Inhibitory potencies of the selected structures were then predicted using a previously developed three dimensional quantitative structure-active relationship. This approach was validated with a large number of structurally diverse OP and carbamate compounds encompassing widely used insecticides and structural analogs including OP flame retardants and thio- and dithiocarbamate pesticides. The modeling revealed that: (1) in addition to classical OP metabolic activation, the toxicity of carbamate compounds can be dependent on biotransformation, (2) OP and carbamate analogs such as OP flame retardants and thiocarbamate herbicides can act as AChEI, (3) hydrogen bonds at the oxyanion hole is critical for AChE inhibition through the covalent bond, and (4) π-π interaction with Trp86 is necessary for strong inhibition of AChE. Our combined computation approach provided detailed understanding of the mechanism of action of OP and carbamate compounds and may be useful for screening a diversity of chemical structures for AChE inhibitory potency.

  6. [Degradation of urea and ethyl carbamate in Chinese Rice wine by recombinant acid urease]. (United States)

    Zhou, Jianli; Kang, Zhen; Liu, Qingtao; Du, Guocheng; Chen, Jian


    Ethyl carbamate (EC) as a potential carcinogen commonly exists in traditional fermented foods. It is important eliminate urea that is the precursors of EC in many fermented foods, including Chinese Rice wine. On the basis of achieving high-level overexpression of food-grade ethanol-resistant acid urease, we studied the hydrolysis of urea and EC with the recombinant acid urease. Recombinant acid urease showed degraded urea in both the simulated system with ethanol and Chinese Rice wine (60 mg/L of urea was completely degraded within 25 h), indicating that the recombinant enzyme is suitable for the elimination of urea in Chinese Rice wine. Although recombinant acid urease also has degradation catalytic activity on EC, no obvious degradation of EC was observed. Further investigation results showed that the Km value for urea and EC of the recombinant acid urease was 0.7147 mmol/L and 41.32 mmol/L, respectively. The results provided theoretical foundation for realizing simultaneous degradation of urea and EC.

  7. Surface display of recombinant Drosophila melanogaster acetylcholinesterase for detection of organic phosphorus and carbamate pesticides.

    Directory of Open Access Journals (Sweden)

    Jingquan Li

    Full Text Available Acetylcholinesterase (AChE is commonly used for the detection of organophosphate (OP and carbamate (CB insecticides. However, the cost of this commercially available enzyme is high, making high-throughput insecticide detection improbable. In this study we constructed a new AChE yeast expression system in Saccharomyces cerevisiae for the expression of a highly reactive recombinant AChE originating from Drosophila melanogaster (DmAChE. Specifically, the coding sequence of DmAChE was fused with the 3'-terminal half of an α-agglutinin anchor region, along with an antigen tag for the detection of the recombinant protein. The target sequence was cloned into the yeast expression vector pYes-DEST52, and the signal peptide sequence was replaced with a glucoamylase secretion region for induced expression. The resultant engineered vector was transformed into S. cerevisiae. DmAChE was expressed and displayed on the cell surface after galactose induction. Our results showed that the recombinant protein displayed activity comparable to the commercial enzyme. We also detected different types of OP and CB insecticides through enzyme inhibition assays, with the expressed DmAChE showing high sensitivity. These results show the construction of a new yeast expression system for DmAChE, which can subsequently be used for detecting OP and CB insecticides with reduced economic costs.

  8. Organophosphorus and carbamates residues in milk and feedstuff supplied to dairy cattle

    Directory of Open Access Journals (Sweden)

    Rafael Fagnani


    Full Text Available Considering acute and chronic toxicity effects on human and animal health caused by pesticide residues in food, this study aimed to analyze organophosphorate (OP and carbamate (CB in feedstuff and water destined for dairy cattle, as well as in the milk produced by these animals, through gas chromatography (GC. In the Agreste region of Pernambuco, Brazil, 30 raw milk samples and all components of the animals' diet were collected from several farms. Out of the 30 milk of milk analyzed, six (20% were contaminated with OP, five (16.7% with CB, and one sample with both pesticides. From 48 analyzed feed samples, 15 (31.25% were contaminated with residues of OP, six (12.50% with CB, and one sample was contaminated with both pesticides. Out of 16 water samples analyzed, six (37.50% were contaminated with OP residues, but non with CB. In four dairy farms the pesticides detected in milk were compatible with the active principles found in water and/or foodstuff, suggesting them to be the source of contamination.

  9. Unidirectional cross-tolerance between the carbamate insecticide propoxur and the organophosphate disulfoton in mice. (United States)

    Costa, L G; Murphy, S D


    Previous studies have shown that subchronic treatment of mice with the organophosphate insecticide, disulfoton, or the carbamate insecticide, propoxur, leads to the development of tolerance to their toxicity. Tolerance to disulfoton was due to a decrease in the number of muscarinic cholinergic receptors, while tolerance to propoxur appeared to be due to an induction of hepatic microsomal enzymes. In the present study we investigated if cross-tolerance between disulfoton and propoxur would occur. Cross-tolerance was evaluated by measuring acute toxicities, cholinesterase and carboxylesterase inhibition and hypothermic and antinociceptive effects. Mice tolerant to propoxur were cross-tolerant to the hypothermic and anticholinesterase effects of disulfoton. Similarly, when mice were pretreated with the microsomal enzyme inducer, phenobarbital, the toxicity of disulfoton was decreased. Mice made tolerant to disulfoton were cross-tolerant to the organophosphate chlorpyrifos, but were more sensitive than controls to the toxicity of propoxur. The acute toxicity of the organophosphate malathion was also increased in disulfoton-tolerant mice. Propoxur is metabolized by mixed function oxidases and possibly by a carboxylesterase. While hepatic microsomal enzymes appeared to be unchanged in disulfoton-tolerant mice, brain and liver carboxylesterase activities were significantly inhibited. Pretreatment of mice with the specific carboxylesterase inhibitor triorthotolylphosphate is known to greatly potentiate the toxicity of malathion and also potentiated, to a lesser extent, the toxicity of propoxur.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Solid phase extraction and determination of carbamate pesticides in water samples by reverse-phase HPLC

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Tovar, J.; Santos-Delgado, M.J. [Departamento de Quimica Analitica, Facultad de ciencias Quimicas, Universidad Complutense de Madrid (Spain)


    Solid phase extraction. SPE. using C{sub 1}8 bonded silica cartridges for trace amounts determination of carbaryl, propoxur, thiram, propham and methiocarb in water samples was studied and the breakthrough volume of the cartridges was established. The high enrichment factor and large injection volume admissible in the isocratic reverse-phase HPLC system allows pesticides determination with UV detection at 22o nm even at a concentration lower than 0.05 mug/L. Purified tap natural and underground water samples were spiked with carbamate pesticides in the concentration range 0.16-16.0 mug/L. Large volumes of samples (up to 2L) were passed through available C{sub 1}8, cartridges and eluted with acetonitrile. The preconcentrated samples were analyzed by HPLC using a Spherisorb ODS column with a 42.58 acetonitrile-water mobile phase. From replicate samples, recovery for the pesticides ranged from 79.0 to 103.7% except for thiran which is not retained. Tehe relative standard deviation (n=4 at 0.16 to 1.61 mug/L concetration level) range from 1.1 to 6.8%. (Author) 14 refs.

  11. Determination of Ethyl Carbamate in Alcoholic Beverages and Fermented Foods Sold in Korea (United States)

    Ryu, Dayeon; Choi, Bogyoung; Kim, Eunjoo; Park, Seri; Paeng, Hwijin; Kim, Cho-il; Lee, Jee-yeon; Yoon, Hae Jung


    Ethyl carbamate (EC) classified as a probable human carcinogen (Group 2A) is naturally formed in alcoholic beverages and fermented foods during fermentation process and/or during storage. The objective of this study was to analyze EC in 34 food items including 14 alcoholic beverages and 20 fermented foods sold in Korea. Each food was collected from 18 supermarkets in 9 metropolitan cities in Korea, and then made into composite. According to food composition and alcohol content, samples were divided into four matrices such as apple juice, milk, Soju (liquor containing about 20% alcohol), and rice porridge. The maximum EC value of 151.06 µg/kg was found in Maesilju (liquor made from Maesil and Soju). Whisky and Bokbunjaju (Korean black raspberry wine) contained 9.90 µg/kg and 6.30 µg/kg, respectively. EC was not detected in other alcoholic beverages. Of 20 fermented foods, Japanese-style soy sauce had highest level of 15.59 µg/kg and traditional one contained 4.18 µg/kg. Soybean paste had 1.18 µg/kg, however, EC was not found in other fermented foods. PMID:26483888

  12. Reduced production of ethyl carbamate for wine fermentation by deleting CAR1 in Saccharomyces cerevisiae. (United States)

    Guo, Xue-Wu; Li, Yuan-Zi; Guo, Jian; Wang, Qing; Huang, Shi-Yong; Chen, Ye-Fu; Du, Li-Ping; Xiao, Dong-Guang


    Ethyl carbamate (EC), a pluripotent carcinogen, is mainly formed by a spontaneous chemical reaction of ethanol with urea in wine. The arginine, one of the major amino acids in grape musts, is metabolized by arginase (encoded by CAR1) to ornithine and urea. To reduce the production of urea and EC, an arginase-deficient recombinant strain YZ22 (Δcarl/Δcarl) was constructed from a diploid wine yeast, WY1, by successive deletion of two CAR1 alleles to block the pathway of urea production. The RT-qPCR results indicated that the YZ22 almost did not express CAR1 gene and the specific arginase activity of strain YZ22 was 12.64 times lower than that of parent strain WY1. The fermentation results showed that the content of urea and EC in wine decreased by 77.89 and 73.78 %, respectively. Furthermore, EC was forming in a much lower speed with the lower urea during wine storage. Moreover, the two CAR1 allele deletion strain YZ22 was substantially equivalent to parental strain in terms of growth and fermentation characteristics. Our research also suggested that EC in wine originates mainly from urea that is produced by the arginine.

  13. Molecular recognition by cholesterol esterase of active site ligands: structure-reactivity effects for inhibition by aryl carbamates and subsequent carbamylenzyme turnover. (United States)

    Feaster, S R; Lee, K; Baker, N; Hui, D Y; Quinn, D M


    Interactions of mammalian pancreatic cholesterol esterases from pig and rat with a family of aryl carbamates CnH2n+1NHCOOAr [n = 4-9; Ar = phenyl, p-X-phenyl (X = acetamido, bromo, fluoro, nitro, trifluoromethyl), 2-naphthyl, 2-tetrahydronaphthyl, estronyl] have been investigated, with an aim of delineating the ligand structural features which lead to effective molecular recognition by the active site of the enzyme. These carbamates inhibit the catalytic activity of CEase by rapid carbamylation of the active site, a process that shows saturation kinetics. Subsequent slow decarbamylation usually leads to full restoration of activity, and therefore aryl carbamates are transient inhibitors, or pseudo-substrates, of CEase. Structural variation of carbamate inhibitors allowed molecular recognition in the fatty acid binding and steroid binding loci of the extended active site to be probed, and the electronic nature of the carbamylation transition state to be characterized. Optimal inhibitory activity is observed when the length of the carbamyl function is n = 6 and n = 7 for porcine and rat cholesterol esterases, respectively, equivalent to eight- and nine-carbon fatty acyl chains. In contrast, inhibitory activity increases progressively as the partial molecular volume of the aromatic fragment increases. Hammett plots for p-substituted phenyl-N-hexyl carbamates indicate that the rate-determining step for carbamate inhibition is phenolate anion expulsion. Effects of the bile salt activator taurocholate on the kinetically resolved phases of the pseudo-substrate turnover of aryl carbamates were also studied. Taurocholate increases the affinity of the carbamate for the active site of cholesterol esterase in the reversible, noncovalent complex that precedes carbamylation and increases the rate constants of the serial carbamylation and decarbamylation steps. Structural variation of the N-alkyl chain and of the aryl fused-ring system provides an accounting of bile salt

  14. Urinary concentrations of organophosphate and carbamate pesticides in residents of a vegetarian community. (United States)

    Berman, T; Göen, T; Novack, L; Beacher, L; Grinshpan, L; Segev, D; Tordjman, K


    Few population studies have measured urinary levels of pesticides in individuals with vegan, vegetarian, or organic diets. The objectives of this study were to evaluate whether a vegan/vegetarian diet was associated with increased exposure to organophosphate and carbamate pesticides, and to evaluate the impact of organic consumption on pesticide exposure in vegans and vegetarians. In the current pilot study conducted in 2013-2014, we collected spot urine samples and detailed 24h recall dietary data in 42 adult residents of Amirim, a vegetarian community in Northern Israel. We measured urinary levels of non-specific organophosphate pesticide metabolites (dialkylphosphates, (DAPs)) and specific metabolites of the current-use pesticides chlorpyrifos (3,5,6-trichloro-2-pyridinol (TCPy)), propoxur (-isopropoxyphenol (IPPX)), and carbaryl (1-naphthol). Six DAP metabolites were detected in between 67 and 100% of urine samples, with highest geometric mean concentrations for dimethylphosphate (19.2μg/g). Creatinine-adjusted median concentrations of total DAPs and of TCPy were significantly higher in Amirim residents compared to the general Jewish population in Israel (0.29μmol/g compared to 0.16, p25% of the produce they consume is organic (0.065μmol/L compared to 0.22, pvegetarian community, a positive association between vegetable intake and urinary levels of a chlorpyrifos specific metabolite, and lower levels of total dimethyl phosphate in individuals reporting higher intake of organic produce. Results suggest that consumption of organic produce may offer some protection from increased exposure to organophosphate pesticide residues in vegetarians.

  15. Effects of organophosphate,carbamate and pyrethroid insecticides and their mixtures on neuromuscular junction transmission

    Institute of Scientific and Technical Information of China (English)

    HeFS; XiaoC


    To investigate the effects of organophosphorus (OP),carbamate (Carb),pyrehroid (Pyr) insecticides and their mixtures on neuromuscular junction transmission (NMJT),dimethoate(D) and phoxim(P),methomyl(M),and fenvalerate(F) were selected.Rats were intraperitoneally intoxicated by D,P,M,F,D+M,D+F,P+M,or P+F with the dosage of each LD50 respectively.The function of the NMJT was assessed with the mean consecutive differences (MCD) of the latencies of single fiber action potentials detected by stimulation single fiber electromyography(SSFEMG) at the stimulus frequency of 20 Hz.The SSFEMG was also applied to detect the function of NMJT in 40 patients with OPs and their mixtures poisoning in this study.The results showed that (1)the myasthenia occurred only in rats with OPs and their mixtures poisoning,but not in F,M intoxicated rats.The increase of MCD shown by SSFEMG and induced by OP and their mixtures indicating a post-synaptic block was well correlated with the occurrence of myasthenia both in rats and patients(P<0.001);(2)the increase of MCD in rats of OP poisoning was significant in comparison with the control and F,M intoxicated rats;but was not significantly different from those in rats intoxicated by OP mixtures;(3)the MCDs were significantly increased in IMS patients of both acute OP poisoning and OP mixtures poisoning,but showing no significant difference between the two groups of patients.It is concluded that OP is the only responsible agent for the dysfunction of neuromuscular transmission induced by single OP and OP mixture insecticides which could be sensitively detected by SSFEMG.

  16. Detection of Methomyl, a Carbamate Insecticide, in Food Matrices Using Terahertz Time-Domain Spectroscopy (United States)

    Baek, Seung Hyun; Kang, Ju Hee; Hwang, Yeun Hee; Ok, Kang Min; Kwak, Kyungwon; Chun, Hyang Sook


    The aim of this study was to investigate the feasibility of detecting methomyl, a carbamate insecticide, in food matrices (wheat and rice flours) using terahertz time-domain spectroscopy (THz-TDS). In the frequency range 0.1-3 THz, the characteristic THz absorption peaks of methomyl at room temperature were detected at 1 (33.4 cm-1), 1.64 (54.7 cm-1), and 1.89 (63.0 cm-1) THz. For detailed spectral analysis, the vibrational frequency and intensity of methomyl were calculated using solid-state density functional theory to mimic molecular interactions in the solid state. Qualitatively, the simulated spectrum was in good agreement with the experimental spectrum. Analysis of the individual absorption modes revealed that all of the features in the THz spectrum of methomyl were mainly generated from intermolecular vibrations. The peak appearing at 1 THz (33.4 cm-1) was then selected and tested for its suitability as a fingerprint for detecting methomyl in food matrices. Its absorbance was dose-dependently distinguishable from that of wheat and rice flours. The calibration curve of methomyl had a regression coefficient of >0.974 and a detection limit of <3.74 %. Accuracy and precision expressed as recovery and relative standard deviation in interday repeatability were in the ranges 78.0-96.5 and 2.83-4.98 %, respectively. Our results suggest that THz-TDS can be used for the rapid detection of methomyl in foods, but its sensitivity needs to be improved.

  17. ERK-dependent phosphorylation of HSF1 mediates chemotherapeutic resistance to benzimidazole carbamates in colorectal cancer cells. (United States)

    Wales, Christina T K; Taylor, Frederick R; Higa, Allan T; McAllister, Harvey A; Jacobs, Aaron T


    Drugs containing the benzimidazole carbamate scaffold include anthelmintic and antifungal agents, and they are now also recognized as having potential applications in the treatment of colorectal and other cancers. These agents act by binding to β-tubulin, and in doing so they disrupt microtubules, arrest cell division, and promote apoptotic cell death in malignant cells. We have evaluated several commercially available benzimidazole carbamates for cytotoxic activity in colorectal cancer cells. In addition to cytotoxicity, we also observe activation of the transcription factor, heat shock factor-1 (HSF1). HSF1 is well known to mediate a cytoprotective response that promotes tumor cell survival and drug resistance. Here, we show that biochemical inhibition with the HSF1 inhibitor KRIBB11 or siRNA-based silencing of HSF1 results in a significant enhancement of drug potency, causing an approximately two-fold decrease in IC50 values of parbendazole and nocodazole. We also define a mechanism for drug-induced HSF1 activation, which results from a phosphorylation event at Ser326 that is dependent on the activation of the extracellular regulated protein kinase-1/2 (ERK-1/2) mitogen-activated protein kinase pathway. Inhibition of the upstream kinase MEK-1/2 with U0126 attenuates the phosphorylation of both ERK-1/2 and HSF1, and significantly enhances drug cytotoxicity. From these data we propose a unique model whereby the ERK-1/2-dependent activation of HSF1 promotes chemotherapeutic resistance to benzimidazole carbamates. Therefore, targeting the ERK-1/2 signaling cascade is a potential strategy for HSF1 inhibition and a means of enhancing the cytotoxicity of these agents.

  18. Extraction of carbamate pesticides in fruit samples by graphene reinforced hollow fibre liquid microextraction followed by high performance liquid chromatographic detection. (United States)

    Ma, Xiaoxing; Wang, Juntao; Wu, Qiuhua; Wang, Chun; Wang, Zhi


    Graphene reinforced hollow fibre liquid phase microextraction combined with high performance liquid chromatography-diode array detection was developed for the determination of some carbamate pesticides (metolcarb, carbaryl, isoprocarb, and diethofencarb) in fruit samples. The main parameters that affect the extraction efficiency for the carbamates were investigated. Under the optimum conditions, a good linearity was observed in the range of 1.0-100.0 ng g(-1) for carbaryl and 3.0-100.0 ng g(-1) for the other three analytes, with the correlation coefficients (r) of 0.9965-0.9993. The limits of detection of the method ranged from 0.2 to 1.0 ng g(-1). The relative standard deviations were in the range from 6.2% to 7.8%. The results indicated that the developed method is sensitive and efficient for the determination of the carbamate pesticides in fruit samples.

  19. tert-Butyl N-[6-(N,N-dipropylcarbamoyl-1,3-benzothiazol-2-yl]carbamate

    Directory of Open Access Journals (Sweden)

    Xin Fang


    Full Text Available The title compound C19H27N3O3S, crystallizes with two unique molecules in the asymmetric unit. The benzene ring of each benzothiazole unit carries a dipropylcarbamoyl substituent in the 6-position and a tert-butyl carbamate unit on each thiazole ring. In the crystal structure, intermolecular N—H...N and weak C—H...O hydrogen bonds form centrosymmetric dimers. Additional C—H...O contacts construct a three-dimensional network. A very weak C—H...π contact is also present.

  20. Synthesis and antimicrobial activities of new oxime carbamates of 3-aryl-2-thioquinazolin-4(3H)-one

    Indian Academy of Sciences (India)

    Suresh S Patil; Swati D Jadhav; M B Deshmukh


    S-alkylation of 3-aryl-2-thioquinazolin-4(3H)-one (1) with chloroacetone gave 2-(propanonyl thio)-3-arylquinazol-4(3H)ones (2). Further, the treatment of compound (2) with hydroxylamine hydrochloride gave the corresponding oximes (3) which on reaction with phenyl isocyanate in THF yielded corresponding oxime carbamates 4. The synthesized compounds have been confirmed using IR and 1H NMR, mass spectral data together with elemental analysis. All newly synthesized compounds have been tested for their antibacterial and antifungal activities.

  1. High lethality and minimal variation after acute self-poisoning with carbamate insecticides in Sri Lanka – implications for global suicide prevention (United States)

    Lamb, Thomas; Selvarajah, Liza R.; Mohamed, Fahim; Jayamanne, Shaluka; Gawarammana, Indika; Mostafa, Ahmed; Buckley, Nicholas A.; Roberts, Michael S.; Eddleston, Michael


    Abstract Background: Highly hazardous organophosphorus (OP) insecticides are responsible for most pesticide poisoning deaths. As they are removed from agricultural practice, they are often replaced by carbamate insecticides of perceived lower toxicity. However, relatively little is known about poisoning with these insecticides. Methods: We prospectively studied 1288 patients self-poisoned with carbamate insecticides admitted to six Sri Lankan hospitals. Clinical outcomes were recorded for each patient and plasma carbamate concentration measured in a sample to confirm the carbamate ingested. Findings: Patients had ingested 3% carbofuran powder (719), carbosulfan EC25 liquid (25% w/v, 389), or fenobucarb EC50 liquid (50% w/v, 127) formulations, carbamate insecticides of WHO Toxicity Classes Ib, II, and II, respectively. Intubation and ventilation was required for 183 (14.2%) patients while 71 (5.5%) died. Compared with carbofuran, poisoning with carbosulfan or fenobucarb was associated with significantly higher risk of death [carbofuran 2.2%; carbosulfan 11.1%, OR 5.5 (95% CI 3.0–9.8); fenobucarb 6.3%, OR 3.0 (1.2–7.1)] and intubation [carbofuran 6.1%; carbosulfan 27.0%, OR 5.7 (3.9–8.3); fenobucarb 18.9%, OR 3.6 (2.1–6.1)]. The clinical presentation and cause of death did not differ markedly between carbamates. Median time to death was similar: carbofuran 42.3 h (IQR 5.5–67.3), carbosulfan 21.3 h (11.5–71.3), and fenobucarb 25.3 h (17.3–72.1) (p = 0.99); no patients showed delayed onset of toxicity akin to the intermediate syndrome seen after OP insecticide poisoning. For survivors, median duration of intubation was 67.8 h (IQR 27.5–118.8) with no difference in duration between carbamates. Reduced GCS at presentation was associated with worse outcome although some patients with carbosulfan died after presentation with normal GCS. Conclusions: We did not find carbamate insecticide self-poisoning to vary markedly according to the carbamate

  2. Determination of Carbamate and Organophosphorus Pesticides in Vegetable Samples and the Efficiency of Gamma-Radiation in Their Removal

    Directory of Open Access Journals (Sweden)

    Muhammed Alamgir Zaman Chowdhury


    Full Text Available In the present study, the residual pesticide levels were determined in eggplants (Solanum melongena (n=16, purchased from four different markets in Dhaka, Bangladesh. The carbamate and organophosphorus pesticide residual levels were determined by high performance liquid chromatography (HPLC, and the efficiency of gamma radiation on pesticide removal in three different types of vegetables was also studied. Many (50% of the samples contained pesticides, and three samples had residual levels above the maximum residue levels determined by the World Health Organisation. Three carbamates (carbaryl, carbofuran, and pirimicarb and six organophosphates (phenthoate, diazinon, parathion, dimethoate, phosphamidon, and pirimiphos-methyl were detected in eggplant samples; the highest carbofuran level detected was 1.86 mg/kg, while phenthoate was detected at 0.311 mg/kg. Gamma radiation decreased pesticide levels proportionately with increasing radiation doses. Diazinon, chlorpyrifos, and phosphamidon were reduced by 40–48%, 35–43%, and 30–45%, respectively, when a radiation strength of 0.5 kGy was utilized. However, when the radiation dose was increased to 1.0 kGy, the levels of the pesticides were reduced to 85–90%, 80–91%, and 90–95%, respectively. In summary, our study revealed that pesticide residues are present at high amounts in vegetable samples and that gamma radiation at 1.0 kGy can remove 80–95% of some pesticides.

  3. Equilibrium Dynamics of β-N-Methylamino-L-Alanine (BMAA) and Its Carbamate Adducts at Physiological Conditions (United States)

    Zimmerman, David; Goto, Joy J.; Krishnan, Viswanathan V


    Elevated incidences of Amyotrophic Lateral Sclerosis/Parkinsonism Dementia complex (ALS/PDC) is associated with β-methylamino-L-alanine (BMAA), a non-protein amino acid. In particular, the native Chamorro people living in the island of Guam were exposed to BMAA by consuming a diet based on the cycad seeds. Carbamylated forms of BMAA are glutamate analogues. The mechanism of neurotoxicity of the BMAA is not completely understood, and BMAA acting as a glutamate receptor agonist may lead to excitotoxicity that interferes with glutamate transport systems. Though the interaction of BMAA with bicarbonate is known to produce carbamate adducts, here we demonstrate that BMAA and its primary and secondary adducts coexist in solution and undergoes a chemical exchange among them. Furthermore, we determined the rates of formation/cleavage of the carbamate adducts under equilibrium conditions using two-dimensional proton exchange NMR spectroscopy (EXSY). The coexistence of the multiple forms of BMAA at physiological conditions adds to the complexity of the mechanisms by which BMAA functions as a neurotoxin. PMID:27513925

  4. Optimization and validation of liquid-liquid extraction with low temperature partitioning for determination of carbamates in water

    Energy Technology Data Exchange (ETDEWEB)

    Machado Goulart, Simone; Domingos Alves, Renata; Neves, Antonio Augusto; Queiroz, Jose Humberto de; Conde de Assis, Tamires [Departamento de Quimica, Universidade Federal de Vicosa, Vila Gianetti, Casa 24, 36 570-000 Vicosa, MG (Brazil); Queiroz, Maria Eliana L.R. de, E-mail: [Departamento de Quimica, Universidade Federal de Vicosa, Vila Gianetti, Casa 24, 36 570-000 Vicosa, MG (Brazil)


    Using a 2{sup 3} experimental design, liquid-liquid extraction with low temperature partitioning (LLE-LTP) was optimized and validated for analysis of three carbamates (aldicarb, carbofuran and carbaryl) in water samples. In this method, 2.0 mL of sample is placed in contact with 4.0 mL of acetonitrile. After agitation, the sample is placed in a freezer for 3 h for phase separation. The organic extract is analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). For validation of the technique, the following figures of merit were evaluated: accuracy, precision, detection and quantification limits, linearity, sensibility and selectivity. Extraction recovery percentages of the carbamates aldicarb, carbofuran and carbaryl were 90%, 95% and 96%, respectively. Even though extremely low volumes of sample and solvent were used, the extraction method was selective and the detection and quantification limits were between 5.0 and 10.0 {mu}g L{sup -1}, and 17.0 and 33.0 {mu}g L{sup -1}, respectively.

  5. Investigations on Blood Activities of Some Enzymes in Dogs After Acute Intoxication with the Carbamate Insecticide Carbofuran

    Directory of Open Access Journals (Sweden)

    Rumen Binev


    Full Text Available Experiments for monitoring of changes in blood enzyme activities were carried out in dogs after acute intoxication with the carbamate insecticide carbofuran (Carbosan 35 СТ. The studies involved one control and 6 experimental groups of dogs (total n=42, treated once orally with increasing doses of the preparation via oesophageal probe: 0.525 mg/kg (experimental group I, 1.05 mg/kg (experimental group II, 2.1 mg/kg (experimental group III, 3.5 mg/kg (experimental group IV, 5.25 mg/kg (experimental group V and 10.5 mg/kg (LD50, (experimental group VI, corresponding to 1/20, 1/10, 1/5, 1/3, 1/2 and LD50, oral doses for albino rats. Blood samples were obtained from v. antebrachi cephalica or v. jugularis in the course of 3 consecutive days prior to the treatment (hours -48, -24 and 0 and on post treatment hours 1, 3, 5, 7, 24 and 48 from all groups for analysis of acetylcholinesterase (AChE, aspartate aminotransferase (ASAT, alanine aminotransferase (ALAT, amylase (AMY, gamma-glutamyltransferase (g-GT, alkaline phosphatase (ALP and lactate dehydrogenase (LDH. It was established that the tested carbamate insecticide provoked lower blood activity of AChE and increased the levels of ASAT, ALAT, AMY, g-GT, AP and LDH between post treatment hours 1 and 7; afterwards, the studied parameters regained the respective control values.

  6. Preparation of a graphene-based magnetic nanocomposite for the extraction of carbamate pesticides from environmental water samples. (United States)

    Wu, Qiuhua; Zhao, Guangying; Feng, Cheng; Wang, Chun; Wang, Zhi


    A graphene-based magnetic nanocomposite was synthesized and used for the first time as an effective adsorbent for the preconcentration of the five carbamate pesticides (metolcarb, carbofuran, pirimicarb, isoprocarb and diethofencarb) in environmental water samples prior to high performance liquid chromatography-diode array detection. The properties of the magnetic nanocomposite were characterized by scanning electron microscopy and X-ray diffraction. This novel graphene-based magnetic nanocomposite showed great adsorptive ability towards the analytes. The method, which takes the advantages of both nanoparticle adsorption and magnetic phase separation from the sample solution, could avoid some of the time-consuming experimental procedures related to the traditional solid phase extraction. Various experimental parameters that could affect the extraction efficiencies have been investigated. Under the optimum conditions, the enrichment factors of the method for the analytes were in the range from 474 to 868. A linear response was achieved in the concentration range of 0.1-50 ng mL(-1). The limits of detection of the method at a signal to noise ratio of 3 for the pesticides were 0.02-0.04 ng mL(-1). Compared with the dispersive liquid-liquid microextraction and the ultrasound-assisted surfactant-enhanced emulsification microextraction, much higher enrichment factors and sensitivities were achieved with the developed method. The method has been successfully applied for the determination of the carbamate pesticides in environmental water samples.


    A physiologically-based pharmacokinetic (PBPK) model for a mixture of N-methyl carbamate pesticides was developed based on single chemical models. The model was used to compare urinary metabolite concentrations to levels from National Health and Nutrition Examination Survey (NHA...

  8. Formation of a unique zinc carbamate by CO2 fixation: implications for the reactivity of tetra-azamacrocycle ligated Zn(II) complexes. (United States)

    Notni, Johannes; Schenk, Stephan; Görls, Helmar; Breitzke, Hergen; Anders, Ernst


    The macrocyclic ligand [13]aneN 4 ( L1, 1,4,7,10-tetra-azacyclotridecane) was reacted with Zn(II) perchlorate and CO 2 in an alkaline methanol solution. It was found that, by means of subtle changes in reaction conditions, two types of complexes can be obtained: (a) the mu 3 carbonate complex 1, {[Zn( L1)] 3(mu 3-CO 3)}(ClO 4) 4, rhombohedral crystals, space group R3 c, with pentacoordinate zinc in a trigonal bipyramidal enviroment, and (b) an unprecedenced dimeric Zn(II) carbamate structure, 2, [Zn( L2)] 2(ClO 4) 2, monoclinic crystals, space group P2 1/ n. The ligand L2 (4-carboxyl-1,4,7,10-tetra-azacyclotridecane) is a carbamate derivative of L1, obtained by transformation of a hydrogen atom of one of the NH moieties into carbamate by means of CO 2 uptake. In compound 2, the distorted tetrahedral Zn(II) coordinates to the carbamate moiety in a monodentate manner. Most notably, carbamate formation can occur upon reaction of CO 2 with the [Zn L1] (2+) complex, which implicates that a Zn-N linkage is cleaved upon attack of CO 2. Since complexes of tetra-azamacrocycles and Zn(II) are routinely applied for enzyme model studies, this finding implies that the Zn-azamacrocycle moiety generally should no longer be considered to play always only an innocent role in reactions. Rather, its reactivity has to be taken into account in respective investigations. In the presence of water, 2 is transformed readily into carbonate 1. Both compounds have been additionally characterized by solid-state NMR and infrared spectroscopy. A thorough comparison of 1 with related azamacrocycle ligated zinc(II) carbonates as well as a discussion of plausible reaction paths for the formation of 2 are given. Furthermore, the infrared absorptions of the carbamate moiety have been assigned by calculating the vibrational modes of the carbamate complex using DFT methods and the vibrational spectroscopy calculation program package SNF.

  9. Evidence of carbamate resistance in urban populations of Anopheles gambiae s.s. mosquitoes resistant to DDT and deltamethrin insecticides in Lagos, South-Western Nigeria

    Directory of Open Access Journals (Sweden)

    Oduola Adedayo O


    Full Text Available Abstract Background Resistance monitoring is essential in ensuring the success of insecticide based vector control programmes. This study was carried out to assess the susceptibility status of urban populations of Anopheles gambiae to carbamate insecticide being considered for vector control in mosquito populations previously reported to be resistant to DDT and permethrin. Methods Two – three day old adult female Anopheles mosquitoes reared from larval collections in 11 study sites from Local Government Areas of Lagos were exposed to test papers impregnated with DDT 4%, deltamethrin 0.05% and propoxur 0.1% insecticides. Additional tests were carried out to determine the susceptibility status of the Anopheles gambiae population to bendiocarb insecticide. Members of the A. gambiae complex, the molecular forms, were identified by PCR assays. The involvement of metabolic enzymes in carbamate resistance was assessed using Piperonyl butoxide (PBO synergist assays. The presence of kdr-w/e and ace-1R point mutations responsible for DDT-pyrethroid and carbamate resistance mechanisms was also investigated by PCR. Results Propoxur resistance was found in 10 out of the 11 study sites. Resistance to three classes of insecticides was observed in five urban localities. Mortality rates in mosquitoes exposed to deltamethrin and propoxur did not show any significant difference (P > 0.05 but was significantly higher (P A. gambiae s.s (M form. The kdr -w point mutation at allelic frequencies between 45%-77% was identified as one of the resistant mechanisms responsible for DDT and pyrethroid resistance. Ace-1R point mutation was absent in the carbamate resistant population. However, the possible involvement of metabolic resistance was confirmed by synergistic assays conducted. Conclusion Evidence of carbamate resistance in A. gambiae populations already harbouring resistance to DDT and permethrin is a clear indication that calls for the implementation of

  10. Synthesis and reactivity of cyclic-carbamate derivatives%环状氨基甲酸酯衍生物的合成及反应研究

    Institute of Scientific and Technical Information of China (English)

    王静; 郭爽; 王家喜


    Cyclic carbamate has been prepared by the reaction of ethanolamine with dimethyl carbonate as raw material and zinc acetate as catalyst. The cyclic carbamate reacted with methyl acrylate producing methyl 3- (2-oxo-oxazolidin-3-yl) propanoate, which reacted with n-butylamine and 1,6-hexanediamine to give mono and bis cyclic carbamate derivatives. The attack of amine to carbonyl of heterocyclic ring of carbamate produced the hydroxylethyl substituted urea, while the attack to carbon-oxygen bond generated carbamic acid, which further underwent dehydration forming cyclic urea and/or de-carbon dioxide forming polyamine. The products were characterized by NMR and FT-IR. The reaction mechanism is finally proposed.%以乙醇胺和碳酸二甲酯为原料,在醋酸锌的催化下合成环状氨基甲酸酯,与丙烯酸甲酯反应制备3-(2-噁唑烷酮)丙酸甲酯,在K2CO3催化下进一步与正丁胺、1,6-己二胺发生酰胺化反应,得到了单、双环状氨基甲酸酯衍生物.有机胺与环状氨基甲酸酯的羰基反应形成羟乙基取代脲,与烷氧基反应形成开环的胺基甲酸,该化合物进一步脱水形成环状脲,脱二氧化碳形成多胺化合物.用NMR和红外谱图对开环产物进行表征,并初步探讨了其反应历程.

  11. 氨基甲酸酯淀粉浆料的制备及上浆性能%Manufacture and Sizing Performance of Carbamate Starch Size Mixture

    Institute of Scientific and Technical Information of China (English)

    刘志军; 许冬生


    探讨氨基甲酸酯淀粉的取代度对氨基甲酸酯淀粉浆料上浆性能的影响.通过改变氧化铵对淀粉的投料比,制备了一系列具有不同变性程度的氨基甲酸酯淀粉,对不同取代度的氨基甲酸酯淀粉浆料的浆液性能及对棉纤维的黏附性能进行了测试.结果表明:当取代度不超过0.053时,随氨基甲酸酯淀粉取代度的提高,浆液黏度降低,热稳定性提高,对棉纤维的黏着力增大.指出:氨基甲酸酯变性有利于改善淀粉对纯棉经纱的上浆性能.%Effect of carbamate starch substitution degree on size mixture property was discussed. Through changing feed ratio of ammonium chloride to starch,a series of carbamate starch with different substitution degree were made. Sizing property of carbamate starch with different substitution degree and adhesion performance to cotton fiber were tested. The result shows when the substitution degree is less 0. 053 and substitution degree of carbamate starch is increasing,sizing viscosity is reduced, the thermal stability is increased, the adhesion to cotton fiber is increased. It is pointed out that sizing property of carbamate starch to pure cotton yarn can be improved.

  12. Anthelmintic profile of methyl 5(6)-(4-methylpiperidin-1-yl) carbonylbenzimidazole-2-carbamate in experimental helminthiases. (United States)

    Gupta, S; Khan, A M; Jain, M K; Katiyar, J C; Naim, S S; Singh, S K; Sharma, S


    Biological evaluation of methyl 5(6)-(4-methylpiperidin-1-yl) carbonylbenzimidazole-2-carbamate against Ancylostoma ceylanicum, Nippostrongylus brasiliensis, Syphacia obvelata, Hymenolepis nana, H. diminuta and Cysticercus fasciolaris in experimental animals is reported. The compound (mg/kg) causes 100% elimination of A. ceylanicum (25 x 1), N. brasiliensis (100 x 1), S. obvelata (50 x 1), H. nana (250 x 3) and C. fasciolaris (50 x 10). It was also effective against the developing larvae (L3, L4 and L5) of A. ceylanicum at a single oral dose of 100 mg/kg. Another study indicated that the compound elicits 100% response within 32 hr of drug administration. The drug is well tolerated and LD50 is greater than 4500 mg/kg.

  13. Biodegradation of carbamate pesticides by natural river biofilms in different seasons and their effects on biofilm community structure. (United States)

    Tien, Chien-Jung; Lin, Mon-Chu; Chiu, Wan-Hsin; Chen, Colin S


    This study investigated the ability of natural river biofilms from different seasons to degrade the carbamate pesticides methomyl, carbaryl and carbofuran in single and multiple pesticide systems, and the effects of these pesticides on algal and bacterial communities within biofilms. Spring biofilms had the lowest biomass of algae and bacteria but showed the highest methomyl degradation (>99%) and dissipation rates, suggesting that they might contain microorganisms with high methomyl degradation abilities. Degradation of carbofuran (54.1-59.5%) by biofilms in four seasons was similar, but low degradation of carbaryl (0-27.5%) was observed. The coexistence of other pesticides was found to cause certain effects on pesticide degradation and primarily resulted in lower diversity of diatoms and bacteria than when using a single pesticide. The tolerant diatoms and bacteria potentially having the ability to degrade test pesticides were identified. River biofilms could be suitable biomaterials or used to isolate degraders for bioremediating pesticide-contaminated water.

  14. The arginine deiminase pathway of koji bacteria is involved in ethyl carbamate precursor production in soy sauce. (United States)

    Zhang, Jiran; Fang, Fang; Chen, Jian; Du, Guocheng


    Ethyl carbamate (EC) is a group 2A carcinogen generated from a few precursors in many fermented foods and alcoholic beverages. Citrulline, urea, carbamoyl phosphate, and ethanol are common precursors detected in fermented foods. In this study, citrulline was proved to be the main EC precursor in soy sauce, which was found to be accumulated in moromi mash period and correlated with the utilization of arginine by koji bacteria. Six koji isolates belonging to three genera were identified to be able to accumulate citrulline via the arginine deiminase (ADI) pathway. Among these strains, only Pediococcus acidilactici retained high activities in synthesis and accumulation of citrulline in the presence of high concentration of sodium chloride. These results suggested that P. acidilactici is responsible for the accumulation of citrulline, one of the EC precursors, in the process of soy sauce fermentation.

  15. Chelation-Assisted Substrate-Controlled Asymmetric Lithiation-Allylboration of Chiral Carbamate 1,2,4-Butanetriol Acetonide

    Directory of Open Access Journals (Sweden)

    Adeem Mahmood


    Full Text Available The lithiation of 2-(2,2-dimethyl-1,3-dioxolan-4-ylethyl diisopropylcarbamate (1 is achieved freely by sec-butyllithium in diethylether with high lk-diastereoselectivity: the bicyclic chelate complexes 3a and 3b are reacted with electrophiles to form optically active precursors 4a and 4b with >95% diastereoselectivity. In addition, tertiary diamines can undergo an external complexation in contest with the internal oxygen ligand, leading to improved stereoselectivities. The further reactions of lithiated carbamates with trans alkenyl-9-BBN derivatives after 1,2 metallate rearrangements, gave the key intermediate α-substituted allylic boranes 7. Subsequent allylboration of aldehydes gave (Z-anti-homoallylic alcohols 8 in good yield and excellent d.r.

  16. Enantioseparation of Neutral Compounds on a Quinine Carbamate-Immobilized Zirconia in Reversed-Phase Capillary Electrochromatography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Mun Rak; Gwon, Ju Rim; Park, Jung Hag [Yeungnam University, Gyeongsan (Korea, Republic of)


    Quinine (QN) is a weak anion-exchange type chiral selector and QN-based silica stationary phases have been widely used for enantioseparation of acidic chiral analytes in HPLC and recently in CEC. In this work we report enantioseparation of non-acidic chiral analytes on a quinine carbamate-immobilized zirconia (QNZ) in reversed-phase (RP) CEC. Influences of pH, composition of the buffer, acetonitrile content and the applied voltage on enantioseparation were examined. Enantiomers of the analytes investigated are well separated in acetonitrile/phosphate buffer mobile phases. Separation data on QNZ were compared to those on QN-bonded silica (QNS). Retention was longer but better enantioselectivity and resolution were obtained on QNZ than QNS.

  17. Measurement of pyrethroid, organophosphorus, and carbamate insecticides in human plasma using isotope dilution gas chromatography-high resolution mass spectrometry. (United States)

    Pérez, José J; Williams, Megan K; Weerasekera, Gayanga; Smith, Kimberly; Whyatt, Robin M; Needham, Larry L; Barr, Dana Boyd


    We have developed a gas chromatography-high resolution mass spectrometry method for measuring pyrethroid, organophosphorus, carbamate and fipronil pesticides and the synergist piperonyl butoxide in human plasma. Plasma samples were extracted using solid phase extraction and were then concentrated for injection and analysis using isotope dilution gas chromatography-high resolution mass spectrometry. The limits of detection ranged from 10 to 158 pg/mL with relative recoveries at concentrations near the LODs (e.g., 25 or 250 pg/mL) ranging from 87% to 156% (9 of the 16 compounds were within ±15% of 100%). The extraction recoveries ranged from 20% to 98% and the overall method relative standard deviations were typically less than 20% with some exceptions. Analytical characteristics were determined at 25, 250, and 1000 pg/mL.

  18. Ethyl Carbamate in Alcoholic Beverages from Mexico (Tequila, Mezcal, Bacanora, Sotol and Guatemala (Cuxa: Market Survey and Risk Assessment

    Directory of Open Access Journals (Sweden)

    Jürgen Rehm


    Full Text Available Ethyl carbamate (EC is a recognized genotoxic carcinogen, with widespread occurrence in fermented foods and beverages. No data on its occurrence in alcoholic beverages from Mexico or Central America is available. Samples of agave spirits including tequila, mezcal, bacanora and sotol (n=110, and of the sugarcane spirit cuxa (n=16 were purchased in Mexico and Guatemala, respectively, and analyzed for EC. The incidence of EC contamination was higher in Mexico than in Guatemala, however, concentrations were below international guideline levels (<0.15 mg/L. Risk assessment found the Margin of Exposure (MOE in line with that of European spirits. It is therefore unlikely that EC plays a role in high rates of liver cirrhosis reported in Mexico.

  19. Ethyl carbamate in alcoholic beverages from Mexico (tequila, mezcal, bacanora, sotol) and Guatemala (cuxa): market survey and risk assessment. (United States)

    Lachenmeier, Dirk W; Kanteres, Fotis; Kuballa, Thomas; López, Mercedes G; Rehm, Jürgen


    Ethyl carbamate (EC) is a recognized genotoxic carcinogen, with widespread occurrence in fermented foods and beverages. No data on its occurrence in alcoholic beverages from Mexico or Central America is available. Samples of agave spirits including tequila, mezcal, bacanora and sotol (n=110), and of the sugarcane spirit cuxa (n=16) were purchased in Mexico and Guatemala, respectively, and analyzed for EC. The incidence of EC contamination was higher in Mexico than in Guatemala, however, concentrations were below international guideline levels (<0.15 mg/L). Risk assessment found the Margin of Exposure (MOE) in line with that of European spirits. It is therefore unlikely that EC plays a role in high rates of liver cirrhosis reported in Mexico.

  20. Influence of Solvent on Reaction Path to Synthesis of Methyl N-Phenyl Carbamate from Aniline, CO2 and Methanol

    Institute of Scientific and Technical Information of China (English)

    安华良; 张丽丽; 苑保国; 赵新强; 王延吉


    Methyl N-phenyl carbamate (MPC), an important organic chemical, can be synthesized from aniline, CO2 and methanol. Catalyst Cu-Fe/ZrO2-SiO2 was first prepared and its catalytic performance for MPC synthesis was evaluated. Then the influence of solvent on the reaction path of MPC synthesis was investigated. It is found that the reaction intermediate is different with acetonitrile or methanol as a solvent. With acetonitrile as a solvent, the synthesis of MPC follows the reaction path with diphenyl urea as the intermediate, while with methanol as a solvent the reaction occurs via the reaction path with dimethyl carbonate as the intermediate. The catalytic mecha-nism of cooperative catalysis comprising metal sites, Lewis acid sites and Lewis base sites is proposed according to different reaction intermediates.

  1. Synthesis, screening for antiacetylcholinesterase activity and binding mode prediction of a new series of [3-(disubstituted-phosphate)-4,4,4-trifluoro-butyl]-carbamic acid ethyl esters

    Energy Technology Data Exchange (ETDEWEB)

    Zanatta, Nilo; Marchi, Tiago M.; Bonacorso, Helio G.; Martins, Marcos A.P.; Flores, Alex F.C. [Universidade Federal de Santa Maria, RS (Brazil). Dept. de Quimica. Nucleo de Quimica de Heterociclos]. E-mail:; Borchhardt, Deise M.; Andricopulo, Adriano D.; Salum, Livia B. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Centro de Biotecnologia Molecular Estrutural. Lab. de Quimica Medicinal e Computacional; Carpes, Adriana D.; Schetinger, Maria R.C. [Universidade Federal de Santa Maria, RS (Brazil). Dept. de Quimica. Lab. de Enzimologia Toxicologica


    A series of nine new [3-(disubstituted-phosphate)-4,4,4-trifluoro-butyl]-carbamic acid ethyl esters (phosphate-carbamate compounds) was obtained through the reaction of (4,4,4-trifluoro-3-hydroxybut-1-yl)-carbamic acid ethyl esters with phosphorus oxychloride followed by the addition of alcohols. The products were characterized by {sup 1}H, {sup 13}C, {sup 31}P, and {sup 19}F NMR spectroscopy, GC-MS, and elemental analysis. All the synthesized compounds were screened for acetylcholinesterase (AChE) inhibitory activity using the Ellman method. All compounds containing phosphate and carbamate pharmacophores in their structures showed enzyme inhibition, being the compound bearing the diethoxy phosphate group (2b) the most active compound. Molecular modeling studies were performed to investigate the detailed interactions between AChE active site and small-molecule inhibitor candidates, providing valuable structural insights into AChE inhibition. (author)

  2. Different hydrogen-bonded chains in the crystal structures of three alkyl N-[(E-1-(2-benzylidene-1-methylhydrazinyl-3-hydroxy-1-oxopropan-2-yl]carbamates

    Directory of Open Access Journals (Sweden)

    Thais C. M. Noguiera


    Full Text Available The crystal structures of three methylated hydrazine carbamate derivatives prepared by multi-step syntheses from l-serine are presented, namely benzyl N-{(E-1-[2-(4-cyanobenzylidene-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C20H20N4O4, tert-butyl N-{(E-1-[2-(4-cyanobenzylidene-1-methylhydrazinyl]-3-hydroxy-1-oxopropan-2-yl}carbamate, C17H22N4O4, and tert-butyl N-[(E-1-(2-benzylidene-1-methylhydrazinyl-3-hydroxy-1-oxopropan-2-yl]carbamate, C16H23N3O4. One of them shows that an unexpected racemization has occurred during the mild-condition methylation reaction. In each crystal structure, the molecules are linked into chains by O—H...O hydrogen bonds, but with significant differences between them.

  3. Vortex-assisted surfactant-enhanced emulsification liquid-liquid microextraction for the determination of carbamates in juices by micellar electrokinetic chromatography tandem mass spectrometry. (United States)

    Moreno-González, David; Huertas-Pérez, José F; García-Campaña, Ana M; Gámiz-Gracia, Laura


    A new method based on vortex-assisted surfactant-enhanced-emulsification liquid-liquid microextraction has been developed for the extraction of carbamate pesticides in juice samples prior to their determination by micellar electrokinetic chromatography coupled to tandem mass spectrometry. This sample treatment allowed the satisfactory extraction and the extract clean-up of 25 carbamates from different fruit and vegetal juices (banana, tomato, and peach). In this study, the addition of ammonium perfluorooctanoate in the aqueous sample in combination with vortex agitation, provided very clean extracts with short extraction times. Under optimized conditions, recoveries of the proposed method for these pesticides from fortified juice samples ranged from 81% to 104%, with relative standard deviations lower than 15%. Limits of quantification were between 2.3µgkg(-)(1) and 4.7µgkg(-)(1), showing the high sensitivity of this fast and simple method.

  4. A Novel Non-phosgene Process for the Synthesis of Methyl N-Phenyl Carbamate from Methanol and Phenylurea:Effect of Solvent and Catalyst

    Institute of Scientific and Technical Information of China (English)

    WANG,Xin-Kui(王心葵); YAN,Shi-Run(闫世润); CAO,Yong(曹勇); FAN,Kang-Nian(范康年); HE,He-Yong(贺鹤勇); KANG,Mao-Qing(亢茂青); PENG,Shao-Yi(彭少逸)


    A novel environmentally benign process for the synthesis of methyl N-phenyl carbamate (MPC) from methanol and phenylurea was studied. Effect of solvent and catalyst on the reaction behavior was investigated. The IR spectra of methanol and phenylurea dissolved in different solvents were also recorded. Compared with use of methanol as both a reactant and a solvent, phenylurea conversion and selectivity to MPC increased by using toluene, benzene or anisole as a solvent, while phenylurea conversion decreased slightly by using n-octane as a solvent. The phenylurea conversion declined nearly 50% when dimethyl sulfoxide (DMSO) was used as a reaction media, and MPC selectivity decreased as well. The catalytic reaction tests showed that a basic catalyst enhanced the selectivity to MPC while an acidic catalyst promoted the formation of methyl carbamate and aniline. Moderate degree of basicity showed the best catalytic performance in the cases studied.

  5. Regio-, Diastereo-, and Enantioselective Nitroso-Diels-Alder Reaction of 1,3-Diene-1-carbamates Catalyzed by Chiral Phosphoric Acids. (United States)

    Pous, Jonathan; Courant, Thibaut; Bernadat, Guillaume; Iorga, Bogdan I; Blanchard, Florent; Masson, Géraldine


    Chiral phosphoric acid-catalyzed asymmetric nitroso-Diels-Alder reaction of nitrosoarenes with carbamate-dienes afforded cis-3,6-disubstituted dihydro-1,2-oxazines in high yields with excellent regio-, diastereo-, and enantioselectivities. Interestingly, we observed that the catalyst is able not only to control the enantioselectivity but also to reverse the regioselectivity of the noncatalyzed nitroso-Diels-Alder reaction. The regiochemistry reversal and asynchronous concerted mechanism were confirmed by DFT calculations.

  6. Effects of humic acids, para-aminobenzoic acid and ascorbic acid on the N-nitrosation of the carbamate insecticide propoxur and on the mutagenicity of nitrosopropoxur. (United States)

    Gichner, T; Badaev, S A; Pospísil, F; Velemínský, J


    Nitrosation of the carbamate insecticide propoxur at pH 3 and 37 degrees C was determined colorimetrically and found to be time- and sodium nitrite concentration-dependent. Nitrosated propoxur was mutagenic when exposed to the seeds of the higher plant Arabidopsis thaliana but the formation of nitrosopropoxur, the presumed mutagen, was inhibited by humic acids, para-aminobenzoic acid and ascorbic acid. These agents also reduced the mutagenicity of preformed nitrosopropoxur.

  7. Supercritical fluid extraction for some carbamate insecticides in potatoes samples, with HPLC/fluorescence determination and HPLC/mass spectrometry confirmation


    Gilvanda Silva Nunes; Teresa Cristina R. Santos; Damiá Barceló; Alexandre Santos Pimenta; Maria Lúcia Ribeiro


    Six supercritical fluid extraction (SFE) methods were tested, by varying the following operational parameters: CO2 pressure, time and temperature of extraction, type and proportion of static modifier, and Hydromatrix®/sample rate into cell. Firstly, insecticide carbamates were extracted from spiked potatoes samples (fortification level of 0,5 mg.Kg-1) by using SPE procedures, and then final extracts were analyzed HPLC/fluorescence. Good performance was observed with SFE methods that operated ...

  8. Wild Raspberry Subjected to Simulated Gastrointestinal Digestion Improves the Protective Capacity against Ethyl Carbamate-Induced Oxidative Damage in Caco-2 Cells. (United States)

    Chen, Wei; Xu, Yang; Zhang, Lingxia; Li, Ya; Zheng, Xiaodong


    Ethyl carbamate (EC), a probable human carcinogen, occurs widely in many fermented foods. Previous studies indicated that EC-induced cytotoxicity was associated with oxidative stress. Wild raspberries are rich in polyphenolic compounds, which possess potent antioxidant activity. This study was conducted to investigate the protective effect of wild raspberry extracts produced before (RE) and after in vitro simulated gastrointestinal digestion (RD) on EC-induced oxidative damage in Caco-2 cells. Our primary data showed that ethyl carbamate could result in cytotoxicity and genotoxicity in Caco-2 cells and raspberry extract after digestion (RD) may be more effective than that before digestion (RE) in attenuating toxicity caused by ethyl carbamate. Further investigation by fluorescence microscope revealed that RD may significantly ameliorate EC-induced oxidative damage by scavenging the overproduction of intracellular reactive oxygen species (ROS), maintaining mitochondrial function and preventing glutathione (GSH) depletion. In addition, HPLC-ESI-MS results showed that the contents of identified polyphenolic compounds (esculin, kaempferol O-hexoside, and pelargonidin O-hexoside) were remarkably increased after digestion, which might be related to the better protective effect of RD. Overall, our results demonstrated that raspberry extract undergoing simulated gastrointestinal digestion may improve the protective effect against EC-induced oxidative damage in Caco-2 cells.

  9. A simple electrochemical biosensor based on AuNPs/MPS/Au electrode sensing layer for monitoring carbamate pesticides in real samples. (United States)

    Song, Yonghai; Chen, Jingyi; Sun, Min; Gong, Coucong; Shen, Yuan; Song, Yonggui; Wang, Li


    A simple electrochemical biosensor for quantitative determination of carbamate pesticide was developed based on a sensing interface of citrate-capped gold nanoparticles (AuNPs)/(3-mercaptopropyl)-trimethoxysilane (MPS)/gold electrode (Au). The biosensor was fabricated by firstly assembling three-dimensional (3D) MPS networks on Au electrode and subsequently assembling citrate-capped AuNPs on 3D MPS network via AuS bond. The interface of AuNPs/MPS/Au was negatively charged originating from the citrate coated on AuNPs that would repulse the negatively charged ferricyanide ([Fe(CN)6](3-/4-)) to produce a negative response. In the presence of acetylcholinesterase (AChE) and acetylthiocholine (ATCl), the AChE catalyzes the hydrolysis of ATCl into positively charged thiocholine which would replace the citrate on AuNPs through the strong AuS bond and convert the negative charged surface to be positively charged. The resulted positively charged AuNPs/MPS/Au then attracted the [Fe(CN)6](3-/4-) to produce a positive response. Based on the inhibition of carbamate pesticides on the activity of AChE, the pesticide could be quantitatively determined at a very low potential. The linear range was from 0.003 to 2.00 μM. The sensing platform was also proved to be suitable for carbamate pesticides detection in practical sample.

  10. Analysis of Carbamate Pesticides: Validation of Semi-Volatile Analysis by HPLC-MS/MS by EPA Method MS666

    Energy Technology Data Exchange (ETDEWEB)

    Owens, J; Koester, C


    The Environmental Protection Agency's (EPA) Region 5 Chicago Regional Laboratory (CRL) developed a method for analysis of aldicarb, bromadiolone, carbofuran, oxamyl, and methomyl in water by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS), titled Method EPA MS666. This draft standard operating procedure (SOP) was distributed to multiple EPA laboratories and to Lawrence Livermore National Laboratory, which was tasked to serve as a reference laboratory for EPA's Environmental Reference Laboratory Network (ERLN) and to develop and validate analytical procedures. The primary objective of this study was to validate and verify the analytical procedures described in MS666 for analysis of carbamate pesticides in aqueous samples. The gathered data from this validation study will be used to: (1) demonstrate analytical method performance; (2) generate quality control acceptance criteria; and (3) revise the SOP to provide a validated method that would be available for use during a homeland security event. The data contained in this report will be compiled, by EPA CRL, with data generated by other EPA Regional laboratories so that performance metrics of Method EPA MS666 can be determined.

  11. Design, synthesis, and biological evaluation of scutellarein carbamate derivatives as potential multifunctional agents for the treatment of Alzheimer's disease. (United States)

    Sang, Zhi-Pei; Qiang, Xiao-Ming; Li, Yan; Wu, Bei; Zhang, Hui; Zhao, Ming-Gao; Deng, Yong


    A series of scutellarein carbamate derivatives were designed and synthesized based on the multitarget-directed drug design strategy for treatment of Alzheimer's disease. Their acetylcholinesterase and butyrylcholinesterase inhibitory activities, antioxidant activities, metals chelation, and neuroprotective effects against hydrogen peroxide-induced PC12 cell injury were evaluated in vitro. The preliminary results indicated that compound 7b exhibited good inhibitory potency toward AChE and BuChE with IC50 values of 1.2 ± 0.03 μm and 22.1 ± 0.15 μm, respectively, possessed the strong antioxidant potency (10.3 trolox equivalents), as well as acted as a selective metal chelator and neuroprotective agent. Furthermore, 7b could improve memory impairment induced by scopolamine, ethanol, and sodium nitrite using the step-down passive avoidance task in vivo and could remarkably decrease the activity of acetylcholinesterase in mice brain. This study indicated that 7b could be considered as a potential multitarget agent against AD.

  12. The Stepwise Behavioral Responses: Behavioral Adjustment of the Chinese Rare Minnow (Gobiocypris rarus in the Exposure of Carbamate Pesticides

    Directory of Open Access Journals (Sweden)

    Zongming Ren


    Full Text Available In order to illustrate the behavioral regulation in environmental stress, the behavioral responses of the Chinese rare minnow (Gobiocypris rarus to arprocarb, carbofuran, and oxamyl were analyzed with an online monitoring system. The Self-Organizing Map (SOM was used to define the patterns of the behavioral data obtained from treatments at concentrations of 0.1 toxic unit (TU, 1 TU, 2 TU, 5 TU, 10 TU, and 20 TU and a control. In certain cases, differences among the carbamate pesticides (CPs tested were observed. The profiles of behavioral strength (BS in SOM varied according to the concentration used. The time of the first significant decrease of the BS varied inversely with the CP concentrations. The results suggested that the behavioral regulation in the stepwise behavioral responses (SBR was evident. The primary movement behaviors shown by the SBR model included no effect, stimulation, acclimation, adjustment (readjustment, and toxic effect, especially at the lower concentrations. However, higher stress (10 TU and 20 TU might limit the function of the behavioral adjustment produced by the intrinsic response mechanisms. It was concluded that SBR, which were affected by both the concentration and the exposure time, could be used as a suitable indicator in the ecotoxicological risk assessment of CPs.

  13. Increased Risk of Dementia in Patients With Acute Organophosphate and Carbamate Poisoning: A Nationwide Population-Based Cohort Study. (United States)

    Lin, Jiun-Nong; Lin, Cheng-Li; Lin, Ming-Chia; Lai, Chung-Hsu; Lin, Hsi-Hsun; Yang, Chih-Hui; Kao, Chia-Hung


    Organophosphate (OP) and carbamate (CM) are the most commonly used pesticides against insects. Little is known regarding the relationship between dementia and acute OP and CM poisoning. A nationwide population-based cohort study was conducted from the National Health Insurance Research Database in Taiwan. The incidence and relative risk of dementia were assessed in patients hospitalized for acute OP and CM poisoning from 2000 to 2011. The comparison cohort was matched with the poisoned cohort at a 4:1 ratio based on age, sex, and the year of hospitalization. During the follow-up period, the incidence of dementia was 29.4 per 10,000 person-years in the poisoned group, and represented a 1.98-fold increased risk of dementia compared with the control cohort (95% confidence interval, 1.59-2.47). This study provides evidence on the association between dementia and acute OP and CM poisoning. Regular follow-up of poisoned patients for dementia is suggested.

  14. Detecting resistance to organophosphates and carbamates in the cattle tick Boophilus microplus, with a propoxur-based biochemical test. (United States)

    Baxter, G D; Green, P; Stuttgen, M; Barker, S C


    Rapid and sensitive detection of resistance to insecticides in arthropods is needed. In the cattle tick. Boophilus microplus, resistance to a variety of acaricides is widespread. The most commonly used assay for resistance, the larval packet test, takes at least two, but generally six weeks for a one-host tick like B. microplus to complete and may take up to three months to complete for three-host ticks. Here we describe a test for resistance to organophosphate acaricides that can be used on larvae and adult ticks which takes less than 24 hours. The test measures the difference in acetylcholinesterase (AChE) activity in homogenates of ticks in the presence and absence of propoxur, a carbamate acaricide. We found clear discrimination of organophosphate-susceptible and organophosphate-resistant adults with 100 microM propoxur. AChE from susceptible ticks had almost no activity at this concentration of propoxur whereas AChE from resistant ticks had 67% of its potential activity. AChE from heterozygote ticks could also be distinguished from AChE from homozygous-susceptible and homozygous-resistant ticks. This is the first biochemical test for resistance to an acaricide. Rapid, sensitive tests like ours will allow resistance to organophosphates to be detected soon after it develops in the field, thus, the spread of resistance might be slowed and the useful life of acaricides extended.

  15. The use of carbamates, atropine, and 2-pyridine aldoxime methoiodide in the protection of Artemia salina against poisoning by carbophenothion. (United States)

    Sánchez-Fortún, S; Barahona, V


    The acute toxicity of carbophenothion to three age classes of Artemia salina was evaluated. An increase in toxicity of carbophenothion was found following longer development of A. salina. The effect of pretreatment with the nonselective muscarinic antagonist atropine, the two reversible acetylcholinesterase-inhibitors physostigmine and pyridostigmine, and the cholinesterase-reactivating oxime 2-pyridine aldoxime methochloride (2-PAM) on carbophenothion-induced lethality in 24-h-old A. salina was also investigated. The lethal action of carbophenothion was completely prevented by pretreatment of A. salina with 2-PAM. Atropine and pyridostigmine afforded a maximal protection of approximately 87% and 72%, respectively, compared to control values. In contrast, physostigmine was ineffective. The inhibitory effects of combinations of 10(-5) M atropine with physostigmine, pyridostigmine, or 2-PAM were greater than those elicited by either drug alone, with the maximum protection afforded being 92.58%, 100%, and 100%, respectively. In the presence of 10(-7) M atropine, neither pyridostigmine nor 2-PAM provided additional inhibition of the lethality compared to that with either drug alone, whereas the protection afforded by 10(-7) M atropine plus physostigmine increased as the concentration of carbamate increased (up to 10(-3) M). Pretreatment with pyridostigmine or physostigmine plus 2-PAM (10(-6) M) slightly enhanced the maximal inhibition of carbophenothion lethality compared to that with either drug alone. It is suggested that the most active combined pretreatment studied here was physostigmine plus atropine.

  16. Use of an ionic liquid-based surfactant as pseudostationary phase in the analysis of carbamates by micellar electrokinetic chromatography. (United States)

    Tejada-Casado, Carmen; Moreno-González, David; García-Campaña, Ana M; del Olmo-Iruela, Monsalud


    The applicability of an ionic liquid-based cationic surfactant 1-dodecyl-3-methyl-imidazolium tetrafluoroborate (C12 MImBF4 ) as pseudostationary phase in MEKC has been evaluated for the analysis of 11 carbamate pesticides (promecarb, carbofuran, metolcarb, fenobucarb, aldicarb, propoxur, asulam, benomyl, carbendazim, ethiofencarb, isoprocarb) in juice samples. Under optimum conditions (separation buffer, 35 mM NaHCO3 and 20 mM C12 MImBF4 , pH 9.0; capillary temperature 25°C; voltage -22 kV) the analysis was carried out in less than 12 min, using hydrodynamic injection (50 mbar for 7.5 s) and detection at 200 nm. For the extraction of these CRBs from juice samples, a dispersive liquid-liquid microextraction (DLLME) procedure has been proposed, by optimization of variables affecting the efficiency of the extraction. Following this treatment, sample throughput was approximately 12 samples per hour, obtaining a preconcentration factor of 20. Matrix-matched calibration curves were established using tomato juice as representative matrix (from 5 to 250 μg/L for CBZ, BY, PX, CF, FEN, ETH, ISP, and 25-250 μg/L for ASL, ALD, PRC, MTL), obtaining quantification limits ranging from 1 to 18 μg/L and recoveries from 70 to 96%, with RSDs lower than 9%.

  17. Studies on the Purification and Characterization of Soybean Esterase,and Its Sensitivity to Organophosphate and Carbamate Pesticides

    Institute of Scientific and Technical Information of China (English)

    LI Jian-ke; ZHOU Yan-li; WEN Yan-xia; WANG Jian-hua; HU Qiu-hui


    Soybean esterase,a cholinesterase-like enzyme,was purified by differential centrifugation firstly,then,ammonium sulfate precipitation,dialysis,and finally,DEAE-cellulose-32 ion-exchange chromatography after extracting it from soybean seeds with phosphate buffer(0.3 mol L-1,pH 7.0).The extract recovery rate of the purified enzyme was 8.18% and purification fold was 91.58.The soybean esterase appeared as two bands on the denaturing SDS-PAGE with molecular weights of 24 and 37.2 kDa,respectively,which proved that it is a dimer protein consisting of two subunits.The result of nondenaturing PAGE revealed that the soybean esterase is a single band with cholinesterase-like activity using α-naphthyl acetate as the substrate and fast blue B salt as coloring agent.The esterase showed very high sensitivity to 18 kinds of organophosphate pesticides and 6 kinds of carbamate pesticides with the lowest detective limits of 0.03125-0.0625 and 0.03 125-0.25 mg kg-1,respectively,and can meet the demands of MRL specified by the most countries.

  18. Chromogenic platform based on recombinant Drosophila melanogaster acetylcholinesterase for visible unidirectional assay of organophosphate and carbamate insecticide residues

    Energy Technology Data Exchange (ETDEWEB)

    Han Zheng [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Chi Chensen [School of Life Science and Biotechnology, Bor Luh Food Safety Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Bai Bing; Liu Gang; Rao Qinxiong [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Peng Shaojie [Institute of Shanghai Food and Drug Supervision, 615 Liuzhou Road, Shanghai 200233 (China); Liu Hong [Shanghai Municipal Center for Disease Control and Prevention, 1380 Zhongshan West Road, Shanghai 200336 (China); Zhao Zhihui [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China); Zhang Dabing [School of Life Science and Biotechnology, Bor Luh Food Safety Center, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240 (China); Wu Aibo, E-mail: [Institute for Agri-food Standards and Testing Technology, Shanghai Academy of Agricultural Sciences, 1018 Jinqi Road, Shanghai 201403 (China)


    Highlight: Black-Right-Pointing-Pointer A visible chromogenic platform for rapid analysis of OP and CM insecticide residues was developed. Black-Right-Pointing-Pointer The assay has the capabilities of both qualitative measurement and quantitative analysis. Black-Right-Pointing-Pointer The sensitivity, capabilities of resisting interferences and storage stability were desirable. Black-Right-Pointing-Pointer Matrix effects were acceptable and detection performance was satisfactory in real application. - Abstract: In this study we propose a chromogenic platform for rapid analysis of organophosphate (OP) and carbamate (CM) insecticide residues, based on recombinant Drosophila melanogaster acetylcholinesterase (R-DmAChE) as enzyme and indoxyl acetate as substrate. The visible chromogenic strip had the advantages identical to those of commonly used lateral flow assays (LFAs) with utmost simplicity in sample loading and result observation. After optimization, depending on the color intensity (CI) values, the well-established assay has the capabilities of both qualitative measurement via naked eyes and quantitative analysis by colorimetric reader with the desirable IC{sub 50} values against the tested six insecticides (0.06 {mu}g mL{sup -1} of carbofuran, 0.28 {mu}g mL{sup -1} of methomyl, 0.03 {mu}g mL{sup -1} of dichlorvos, 31.6 {mu}g mL{sup -1} of methamidophos, 2.0 {mu}g mL{sup -1} of monocrotophos, 6.3 {mu}g mL{sup -1} of omethoate). Acceptable matrix effects and satisfactory detection performance were confirmed by in-parallel LC-MS/MS analysis in different vegetable varieties at various spiked levels of 10{sup -3} to 10{sup 1} {mu}g g{sup -1}. Overall, the testified suitability and applicability of this novel platform meet the requirements for practical use in food safety management and environmental monitoring, especially in the developing world.

  19. [Simultaneous determination of ethyl carbamate and chloropropanols in flavorings by gas chromatography-triple quadrupole tandem mass spectrometry]. (United States)

    Xu, Xiaomin; He, Huali; Ruan, Yudi; Huang, Baifen; Zhang, Jingshun; Cai, Zengxuan; Ren, Yiping


    A simultaneous determination method for ethyl carbamate (EC) and chloropropanols (3-monochloropropane-1, 2-diol (3-MCPD) and 2-monochloropropane-1, 3-diol (2-MCPD)) in flavorings was developed by gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). After spiked with internal standard, the sample was extracted by matrix solid-phase dispersion extraction technique with an Extrelut NT column. Hexane was used to wash the fat soluble matrix interferences and then an ethyl acetate-ethyl ether (20: 80, v/v) mixture was added to elute the analytes. The concentrated extract was detected by GC-MS/MS in multiple reaction monitoring (MRM) mode. The limits of detection (LODs) were 2, 5 and 5 microg/kg for EC, 3-MCPD and 2-MCPD, respectively. The linear ranges were 5 - 1 000 microg/kg (r = 0.9997), 10-1000 microg/kg (r = 0.999 1) and 10-1000 microg/kg (r = 0.999 5) for EC, 3-MCPD and 2-MCPD, respectively. In soy sauce, yellow rice wine, salami sauce and flavoring of instant noodle matrices, the recoveries (RSDs, n = 7) in MRM mode at the levels of 20, 100 and 400 microg/kg were 87.7%-104% (4.3%-10.7%), 90.1%-109% (2.6%-10.2%), and 90.9%-103% (3.0%-9.5%), respectively. EC, 3-MCPD and 2-MCPD were found in some real samples of the soy sauce, wine and flavoring of instant noodle. EC or 3-MCPD was found in some of the salami samples. The method is accurate, fast and suitable for the simultaneous determination of EC, 3-MCPD and 2-MCPD in flavorings.

  20. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory; determination of selected carbamate pesticides in water by high-performance liquid chromatography (United States)

    Werner, S.L.; Johnson, S.M.


    As part of its primary responsibility concerning water as a national resource, the U.S. Geological Survey collects and analyzes samples of ground water and surface water to determine water quality. This report describes the method used since June 1987 to determine selected total-recoverable carbamate pesticides present in water samples. High- performance liquid chromatography is used to separate N-methyl carbamates, N-methyl carbamoyloximes, and an N-phenyl carbamate which have been extracted from water and concentrated in dichloromethane. Analytes, surrogate compounds, and reference compounds are eluted from the analytical column within 25 minutes. Two modes of analyte detection are used: (1) a photodiode-array detector measures and records ultraviolet-absorbance profiles, and (2) a fluorescence detector measures and records fluorescence from an analyte derivative produced when analyte hydrolysis is combined with chemical derivatization. Analytes are identified and confirmed in a three-stage process by use of chromatographic retention time, ultraviolet (UV) spectral comparison, and derivatization/fluorescence detection. Quantitative results are based on the integration of single-wavelength UV-absorbance chromatograms and on comparison with calibration curves derived from external analyte standards that are run with samples as part of an instrumental analytical sequence. Estimated method detection limits vary for each analyte, depending on the sample matrix conditions, and range from 0.5 microgram per liter to as low as 0.01 microgram per liter. Reporting levels for all analytes have been set at 0.5 microgram per liter for this method. Corrections on the basis of percentage recoveries of analytes spiked into distilled water are not applied to values calculated for analyte concentration in samples. These values for analyte concentrations instead indicate the quantities recovered by the method from a particular sample matrix.

  1. [Determination of 51 carbamate pesticide residues in vegetables by liquid chromatography-tandem mass spectrometry based on optimization of QuEChERS sample preparation method]. (United States)

    Wang, Lianzhu; Zhou, Yu; Huang, Xiaoyan; Wang, Ruilong; Lin, Zixu; Chen, Yong; Wang, Dengfei; Lin, Dejuan; Xu, Dunming


    The raw extracts of six vegetables (tomato, green bean, shallot, broccoli, ginger and carrot) were analyzed using gas chromatography-mass spectrometry (GC-MS) in full scan mode combined with NIST library search to confirm main matrix compounds. The effects of cleanup and adsorption mechanisms of primary secondary amine (PSA) , octadecylsilane (C18) and PSA + C18 on co-extractives were studied by the weight of evaporation residue for extracts before and after cleanup. The suitability of the two versions of QuEChERS method for sample preparation was evaluated for the extraction of 51 carbamate pesticides in the six vegetables. One of the QuEChERS methods was the original un-buffered method published in 2003, and the other was AOAC Official Method 2007.01 using acetate buffer. As a result, the best effects were obtained from using the combination of C18 and PSA for extract cleanup in vegetables. The acetate-buffered version was suitable for the determination of all pesticides except dioxacarb. Un-buffered QuEChERS method gave satisfactory results for determining dioxacarb. Based on these results, the suitable QuEChERS sample preparation method and liquid chromatography-positive electrospray ionization-tandem mass spectrometry under the optimized conditions were applied to determine the 51 carbamate pesticide residues in six vegetables. The analytes were quantified by matrix-matched standard solution. The recoveries at three levels of 10, 20 and 100 microg/kg spiked in six vegetables ranged from 58.4% to 126% with the relative standard deviations of 3.3%-26%. The limits of quantification (LOQ, S/N > or = 10) were 0.2-10 microg/kg except that the LOQs of cartap and thiofanox were 50 microg/kg. The method is highly efficient, sensitive and suitable for monitoring the 51 carbamate pesticide residues in vegetables.

  2. Fluorescence biosensing strategy based on mercury ion-mediated DNA conformational switch and nicking enzyme-assisted cycling amplification for highly sensitive detection of carbamate pesticide. (United States)

    Wang, Xiuzhong; Hou, Ting; Dong, Shanshan; Liu, Xiaojuan; Li, Feng


    Pesticides are of great importance in agricultural and biological fields, but pesticide residues may harm the environment and human health. A highly sensitive fluorescent biosensor for the detection of carbamate pesticide has been developed based on acetylcholinesterase (AChE)-catalyzed hydrolysis product triggered Hg(2+) release coupled with subsequent nicking enzyme-induced cleavage of a duplex DNA for cycling amplification. In this protocol, two DNA probes, an unmodified single-stranded helper DNA probe 1 (HP1) and a quencher-fluorophore probe (QFP) are ingeniously designed. HP1 can be folded into hairpin configuration through T-Hg(2+)-T base pair formation. QFP, labeled with FAM and BHQ1 at its two terminals, contains the recognition sequence and the cleavage site of the nicking enzyme. In the presence of carbamate pesticide, the activity of AChE is inhibited, and the amount of the product containing the thiol group generated by the hydrolysis reaction of acetylthiocholine chloride (ACh) decreases, resulting in the release of a low concentration of Hg(2+). The number of HP1 that can be selectively unfolded would be reduced and the subsequent nicking enzyme-assisted cleavage processes would be affected, resulting in decreased fluorescence signals. The fluorescence intensity further decreases with the increase of the pesticide concentration. Therefore, the pesticide content can be easily obtained by monitoring the fluorescence signal change, which is inversely proportional to the logarithm of the pesticide concentration. The detection limit of aldicarb, the model analyte, is 3.3 μgL(-1), which is much lower than the Chinese National Standards or those previously reported. The as-proposed method has also been applied to detect carbamate pesticide residues in fresh ginger and artificial lake water samples with satisfactory results, which demonstrates that the method has great potential for practical application in biological or food safety field.

  3. Hypervalent iodine(iii)-promoted N-incorporation into N-aryl vinylogous carbamates to quinoxaline diesters: access to 1,4,5,8-tetraazaphenanthrene. (United States)

    Sagar, A; Vidaycharan, Shinde; Shinde, Anand H; Sharada, Duddu S


    A novel oxidative N-incorporation strategy for synthesis of quinoxaline diesters under metal-free conditions is described for the first time. The mild reaction conditions allow for this transformation via the formation of two C(sp(2))-N bonds utilizing cheaply available NaN3 as the N-atom source. N-Aryl vinylogous carbamates in this study undergo azidation at enamino C(sp(2))-H selectively. The robustness of this strategy is further demonstrated by the synthesis of a valuable 1,4,5,8-tetraazaphenanthrene derivative using a mild and convenient approach.

  4. (1)H NMR-based metabonomic profiling of rat serum and urine to characterize the subacute effects of carbamate insecticide propoxur. (United States)

    Liang, Yu-Jie; Wang, Hui-Ping; Long, Ding-Xin; Wu, Yi-Jun


    Carbamate insecticide propoxur is widely used in agriculture and public health programs. To prevent adverse health effects arising from exposure to this insecticide, sensitive methods for detection of early stage organismal changes are necessary. We present here an integrative metabonomic approach to investigate toxic effects of pesticide in experimental animals. Results showed that propoxur even at low dose levels can induce oxidative stress, impair liver function, enhance ketogenesis and fatty acid β-oxidation, and increase glycolysis, which contribute to the hepatotoxocity. These findings highlight the applicability of (1)H NMR spectroscopy and multivariate statistics in elucidating the toxic effects of propoxur.

  5. Distribution of ace-1R and resistance to carbamates and organophosphates in Anopheles gambiae s.s. populations from Côte d'Ivoire

    Directory of Open Access Journals (Sweden)

    Ahoua Alou Ludovic P


    Full Text Available Abstract Background The spread of pyrethroid resistance in Anopheles gambiae s.s. is a critical issue for malaria vector control based on the use of insecticide-treated nets. Carbamates and organophosphates insecticides are regarded as alternatives or supplements to pyrethroids used in nets treatment. It is, therefore, essential to investigate on the susceptibility of pyrethroid resistant populations of An. gambiae s.s. to these alternative products. Methods In September 2004, a cross sectional survey was conducted in six localities in Côte d'Ivoire: Toumbokro, Yamoussoukro, Toumodi in the Southern Guinea savannah, Tiassalé in semi-deciduous forest, then Nieky and Abidjan in evergreen forest area. An. gambiae populations from these localities were previously reported to be highly resistant to pyrethroids insecticides. Anopheline larvae were collected from the field and reared to adults. Resistance/susceptibility to carbamates (0.4% carbosulfan, 0.1% propoxur and organophosphates (0.4% chlorpyrifos-methyl, 1% fenitrothion was assessed using WHO bioassay test kits for adult mosquitoes. Then, PCR assays were run to determine the molecular forms (M and (S, as well as phenotypes for insensitive acetylcholinesterase (AChE1 due to G119S mutation. Results Bioassays showed carbamates (carbosulfan and propoxur resistance in all tested populations of An. gambiae s.s. In addition, two out of the six tested populations (Toumodi and Tiassalé were also resistant to organophosphates (mortality rates ranged from 29.5% to 93.3%. The M-form was predominant in tested samples (91.8%. M and S molecular forms were sympatric at two localities but no M/S hybrids were detected. The highest proportion of S-form (7.9% of An. gambiae identified was in sample from Toumbokro, in the southern Guinea savannah. The G119S mutation was found in both M and S molecular forms with frequency from 30.9 to 35.2%. Conclusion This study revealed a wide distribution of insensitive

  6. Assessing the Potential Content of Ethyl Carbamate in White, Red, and Rosé Wines as a Key Factor for Pursuing Urea Degradation by Purified Acid Urease. (United States)

    Cerreti, Martina; Fidaleo, Marcello; Benucci, Ilaria; Liburdi, Katia; Tamborra, Pasquale; Moresi, Mauro


    The ethyl carbamate (EC) content of a wine after a given temperature-time storage was theoretically predicted from the potential concentration of ethyl carbamate (PEC), as determined via an accelerated EC formation test. Such information was used to decide whether an enzymatic treatment was needed to reduce the wine urea level before bottling/aging. To this end, 6 white, red, and rosé wines, manufactured in Italy as such or enriched with urea, were tested for their PEC content either before or after enzymatic treatment using a purified acid urease preparation derived from Lactobacillus fermentum. The treatment was severely affected by the total phenolic content (TP) of the wine, the estimated pseudo-first-order kinetic rate constant for NH3 formation reducing by a factor of approximately 2000 as the TP increased from 0 to 1.64 g L(-1) . Such a sensitivity to TP was by far greater than that pertaining to a killed cell-based enzyme preparation used previously. Urea hydrolysis was successful at reducing EC concentration in wines with low levels of TP and other EC precursors.

  7. Co(II), Ni(II) and Cu(II) complexes of methyl-5-(Phenylthio) benzimidazole-2-carbamate: Molecular structures, spectral and DFT calculations (United States)

    Mansour, Ahmed M.; El Bakry, Eslam M.; Abdel-Ghani, Nour T.


    [Co(FBZ)2(H2O)]·2NO3·0.5H2O (1), [Ni(FBZ)2X2]·zH2O (X = Cl​-, z = 0.5 (2) and X = CH3COO-, z = 1 (3)) and [Cu(FBZ)2(H2O) (NO3)]·NO3·1.5H2O (4) (FBZ = methyl-5-(Phenylthio) benzimidazole-2-carbamate; Fenbendazole) complexes were synthesized and characterized by elemental analysis, thermal, IR, EPR, UV-Vis, magnetic and conductance measurements. Geometry optimization, molecular electrostatic potential maps and natural bond orbital analysis were carried out at DFT/B3LYP/6-31G∗ level of theory. FBZ behaves as a neutral bidentate ligand via the pyridine-type nitrogen of the benzimidazole moiety and the carbamate group. Three-step ionization with pKa values of 3.38, 4.06 and 10.07 were reported for FBZ. The coordination of FBZ to the metal ions led to an increase in the antibacterial activity against the tested Staphylococcus aureus and Escherichia coli bacteria.

  8. Ionic liquid polymer functionalized carbon nanotubes-doped poly(3,4-ethylenedioxythiophene) for highly-efficient solid-phase microextraction of carbamate pesticides. (United States)

    Wu, Mian; Wang, Liying; Zeng, Baizhao; Zhao, Faqiong


    A poly(3,4-ethylenedioxythiophene)-ionic liquid polymer functionalized multiwalled carbon nanotubes (PEDOT-PIL/MWCNTs) composite solid-phase microextraction (SPME) coating was fabricated by electrodeposition. After being dipped in Nafion solution, a Nafion-modified coating was obtained. The outer layer Nafion played a crucial role in enhancing the durability and stability of the coating, thus it was robust enough for replicated extraction for at least 150 times without decrease of extraction performance. The Nafion-modified coating exhibited much higher sensitivity than commercial coatings for the direct extraction of carbamate pesticides in aqueous solutions, due to its strong hydrophobic effect and π-π affinity based enrichment. When it was used for the determination of carbamate pesticides in combination with gas chromatography-flame ionization detection, good linearity (correlation coefficients higher than 0.9981), low limits of detection (15.2-27.2 ng/L) and satisfactory precision (relative standard deviation pesticides in apple and lettuce samples, and acceptable recoveries (i.e. 87.5-106.5%) were obtained for the standard addition.

  9. A mutant beta-tubulin confers resistance to the action of benzimidazole-carbamate microtubule inhibitors both in vivo and in vitro. (United States)

    Foster, K E; Burland, T G; Gull, K


    The mutant BEN210 of Physarum polycephalum is highly resistant to a number of benzimidazole carbamate agents, including methylbenzimidazole-2-yl-carbamate and parbendazole. The resistance is conferred by the benD210 mutation in a structural gene for beta-tubulin. This mutant allele encodes a beta-tubulin with novel electrophoretic mobility. We have used this strain to determine whether the mutant beta-tubulin is used in microtubules and whether this usage permits microtubule polymerisation in the presence of drugs both in vivo and in vitro. In vitro assembly studies of tubulin purified from the mutant strain have shown that microtubules are formed both in the absence of drugs and in all drug concentrations tested (up to 50 microM parbendazole). In contrast, the assembly of microtubules from wild-type tubulin in vitro is totally inhibited by 2-5 microM parbendazole. Thus the resistance of BEN210 to parbendazole observed in vivo has been reproduced in vitro using tubulin purified from the mutant strain. Electrophoretic analysis of the microtubules formed in vitro has shown that both the wild-type and the mutant beta-tubulin are incorporated into the microtubules and that the proportion of mutant to wild-type beta-tubulin appears to remain constant with increasing drug concentration. This is the first demonstration of a single mutation in a tubulin structural gene causing an altered function of the gene product in vitro.

  10. Sequential injection kinetic spectrophotometric determination of quaternary mixtures of carbamate pesticides in water and fruit samples using artificial neural networks for multivariate calibration (United States)

    Chu, Ning; Fan, Shihua


    A new analytical method was developed for the simultaneous kinetic spectrophotometric determination of a quaternary carbamate pesticide mixture consisting of carbofuran, propoxur, metolcarb and fenobucarb using sequential injection analysis (SIA). The procedure was based upon the different kinetic properties between the analytes reacted with reagent in flow system in the non-stopped-flow mode, in which their hydrolysis products coupled with diazotized p-nitroaniline in an alkaline medium to form the corresponding colored complexes. The absorbance data from SIA peak time profile were recorded at 510 nm and resolved by the use of back-propagation-artificial neural network (BP-ANN) algorithms for multivariate quantitative analysis. The experimental variables and main network parameters were optimized and each of the pesticides could be determined in the concentration range of 0.5-10.0 μg mL -1, at a sampling frequency of 18 h -1. The proposed method was compared to other spectrophotometric methods for simultaneous determination of mixtures of carbamate pesticides, and it was proved to be adequately reliable and was successfully applied to the simultaneous determination of the four pesticide residues in water and fruit samples, obtaining the satisfactory results based on recovery studies (84.7-116.0%).

  11. Human plasma concentrations of herbicidal carbamate molinate extrapolated from the pharmacokinetics established in in vivo experiments with chimeric mice with humanized liver and physiologically based pharmacokinetic modeling. (United States)

    Yamashita, Masanao; Suemizu, Hiroshi; Murayama, Norie; Nishiyama, Sayako; Shimizu, Makiko; Yamazaki, Hiroshi


    To predict concentrations in humans of the herbicidal carbamate molinate, used exclusively in rice cultivation, a forward dosimetry approach was carried out using data from lowest-observed-adverse-effect-level doses orally administered to rats, wild type mice, and chimeric mice with humanized liver and from in vitro human and rodent experiments. Human liver microsomes preferentially mediated hydroxylation of molinate, but rat livers additionally produced molinate sulfoxide and an unidentified metabolite. Adjusted animal biomonitoring equivalents for molinate and its primary sulfoxide from animal studies were scaled to human biomonitoring equivalents using known species allometric scaling factors and human metabolic data with a simple physiologically based pharmacokinetic (PBPK) model. The slower disposition of molinate and accumulation of molinate sulfoxide in humans were estimated by modeling after single and multiple doses compared with elimination in rodents. The results from simplified PBPK modeling in combination with chimeric mice with humanized liver suggest that ratios of estimated parameters of molinate sulfoxide exposure in humans to those in rats were three times as many as general safety factor of 10 for species difference in toxicokinetics. Thus, careful regulatory decision is needed when evaluating the human risk resulting from exposure to low doses of molinate and related carbamates based on data obtained from rats.

  12. Novel method for the determination of five carbamate pesticides in water samples by dispersive liquid-liquid microextraction combined with high performance liquid chromatography

    Institute of Scientific and Technical Information of China (English)

    Zhi Mei Liu; Xiao Huan Zang; Wei Hua Liu; Chun Wang; Zhi Wang


    A novel method for the determination of five carbamate pesticides(metolcarb,carbofuran,carbaryl,isoprocard and diethofencard)in water samples was developed by dispersive liquid-liquid microextraction(DLLME)coupled with high performance liquid chromatography-diode array detector(HPLC-DAD).Some experimental parameters that influence the extraction efficiency were studied and optimized to obtain the best extraction results.Under the optimum conditions for the method,the calibration curve was linear in the concentration range from 5 to I000 ng mL-1 for all the five carbamate pesticides,with the correlation coefficients(r2)varying from 0.9984 to 0.9994.Good enrichment factors were achieved ranging from 80 to 177-fold,depending on the compound.The limits of detection(LODs)(S/N = 3)were ranged from 0.1 to 0.5 ng mL-1.The method has been successfully applied to the analysis of the pesticide residues in environmental water samples.

  13. Vortex-Assisted Dispersive Micro-Solid Phase Extraction Using CTAB-Modified Zeolite NaY Sorbent Coupled with HPLC for the Determination of Carbamate Insecticides. (United States)

    Salisaeng, Pawina; Arnnok, Prapha; Patdhanagul, Nopbhasinthu; Burakham, Rodjana


    A vortex-assisted dispersive micro-solid phase extraction (VA-D-μ-SPE) based on cetyltrimethylammonium bromide (CTAB)-modified zeolite NaY was developed for preconcentration of carbamate pesticides in fruits, vegetables, and natural surface water prior to analysis by high performance liquid chromatography with photodiode array detection. The small amounts of solid sorbent were dispersed in a sample solution, and extraction occurred by adsorption in a short time, which was accelerated by vortex agitation. Finally, the sorbents were filtered from the solution, and the analytes were subsequently desorbed using an appropriate solvent. Parameters affecting the VA-D-μ-SPE performance including sorbent amount, sample volume, desorption solvent ,and vortex time were optimized. Under the optimum condition, linear dynamic ranges were achieved between 0.004-24.000 mg kg(-1) (R(2) > 0.9946). The limits of detection (LODs) ranged from 0.004-4.000 mg kg(-1). The applicability of the developed procedure was successfully evaluated by the determination of the carbamate residues in fruits (dragon fruit, rambutan, and watermelon), vegetables (cabbage, cauliflower, and cucumber), and natural surface water.

  14. Determination of poorly fluorescent carbamate pesticides in water, bendiocarb and promecarb, using cyclodextrin nanocavities and related media

    Energy Technology Data Exchange (ETDEWEB)

    Pacioni, Natalia L. [Instituto de Investigaciones en Fisico Quimica de Cordoba (INFIQC), Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina); Veglia, Alicia V. [Instituto de Investigaciones en Fisico Quimica de Cordoba (INFIQC), Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba, Ciudad Universitaria, 5000 Cordoba (Argentina)]. E-mail:


    The effect of native cyclodextrins ({alpha}, {beta}, or {gamma}CD with six, seven and eight glucose units, respectively), hydroxypropyl-{beta}-cyclodextrin (HPCD), chitosan (CHT) and glucose in water solution or water with n-propylamine (PA) as co-solvent upon the UV-vis and fluorescence properties of poorly fluorescent N-methyl carbamates pesticides (C) as bendiocarb (2,2-dimethyl-1,3-benzodioxol-4-ol methylcarbamate, BC) and promecarb (3-methyl-5-(1-methylethyl)phenol methylcarbame, PC) was examined. Fluorescent enhancement was found for both substrates with all CDs in water or PA-water except from PC with {alpha}CD. The addition of CHT increases the fluorescence of BC but decreases the fluorescence of PC, and glucose addition gives in both cases no spectral changes. Host-guest interaction was clearly determined by fluorescence enhancement with {beta}CD and HPCD with a 1:1 stoichiometry for the complexes (C:CD). The values obtained for the association constants (K {sub A}, M{sup -1}) were (6 {+-} 2) x 10{sup 2} and (2.3 {+-} 0.3) x 10{sup 2} for BC:{beta}CD and BC:HPCD complexes, respectively. For PC:{beta}CD and PC:HPCD the values of K {sub A} were (19 {+-} 2) x 10{sup 2} and (21 {+-} 2) x 10{sup 2}, respectively. The ratio of the fluorescence quantum yields for the bound and free substrates ({phi} {sup CCD}/{phi} {sup C}) was in the range 1.74-3.8. The limits of detection (L {sub D}, {mu}g mL{sup -1}) for the best conditions were (0.57 {+-} 0.02) for BC with HPCD and (0.091 {+-} 0.002) for PC with {beta}CD in water. Application to the analysis in pesticide spiked samples of tap water and fruit yields satisfactory apparent recoveries (84-114%), and for the extraction procedure in fruits and a commercial formulation, recoveries were of 81-98% and 104%, respectively. The method is rapid, simple, direct, sensitive and useful for pesticide analysis.

  15. From greenhouse gas to feedstock: formation of ammonium carbamate from CO{sub 2} and NH{sub 3} in organic solvents and its catalytic conversion into urea under mild conditions

    Energy Technology Data Exchange (ETDEWEB)

    Barzagli, F.; Mani, F.; Peruzzini, M. [University of Florence, Florence (Italy). Dept. of Chemistry


    The capture of carbon dioxide by ammonia in both aqueous and non-aqueous solutions was investigated at atmospheric pressure and 273 K under different operating conditions. The CO{sub 2} capture is fast and efficient ranging between 78 and 99%, depending on both the NH{sub 3} concentration and the solvent nature. The precipitation of solid mixtures of ammonium bicarbonate, ammonium carbonate and ammonium carbamate occurred in ethanol-water solution. Selective precipitation of ammonium carbamate was achieved by reacting gaseous CO{sub 2} and NH{sub 3} in anhydrous ethanol, 1-propanol or N,N-dimethylformamide (DMF) in a flow reactor that operates in continuous. In the second step of the process, the pure ammonium carbamate is used to produce urea with good yield (up to 54% on carbamate basis) at 393-413 K in the presence of inexpensive Cu(II) and Zn(II) catalysts. The yield of urea depends on several factors including the catalyst, the reaction temperature and the reaction time. Identification and quantification of urea in the reaction mixtures was obtained by analysis of its {sup 13}C NMR spectrum. A preliminary mechanistic interpretation of the catalytic reaction is also briefly presented and commented.

  16. Organophosphorus and Carbamate Pesticide Residues Detected in Water Samples Collected from Paddy and Vegetable Fields of the Savar and Dhamrai Upazilas in Bangladesh

    Directory of Open Access Journals (Sweden)

    Nurul Karim


    Full Text Available Several types of organophosphorous and carbamate pesticides have been used extensively by the farmers in Bangladesh during the last few decades. Twenty seven water samples collected from both paddy and vegetable fields in the Savar and Dhamrai Upazilas in Bangladesh were analyzed to determine the occurrence and distribution of organo-phosphorus (chlorpyrifos, malathion and diazinon and carbamate (carbaryl and carbofuran pesticide residues. A high performance liquid chromatograph instrument equipped with a photodiode array detector was used to determine the concentrations of these pesticide residues. Diazinon and carbofuran were detected in water samples collected from Savar Upazila at 0.9 μg/L and 198.7 μg/L, respectively. Malathion was also detected in a single water sample at 105.2 μg/L from Dhamrai Upazila. Carbaryl was the most common pesticide detected in Dhamrai Upazila at 14.1 and 18.1 μg/L, while another water sample from Dhamrai Upazila was contaminated with carbofuran at 105.2 μg/L. Chlorpyrifos was not detected in any sample. Overall, the pesticide residues detected were well above the maximum acceptable levels of total and individual pesticide contamination, at 0.5 and 0.1 μg/L, respectively, in water samples recommended by the European Economic Community (Directive 98/83/EC. The presence of these pesticide residues may be attributed by their intense use by the farmers living in these areas. Proper handling of these pesticides should be ensured to avoid direct or indirect exposure to these pesticides.

  17. Curtius rearrangement reactions of 3-(4-azidocarbonyl) phenylsydnone. Synthesis of 4-(sydnon-3-yl) phenyl carbamates, N-aryl-N'-[4-(sydnon-3-yl)] phenyl ureas and their antimicrobial and insecticidal activities

    Indian Academy of Sciences (India)

    P R Latthe; P S Shinge; Bharati V Badami; P B Patil; S N Holihosur


    3-[4-(Azidocarbonyl)]phenylsydnone (2) obtained from 3-(4-hydrazinocarbonyl) phenylsydnone (1) on Curtius rearrangement with alcohols, water and amines afforded the corresponding carbamates (3a-h), 4,4'-(sydnone-3-yl) diphenyl urea (4) and 4-(heterocyclyl)phenyl ureas (5a-l). Compounds (5a-l) on one-pot ring conversion yielded the 1,3,4-oxadiazolin-2-one derivatives (6a-l), which on reaction with N2H4 gave the 4-amino-1,2,4-triazolin-3-ones (7a-l). All these compounds exhibited moderate antimicrobial activity against the few microbes tested. The carbamates have been found to be more toxic against fourth instar larvae of Aedes aegypti, in particular, the -butyl derivative (3e).

  18. Determination of Seven Carbamates Residues in Vegetable by HPLC%高效液相色谱法测定蔬菜中7种氨基甲酸酯类农药残留研究

    Institute of Scientific and Technical Information of China (English)

    王缇; 万妮


    [Objective] The aim was to establish an analysis method of carbamates residues. [ Method] The residues of aldiearb sulfone, alrli-carb sulfoxide, methomy), 3-hydroxy-carbofuran, aldiearb, carbofuran and carbryl in vegetable were determined by HPLC with fluorescence detector and post-column derivation, furthermore the fortified recoveries of seven carbamates in vegetable at 0.05, 0.10 and 0. 50 mg/kg were determined. [ Result] The recoveries of seven carbamates in vegetable ranged from 74.6% to 107. 6% , and the precision was less than 10%. [ Conclusion] The method is suitable for the determination of carbamates residues in Chinese cabbage, cucumber, tomato, pepper and celery.%[目的]建立一种氨基甲酸酯类农药残留分析方法.[方法]对市场上蔬菜随机抽样,采用配荧光检测器和柱后衍生系统的高效液相色谱议测定了蔬菜中涕灭威砜、涕灭威亚砜、灭多威、3-羟基克百威、涕灭威、克百威、甲萘威7种氨基甲酸酯类农药的多残留,对每种农药进行了3种不同浓度(0.05、0.10、0.50 mg/kg)的添加回收率试验.[结果]蔬菜中7种农药的回收率在74.6% ~ 107.6%,精密度在10%以内.[结论]该方法可用于大白菜、黄瓜、番茄、辣椒、芹菜等样品中氨基甲酸酯类农药残留分析.

  19. Molecular basis of neuroprotective activities of rasagiline and the anti-Alzheimer drug TV3326 [(N-propargyl-(3R)aminoindan-5-YL)-ethyl methyl carbamate]. (United States)

    Youdim, M B; Weinstock, M


    Rasagiline (N-propargyl-1-(R)-aminoindan) is a selective, irreversible monoamine oxidase B (MAO B) inhibitor which has been developed as an anti-Parkinson drug. In controlled monotherapy and as adjunct to L-dopa it has shown anti-Parkinson activity. In cell culture (PC-12 and neuroblastoma SH-SY5Y cells) it exhibits neuroprotective and anti-apoptotic activity against several neurotoxins (SIN-1, MPTP, 6-hydroxydopamine and N-methyl-(R)-salsolinol) and ischemia. In vivo, it reduces the sequelae of traumatic brain injury in mice and speeds their recovery. The neuroprotective activity of rasagaline does not result from MAO B inhibition, since its S-enantiomer, TVP1022, which has 1000-fold weaker MAO inhibitory activity, exhibits similar neuroprotective properties. Introduction of a carbamate moiety into the rasagiline molecule to confer cholinesterase inhibitory activity for the treatment of Alzheimer's disease, resulted in compounds TV3326 [(N-Propargyl-(3R)Aminoindan-5-YL)-Ethyl Methyl Carbamate] and its S-enantiomer TV3279 [(N-Propargyl-(3S)Aminoindan-5-YL)-Ethyl Methyl Carbamate], which retain the neuroprotective activities of rasagiline and TVP1022. They also antagonize scopolamine-induced impairments in spatial memory. In addition, TV3326 exhibits brain-selective MAO A and B inhibitory activity after chronic administration and has antidepressant-like activity in the forced swim test. This is associated with an increase in brain levels of serotonin. The anti-apoptotic activity of these propargylamine-containing derivatives may be related to their ability to delay the opening of voltage-dependent anion channels (VDAC), which are part of the mitochondrial permeability transition pore. The propargylamine moiety is responsible for the increase in the mitochondrial family of Bcl-2 proteins, prevention in the fall in mitochondrial membrane potential, prevention of the activation of caspase 3, and of translocation of glyceraldehyde-3-phosphate dehydrogenase from the

  20. A novel miniaturized zinc oxide/hydroxylated multiwalled carbon nanotubes as a stir-brush microextractor device for carbamate pesticides analysis

    Energy Technology Data Exchange (ETDEWEB)

    Makkliang, Fonthip; Kanatharana, Proespichaya [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Thavarungkul, Panote [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Physics, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Thammakhet, Chongdee, E-mail: [Trace Analysis and Biosensor Research Center, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand); Department of Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112 (Thailand)


    A novel miniaturized “stir-brush microextractor” was prepared using a zinc oxide/hydroxylated multiwalled carbon nanotubes (ZnO/MWCNTs–OH) coated stainless steel brush connected to a small dc motor. The synthesized zinc oxide on each strand of stainless steel had a flower-like nanostructure when observed by a scanning electron microscope (SEM). This structure produced a large surface area before it was coated with the hydroxylated multiwalled carbon nanotubes sorbent. Under optimal conditions, the developed device provided a good linearity for the extraction of carbofuran and carbaryl, in the range of 25–500 ng mL{sup −1} and 50–500 ng mL{sup −1}, respectively, with low limits of detection of 17.5 ± 2.0 ng mL{sup −1} and 13.0 ± 1.8 ng mL{sup −1}. It also provided a good stir-brush-to-stir-brush reproducibility (% relative standard deviation < 5.6%, n = 6). The device was applied for the extraction and preconcentration of carbamate pesticides in fruit and vegetable samples prior to analysis with a gas chromatograph coupled with a flame ionization detector (GC–FID). Carbofuran was found at 9.24 ± 0.93 ng g{sup −1} and carbaryl was detected at 7.05 ± 0.61 ng g{sup −1} with good recoveries in the range of 73.7 ± 10.0% to 108.4 ± 2.6% for carbofuran and 75.7 ± 10.0% to 111.7 ± 5.7% for carbaryl. - Highlights: • A brush as the sampling tool was first introduced. • A novel miniaturized and portable stir brush microextractor was developed for carbamate pesticides extraction. • Large surface area of ZnO flower-like nanostructure coated with MWCNTs–OH on each brush fiber was observed.

  1. Study of carbamate-modified disiloxane in porous PVDF-HFP membranes: new electrolytes/separators for lithium-ion batteries. (United States)

    Jeschke, Steffen; Mutke, Monika; Jiang, Zhongxiang; Alt, Burkhard; Wiemhöfer, Hans-Dieter


    A gel electrolyte membrane is obtained through the absorption of a carbamate-modified liquid disiloxane-containing lithium bis(trifluoromethane)sulfonimide (LiTFSI) by using macroporous poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) membranes. The porous membranes are prepared by means of a phase inversion technique. The resulting gel electrolyte membrane is studied by using differential scanning calorimetry, Fourier-transform infrared (FTIR) spectroscopy, and microscope mapping through coherent anti-Stokes Raman scattering (CARS) confocal microscopy and impedance spectroscopy. The ionic conductivity of the gel electrolyte is 10(-4) S cm(-1) at 20 °C. FTIR spectroscopy reveals interactions between LiTFSI and the carbonyl moiety of the disiloxane. No interactions between LiTFSI and PVDF-HFP or between disiloxane and PVDF-HFP are detected by FTIR spectroscopy. Furthermore, the distribution of the α and β/γ phases of PVDF-HFP and the homogeneous distribution of disiloxane/LiTFSI in the gel electrolyte membranes are examined by FTIR mapping. CARS confocal microscopy is used to image the three-dimensional interconnectivity, which reveals a reticulated structure of macrovoids in the porous PVDF-HFP framework. Owing to properties such as electrochemical and thermal stability of the disiloxane-based liquid electrolyte and the mechanical stability of the porous PVDF-HFP membrane, the gel electrolyte membranes presented herein are promising candidates for applications as electrolytes/separators in lithium-ion batteries.

  2. Antagonism at combined effects of chemical fertilizers and carbamate insecticides on the rice-field N2-fixing cyanobacterium Cylindrospermum sp. in vitro

    Directory of Open Access Journals (Sweden)

    Padhy Rabindra N.


    Full Text Available Effects of chemical fertilizers (urea, super phosphate and potash on toxicities of two carbamate insecticides, carbaryl and carbofuran, individually to the N2-fixing cyanobacterium, Cylindrospermum sp. were studied in vitro at partially lethal levels (below highest permissive concentrations of each insecticide. The average number of vegetative cells between two polar heterocysts was 16.3 in control cultures, while the mean value of filament length increased in the presence of chemical fertilizers, individually. Urea at the 10 ppm level was growth stimulatory and at the 50 ppm level it was growth inhibitory in control cultures, while at 100 ppm it was antagonistic, i.e. toxicity-enhancing along with carbaryl, individually to the cyanobacterium, antagonism was recorded. Urea at 50 ppm had toxicity reducing effect with carbaryl or carbofuran. At 100 and 250 ppm carbofuran levels, 50 ppm urea only had a progressive growth enhancing effect, which was marked well at 250 ppm carbofuran level, a situation of synergism. Super phosphate at the 10 ppm level only was growth promoting in control cultures, but it was antagonistic at its higher levels (50 and 100 ppm along with both insecticides, individually. Potash (100, 200, 300 and 400 ppm reduced toxicity due to carbaryl 20 and carbofuran 250 ppm levels, but potash was antagonistic at the other insecticide levels. The data clearly showed that the chemical fertilizers used were antagonistic with both the insecticides during toxicity to Cylindrospermum sp.

  3. Prediction of Multi-Target Networks of Neuroprotective Compounds with Entropy Indices and Synthesis, Assay, and Theoretical Study of New Asymmetric 1,2-Rasagiline Carbamates

    Directory of Open Access Journals (Sweden)

    Francisco J. Romero Durán


    Full Text Available In a multi-target complex network, the links (Lij represent the interactions between the drug (di and the target (tj, characterized by different experimental measures (Ki, Km, IC50, etc. obtained in pharmacological assays under diverse boundary conditions (cj. In this work, we handle Shannon entropy measures for developing a model encompassing a multi-target network of neuroprotective/neurotoxic compounds reported in the CHEMBL database. The model predicts correctly >8300 experimental outcomes with Accuracy, Specificity, and Sensitivity above 80%–90% on training and external validation series. Indeed, the model can calculate different outcomes for >30 experimental measures in >400 different experimental protocolsin relation with >150 molecular and cellular targets on 11 different organisms (including human. Hereafter, we reported by the first time the synthesis, characterization, and experimental assays of a new series of chiral 1,2-rasagiline carbamate derivatives not reported in previous works. The experimental tests included: (1 assay in absence of neurotoxic agents; (2 in the presence of glutamate; and (3 in the presence of H2O2. Lastly, we used the new Assessing Links with Moving Averages (ALMA-entropy model to predict possible outcomes for the new compounds in a high number of pharmacological tests not carried out experimentally.

  4. Utilization of charge-transfer complexation for the detection of carcinogenic substances in foods: Spectroscopic characterization of ethyl carbamate with some traditional π-acceptors (United States)

    Adam, Abdel Majid A.; Refat, Moamen S.; Saad, Hosam A.


    The study of toxic and carcinogenic substances in foods represents one of the most demanding areas in food safety, due to their repercussions for public health. One potentially toxic compound for humans is ethyl carbamate (EC). EC is a multi-site genotoxic carcinogen of widespread occurrence in fermented foods and alcoholic beverages. Structural and thermal stability of charge-transfer complexes formed between EC as a donor with quinol (QL), picric acid (PA), chloranilic acid (CLA), p-chloranil (p-CHL) and 1,3-dinitrobenzene (DNB) as acceptors were reported. Elemental analysis (CHN), electronic absorption spectra, photometric titration, IR, and 1H NMR spectra show that the interaction between EC and acceptors was stabilized by hydrogen bonding, via a 1:1 stoichiometry. Thermogravimetric (TG) analysis indicates that the formation of molecular CT complexes was stable, exothermic and spontaneous. Finally, the CT complexes were screened for their antibacterial and antifungal activities. The results indicated that the [(EC)(QL)] complex exhibited strong antimicrobial activities against various bacterial and fungal strains compared with standard drugs.

  5. Rapid and sensitive suspension array for multiplex detection of organophosphorus pesticides and carbamate pesticides based on silica-hydrogel hybrid microbeads. (United States)

    Wang, Xuan; Mu, Zhongde; Shangguan, Fengqi; Liu, Ran; Pu, Yuepu; Yin, Lihong


    A technique for multiplex detection of organophosphorus pesticides and carbamate pesticides has been developed using a suspension array based on silica-hydrogel hybrid microbeads (SHHMs). The main advantage of SHHMs, which consist of both silica and hydrogel materials, is that they not only could be distinguished by their characteristic reflection peak originating from the stop-band of the photonic crystal but also have low non-specific adsorption of proteins. Using fluorescent immunoassay, the LODs for fenitrothion, chlorpyrifos-methyl, fenthion, carbaryl and metolcarb were measured to be 0.02ng/mL, 0.012ng/mL, 0.04ng/mL, 0.05ng/mL and 0.1ng/mL, respectively, all of which are much lower than the maximum residue limits, as reported in the European Union pesticides database. All the determination coefficients for these five pesticides were greater than 0.99, demonstrating excellent correlations. The suspension array was specific and had no significant cross-reactivity with other chemicals. The results for the detection of pesticide residues collected from agricultural samples using this method agree well with those from liquid chromatography-tandem mass spectrometry. Our results showed that this simple method is suitable for simultaneous detection of these five pesticides residues in fruits and vegetables.

  6. Microwave accelerated selective Soxhlet extraction for the determination of organophosphorus and carbamate pesticides in ginseng with gas chromatography/mass spectrometry. (United States)

    Zhou, Ting; Xiao, Xiaohua; Li, Gongke


    Microwave accelerated selective Soxhlet extraction (MA-SSE), a novel selective extraction technique, was investigated in this study. A Soxhlet extraction system containing a glass filter was designed as an extractor. During the procedure of MA-SSE, both the target analytes and the interfering components were extracted from the sample into the extraction solvent enhanced by microwave irradiation. After the solvent flowed though the sorbent, the interfering components were adsorbed by the sorbent, and the target analytes remaining in the solvent were collected in the extraction bottle. No cleanup or filtration was required after extraction. The efficiency of the MA-SSE approach was demonstrated in the determination of organophosphorus and carbamate pesticide residues in ginseng by gas chromatography/mass spectrometry (GC/MS). Under the optimized conditions, low limits of detection (0.050-0.50 μg/kg) were obtained. The recoveries were in the range of 72.0-110.1% with relative standard deviations less than 7.1%. Because of the effect of microwave irradiation, MA-SSE showed significant advantage compared with other extraction techniques. The sorbent used in this study showed good cleanup ability. The mechanism of MA-SSE was demonstrated to be based on the rupture of the cell walls according to the structural changes of ginseng samples. On the basis of the results, MA-SSE as a simple and effective sample preparation technique for the analysis of pesticide residues in complex matrixes shows great promise.

  7. Constitutive expression of the DUR1,2 gene in an industrial yeast strain to minimize ethyl carbamate production during Chinese rice wine fermentation. (United States)

    Wu, Dianhui; Li, Xiaomin; Lu, Jian; Chen, Jian; Zhang, Liang; Xie, Guangfa


    Urea and ethanol are the main precursors of ethyl carbamate (EC) in Chinese rice wine. During fermentation, urea is generated from arginine by arginase in Saccharomyces cerevisiae, and subsequently cleaved by urea amidolyase or directly transported out of the cell into the fermentation liquor, where it reacts with ethanol to form EC. To reduce the amount of EC in Chinese rice wine, we metabolically engineered two yeast strains, N85(DUR1,2) and N85(DUR1,2)-c, from the wild-type Chinese rice wine yeast strain N85. Both new strains were capable of constitutively expressing DUR1,2 (encodes urea amidolyase) and thus enhancing urea degradation. The use of N85(DUR1,2) and N85(DUR1,2)-c reduced the concentration of EC in Chinese rice wine fermented on a small-scale by 49.1% and 55.3%, respectively, relative to fermentation with the parental strain. All of the engineered strains showed good genetic stability and minimized the production of urea during fermentation, with no exogenous genes introduced during genetic manipulation, and were therefore suitable for commercialization to increase the safety of Chinese rice wine.

  8. Resistência a inseticidas organofosforados e carbamatos em população de Culex quinquefasciatus Organophosphorous and carbamate resistence in a population of Culex quinquefasciatus

    Directory of Open Access Journals (Sweden)

    José Eduardo Bracco


    Full Text Available Relata-se a ocorrência, na população de Culex quinquefasciatus, de resistência a pelo menos dois organofosforados e a um carbamato (malathion, fenitrothion e propoxur, respectivamente, mostrando a necessidade de haver programa de manejo de inseticidas. A suscetibilidade dessa população ao piretróide permetrina indica essa classe como de escolha numa eventual necessidade de substituição dos organofosforados.The population of Culex quinquefasciatus breeding in the Pinheiros River (S. Paulo, Brazil has been controlled with organophosphates since 1980. However, the biting has constituted a continual nuisance to the human population who live in the vicinity of the river. The occurrence of insecticide resistance to at least two organophosphates and one carbamate (malathion, fenitrothion and propoxur, respectively to this insect population is reported. The results show the need to develop an insecticide management program. The suscetibility to permethrin (pyretroid suggests the possibility of using this class of insecticide shoul the need for replacement of the insecticide in use arise.

  9. [Effect of alcoholic strength on the determination of ethyl carbamate in Chinese spirits by high performance liquid chromatography-fluorescence detection]. (United States)

    Chen, Dawei; Miao, Hong; Zhao, Yunfeng; Wu, Yongning


    A high performance liquid chromatography-fluorescence detection (HPLC-FLD) method was established for rapid determination of ethyl carbamate (EC) in Chinese spirits. Through the analysis and comparison of the EC peak areas in different alcoholic strengths determined by HPLC-FLD, the effect of alcoholic strength on the determination of the content of EC was found. The alcoholic strength and the peak area of EC showed good linearity in the range of 5% to 65% (v/v) alcohol content, and the correlation coefficients (R2) were higher than 0.98. Furthermore, the conversion between the peak area of EC with different alcoholic strengths was established by the relative correction coefficient. The method showed a good linearity in the range of 10 to 500 microg/L for EC with the average recoveries of 98.9%-108.2% and RSDs of 0.6%-4.9%. The reliability of the established HPLC-FLD method was evaluated by comparison with GC-MS method. The results showed that the results of two methods were not significantly different. The developed method is simple, sensitive, accurate, and suitable for the rapid determination of EC in Chinese spirits.

  10. Determination of lead in blood by chelation with ammonium pyrrolidine dithio-carbamate followed by tungsten-coil atomic absorption spectrometry (United States)

    Salido, Arthur; Sanford, Caryn L.; Jones, Bradley T.


    An inexpensive, bench-top blood Pb analyzer has been developed. The system is based on tungsten-coil atomic absorption spectrometry. Pb atomization occurs on W-coils extracted from commercially available slide projector bulbs. The system has minimal power requirements: 120 ACV and 15 A. A small, computer-controlled CCD spectrometer is used as the detector. A Pb hollow cathode lamp is used as the source. Blood Pb is chelated with ammonium pyrrolidine dithio-carbamate and extracted into methyl iso-butyl ketone (4-methyl 2-pentanone). Twenty-microliter volumes of the organic phase are deposited on the W-coil, dried at 1.4 A, charred at 2.3 A and atomized at 6.0 A. Graphite furnace atomic absorption spectrometry is used as a comparison for W-coil results. Levels 1-4 of a NIST standard reference material 955b ‘lead in bovine blood’ are used to test accuracy and precision. The analytical figures of merit for the system are: 12-pg instrument detection limit, 24-pg blood detection limit and a characteristic mass of 28 pg.

  11. Measurement of (15)N enrichment of glutamine and urea cycle amino acids derivatized with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate using liquid chromatography-tandem quadrupole mass spectrometry. (United States)

    Nakamura, Hidehiro; Karakawa, Sachise; Watanabe, Akiko; Kawamata, Yasuko; Kuwahara, Tomomi; Shimbo, Kazutaka; Sakai, Ryosei


    6-Aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) is an amino acid-specific derivatizing reagent that has been used for sensitive amino acid quantification by liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS). In this study, we aimed to evaluate the ability of this method to measure the isotopic enrichment of amino acids and to determine the positional (15)N enrichment of urea cycle amino acids (i.e., arginine, ornithine, and citrulline) and glutamine. The distribution of the M and M+1 isotopomers of each natural AQC-amino acid was nearly identical to the theoretical distribution. The standard deviation of the (M+1)/M ratio for each amino acid in repeated measurements was approximately 0.1%, and the ratios were stable regardless of the injected amounts. Linearity in the measurements of (15)N enrichment was confirmed by measuring a series of (15)N-labeled arginine standards. The positional (15)N enrichment of urea cycle amino acids and glutamine was estimated from the isotopic distribution of unique fragment ions generated at different collision energies. This method was able to identify their positional (15)N enrichment in the plasma of rats fed (15)N-labeled glutamine. These results suggest the utility of LC-MS/MS detection of AQC-amino acids for the measurement of isotopic enrichment in (15)N-labeled amino acids and indicate that this method is useful for the study of nitrogen metabolism in living organisms.

  12. 酱油中氨基甲酸乙酯和氯丙醇含量调查与分析%Survey and analysis of ethyl carbamate and 3-chloro-1,2-propanediol (3-MCPD) in soy sauce

    Institute of Scientific and Technical Information of China (English)

    王立媛; 吴平谷; 张晶; 汤鋆; 赵永信


    Objective:To investigate the levels of 3 - chloro - 1,2 - propanediol(3 - MCPD) and ethyl carbamate in soy sauce. Methods: The total 135 soy sauce samples were collected from big, middle - sized and small supermarkets and farmer's market respectively. The 3 - chloro - 1,2 - propanediol(3 - MCPD) and ethyl carbamate were measured by gas chromatography - mass spectrometry in selection ion mode, after the samples were coupled with D5 - ethyl carbamate and D5 - 3 - chloro -1,2- propanediol ( 3 - MCPD ) , and purified by diatomite solid phase extraction coulum. Results: The results showed that ethyl carbamate was detected in all samples ( 100% ) with the range from 1. 6 μg/kg to 80. 8 μg/kg,the 3 - chloro - 1,2 - propanediol( 3 - MCPD) was detected in 32.05% of the samples with the range from 5. 8 μg/kg to 379. 10 μg/kg. Conclusion: In this investigation, the ethyl carbamate was detected in all soy sauce samples, and the level of 3 - chloro - 1,2 - propanediol(3 - MCPD) was not pretty low, and the data obtained in our test can be the references for risk assessment of ethyl carbamate and 3 - chloro - 1 ,2 - propanediol in soy sauce.%目的:调查本地市售酱油中氯丙醇和氨基甲酸乙酯含量.方法:在本市大、中、小超市及农贸市场采集135份酱油,采用d5-3-氯-1,2-丙二醇、D5-氨基甲酸乙酯同位素稀释技术,硅藻土固相萃取净化样品,然后用GC/MS测定样品中氯丙醇和氨基甲酸乙酯.结果:135份酱油中氨基甲酸乙酯检出率100%,含量范围为1.6 μg/kg~80.8 μg/kg;氯丙醇检出率为32.05%,含量范围为5.8 μg/kg~ 379.10 μg/kg.结论:本次调查显示酱油中均存在氨基甲酸乙酯,氯丙醇检出含量也不低,为开展酱油中氨基甲酸乙酯和氯丙醇的风险评估提供了基础数据.

  13. Rapid and sensitive suspension array for multiplex detection of organophosphorus pesticides and carbamate pesticides based on silica–hydrogel hybrid microbeads

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xuan [Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu (China); Mu, Zhongde; Shangguan, Fengqi [State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, Jiangsu (China); Liu, Ran; Pu, Yuepu [Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu (China); Yin, Lihong, E-mail: [Key Laboratory of Environmental Medicine Engineering, Ministry of Education, School of Public Health, Southeast University, Nanjing, Jiangsu (China)


    Highlights: • Silica–hydrogel hybrid microbeads were used to develop suspension array. • The results in detecting pesticides agree well with those from LC–MS/MS. • The method showed the good capability for multiplex analysis of pesticides residues. - Abstract: A technique for multiplex detection of organophosphorus pesticides and carbamate pesticides has been developed using a suspension array based on silica–hydrogel hybrid microbeads (SHHMs). The main advantage of SHHMs, which consist of both silica and hydrogel materials, is that they not only could be distinguished by their characteristic reflection peak originating from the stop-band of the photonic crystal but also have low non-specific adsorption of proteins. Using fluorescent immunoassay, the LODs for fenitrothion, chlorpyrifos-methyl, fenthion, carbaryl and metolcarb were measured to be 0.02 ng/mL, 0.012 ng/mL, 0.04 ng/mL, 0.05 ng/mL and 0.1 ng/mL, respectively, all of which are much lower than the maximum residue limits, as reported in the European Union pesticides database. All the determination coefficients for these five pesticides were greater than 0.99, demonstrating excellent correlations. The suspension array was specific and had no significant cross-reactivity with other chemicals. The results for the detection of pesticide residues collected from agricultural samples using this method agree well with those from liquid chromatography–tandem mass spectrometry. Our results showed that this simple method is suitable for simultaneous detection of these five pesticides residues in fruits and vegetables.

  14. Ethyl-bridged hybrid column as an efficient alternative for HPLC analysis of plasma amino acids by pre-column derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate. (United States)

    Castellanos, Mar; Van Eendenburg, Cecile Van; Gubern, Carme; Sanchez, Juan M


    Conventional C18 silica columns have proven to be useful for the analysis of amino acids (AA) from protein hydrolysates but undesirable peak overlapping is usually found when analyzing body fluids given that a large number of AAs are present in the samples. As an alternative to silica packings, an ethyl-bridged packing for reversed-phase liquid chromatography of derivatized AAs with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) has been evaluated. The new packing material improves the separation efficiency allowing better separations when analyzing biological fluids. Moreover, this packing has advantages for routine AA analysis, such as a decrease in the total running time and an increase in the life-time of the columns. The pH of the mobile phase has a significant effect on the elution behavior of the AQC hydrolysis product (AMQ) and on the AA derivatives. It is not possible to elute AMQ before detecting the first AA derivative, which requires an accurate adjustment of the pH in the range of 5.30-5.35 to obtain good separation and resolution for the most polar compounds. Under the conditions proposed, it is possible to separate all AAs except the Gly-Gln pair, which is not a problem when hydrolyzed samples are analyzed. The AMQ-Ser pair requires either the use of a different mobile phase pH for its baseline separation or the use of fluorescence detection. Two different procedures for protein removal from plasma samples have been evaluated, solvent precipitation and ultrafiltration (UF) and it has been found that UF gives better results as no significant losses of AAs were observed. The validation of the proposed method with UV detection gives method detection limits in the range of 8-12μM, with repeatability values<8% (n=6) and inter-day precision in plasma samples ranging from 4 to 13% (n=4).

  15. A novel miniaturized zinc oxide/hydroxylated multiwalled carbon nanotubes as a stir-brush microextractor device for carbamate pesticides analysis. (United States)

    Makkliang, Fonthip; Kanatharana, Proespichaya; Thavarungkul, Panote; Thammakhet, Chongdee


    A novel miniaturized "stir-brush microextractor" was prepared using a zinc oxide/hydroxylated multiwalled carbon nanotubes (ZnO/MWCNTs-OH) coated stainless steel brush connected to a small dc motor. The synthesized zinc oxide on each strand of stainless steel had a flower-like nanostructure when observed by a scanning electron microscope (SEM). This structure produced a large surface area before it was coated with the hydroxylated multiwalled carbon nanotubes sorbent. Under optimal conditions, the developed device provided a good linearity for the extraction of carbofuran and carbaryl, in the range of 25-500 ng mL(-1) and 50-500 ng mL(-1), respectively, with low limits of detection of 17.5 ± 2.0 ng mL(-1) and 13.0 ± 1.8 ng mL(-1). It also provided a good stir-brush-to-stir-brush reproducibility (% relative standard deviation < 5.6%, n = 6). The device was applied for the extraction and preconcentration of carbamate pesticides in fruit and vegetable samples prior to analysis with a gas chromatograph coupled with a flame ionization detector (GC-FID). Carbofuran was found at 9.24 ± 0.93 ng g(-1) and carbaryl was detected at 7.05 ± 0.61 ng g(-1) with good recoveries in the range of 73.7 ± 10.0% to 108.4 ± 2.6% for carbofuran and 75.7 ± 10.0% to 111.7 ± 5.7% for carbaryl.

  16. Determination of Neurotoxin b-ODAP and Non-protein Amino Acids in Lathyrus Sativus by High-Performance Liquid Chromatography with Precolumn Derivatization with 6-Amino quinolyl-N-hydroxysuccinimidyl Carbamate (AQC)

    Institute of Scientific and Technical Information of China (English)


    A new method was developed for the quantitative determination of the neurotoxic non-protein amino acid, 3-N-oxalyl-L-2,3-diaminopropionic acid (b -ODAP), its nontoxic a -isomer and other non-protein amino acids in the plant samples of Lathyrus sativus after derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) by reversed-phase high-performance liquid chromatography (HPLC). 2-Amino butyric acid (ABA) was used as an internal standard. The RP HPLC detection limit for both isomers is 1.8 ng with good response linearity. The results are compared with a colorimetric method.

  17. Ground-State Distortion in N-Acyl-tert-butyl-carbamates (Boc) and N-Acyl-tosylamides (Ts): Twisted Amides of Relevance to Amide N-C Cross-Coupling. (United States)

    Szostak, Roman; Shi, Shicheng; Meng, Guangrong; Lalancette, Roger; Szostak, Michal


    Amide N-C(O) bonds are generally unreactive in cross-coupling reactions employing low-valent transition metals due to nN → π*C═O resonance. Herein we demonstrate that N-acyl-tert-butyl-carbamates (Boc) and N-acyl-tosylamides (Ts), two classes of acyclic amides that have recently enabled the development of elusive amide bond N-C cross-coupling reactions with organometallic reagents, are intrinsically twisted around the N-C(O) axis. The data have important implications for the design of new amide cross-coupling reactions with the N-C(O) amide bond cleavage as a key step.

  18. The Repellent DEET Potentiates Carbamate Effects via Insect Muscarinic Receptor Interactions: An Alternative Strategy to Control Insect Vector-Borne Diseases.

    Directory of Open Access Journals (Sweden)

    Aly Abd-Ella

    Full Text Available Insect vector-borne diseases remain one of the principal causes of human mortality. In addition to conventional measures of insect control, repellents continue to be the mainstay for personal protection. Because of the increasing pyrethroid-resistant mosquito populations, alternative strategies to reconstitute pyrethroid repellency and knock-down effects have been proposed by mixing the repellent DEET (N,N-Diethyl-3-methylbenzamide with non-pyrethroid insecticide to better control resistant insect vector-borne diseases. By using electrophysiological, biochemichal, in vivo toxicological techniques together with calcium imaging, binding studies and in silico docking, we have shown that DEET, at low concentrations, interacts with high affinity with insect M1/M3 mAChR allosteric site potentiating agonist effects on mAChRs coupled to phospholipase C second messenger pathway. This increases the anticholinesterase activity of the carbamate propoxur through calcium-dependent regulation of acetylcholinesterase. At high concentrations, DEET interacts with low affinity on distinct M1/M3 mAChR site, counteracting the potentiation. Similar dose-dependent dual effects of DEET have also been observed at synaptic mAChR level. Additionally, binding and in silico docking studies performed on human M1 and M3 mAChR subtypes indicate that DEET only displays a low affinity antagonist profile on these M1/M3 mAChRs. These results reveal a selective high affinity positive allosteric site for DEET in insect mAChRs. Finally, bioassays conducted on Aedes aegypti confirm the synergistic interaction between DEET and propoxur observed in vitro, resulting in a higher mortality of mosquitoes. Our findings reveal an unusual allosterically potentiating action of the repellent DEET, which involves a selective site in insect. These results open exciting research areas in public health particularly in the control of the pyrethroid-resistant insect-vector borne diseases. Mixing low

  19. An UPLC-ESI-MS/MS Assay Using 6-Aminoquinolyl-N-Hydroxysuccinimidyl Carbamate Derivatization for Targeted Amino Acid Analysis: Application to Screening of Arabidopsis thaliana Mutants

    Directory of Open Access Journals (Sweden)

    Carolina Salazar


    Full Text Available In spite of the large arsenal of methodologies developed for amino acid assessment in complex matrices, their implementation in metabolomics studies involving wide-ranging mutant screening is hampered by their lack of high-throughput, sensitivity, reproducibility, and/or wide dynamic range. In response to the challenge of developing amino acid analysis methods that satisfy the criteria required for metabolomic studies, improved reverse-phase high-performance liquid chromatography-mass spectrometry (RPHPLC-MS methods have been recently reported for large-scale screening of metabolic phenotypes. However, these methods focus on the direct analysis of underivatized amino acids and, therefore, problems associated with insufficient retention and resolution are observed due to the hydrophilic nature of amino acids. It is well known that derivatization methods render amino acids more amenable for reverse phase chromatographic analysis by introducing highly-hydrophobic tags in their carboxylic acid or amino functional group. Therefore, an analytical platform that combines the 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC pre-column derivatization method with ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS is presented in this article. For numerous reasons typical amino acid derivatization methods would be inadequate for large scale metabolic projects. However, AQC derivatization is a simple, rapid and reproducible way of obtaining stable amino acid adducts amenable for UPLC-ESI-MS/MS and the applicability of the method for high-throughput metabolomic analysis in Arabidopsis thaliana is demonstrated in this study. Overall, the major advantages offered by this amino acid analysis method include high-throughput, enhanced sensitivity and selectivity; characteristics that showcase its utility for the rapid screening of the preselected plant metabolites without compromising the quality of the

  20. The Repellent DEET Potentiates Carbamate Effects via Insect Muscarinic Receptor Interactions: An Alternative Strategy to Control Insect Vector-Borne Diseases. (United States)

    Abd-Ella, Aly; Stankiewicz, Maria; Mikulska, Karolina; Nowak, Wieslaw; Pennetier, Cédric; Goulu, Mathilde; Fruchart-Gaillard, Carole; Licznar, Patricia; Apaire-Marchais, Véronique; List, Olivier; Corbel, Vincent; Servent, Denis; Lapied, Bruno


    Insect vector-borne diseases remain one of the principal causes of human mortality. In addition to conventional measures of insect control, repellents continue to be the mainstay for personal protection. Because of the increasing pyrethroid-resistant mosquito populations, alternative strategies to reconstitute pyrethroid repellency and knock-down effects have been proposed by mixing the repellent DEET (N,N-Diethyl-3-methylbenzamide) with non-pyrethroid insecticide to better control resistant insect vector-borne diseases. By using electrophysiological, biochemichal, in vivo toxicological techniques together with calcium imaging, binding studies and in silico docking, we have shown that DEET, at low concentrations, interacts with high affinity with insect M1/M3 mAChR allosteric site potentiating agonist effects on mAChRs coupled to phospholipase C second messenger pathway. This increases the anticholinesterase activity of the carbamate propoxur through calcium-dependent regulation of acetylcholinesterase. At high concentrations, DEET interacts with low affinity on distinct M1/M3 mAChR site, counteracting the potentiation. Similar dose-dependent dual effects of DEET have also been observed at synaptic mAChR level. Additionally, binding and in silico docking studies performed on human M1 and M3 mAChR subtypes indicate that DEET only displays a low affinity antagonist profile on these M1/M3 mAChRs. These results reveal a selective high affinity positive allosteric site for DEET in insect mAChRs. Finally, bioassays conducted on Aedes aegypti confirm the synergistic interaction between DEET and propoxur observed in vitro, resulting in a higher mortality of mosquitoes. Our findings reveal an unusual allosterically potentiating action of the repellent DEET, which involves a selective site in insect. These results open exciting research areas in public health particularly in the control of the pyrethroid-resistant insect-vector borne diseases. Mixing low doses of DEET and a

  1. Study on the Interaction between Humic Substances in Soil and Carbamate Pesticides Using Fluorescence Quenching Titration Method%荧光猝灭滴定法研究土壤腐殖质与氨基甲酸酯类农药相互作用

    Institute of Scientific and Technical Information of China (English)

    施国兰; 郑博福; 白英臣; 吴丰昌; 吴代赦


    为研究氨基甲酸酯类农药在溶解有机质参与下的迁移转化过程,利用荧光猝灭滴定法研究了土壤HS(腐殖质)与氨基甲酸酯类农药的相互作用.结果表明,呋喃丹和西维因的荧光都能不同程度地被FA(富里酸)和HA(腐殖酸)猝灭,主要猝灭机理为静电结合猝灭.采用静态猝灭模型计算出氨基甲酸酯类农药与HS的K(结合常数),lg K由大到小为呋喃丹-HA(4.96)>西维因-HA(4.93)>呋喃丹-FA(4.72)>西维因-FA(4.68).HA与氨基甲酸酯类农药的lgK明显大于FA与氨基甲酸酯类农药,表明HS与氨基甲酸酯类农药间的作用力有疏水作用.进一步研究表明,氢键作用对HS与氨基甲酯类农药结合有一定的影响.%To reveal the mechanisms of transport and conversion of carbamate pesticides in the presence of dissolved organic matters, the fluorescence quenching titration method was applied to investigate the interactions between carbamate pesticides and humic substances in soil. The results showed that the intrinsic fluorescence of carbofuran and carbaryl was quenched by the fulvic and humic acids to varying degrees. Static quenching was the primary mechanism during this process. The binding constants (K) of carbamate pesticides and humic substances were estimated using the fluorescence static quenching model. The order of lg K were: those of carbofuran and humic acid (4. 96) > those of carbaryl and humic acid (4. 93) > those of carbofuran and fulvic acid (4. 72) > those of carbaryl and fulvic acid (4. 68). The values of lg K of carbamate pesticides and humic acids were clearly higher than those of carbamate pesticides and fulvic acids. This result indicated that the hydrophobic force is one of the main interactions between carbamate pesticides and humic substances, and further proved that hydrogen bonding could slightly affect the bonding of carbamate pesticides and humic substances.

  2. Selection of Extraction Column in Solid Phase Extraction of Ethyl Carbamate%固相萃取氨基甲酸乙酯过程萃取柱的选择比较

    Institute of Scientific and Technical Information of China (English)

    严敏; 吕昱; 黄云芳


    In this study, the extracting effects of each extraction column in the extraction of ethyl carbamate were investigated to obtain the opti-mum extracting conditions and the best extraction column. Meanwhile, the selection method of the extraction column in solid phase EC extrac-tion technique was established and further optimized. Firstly, 5 mL ethyl carbamate was taken, pH value adjusted to 7.5, balancing time was 10 mins, the extracting time was 30 mins, then sample desorption by gas-phase held for 10 mins, then several kinds of extraction columns includ-ing silica gel column, Welchrom Florisil, Welchrom Silica, Aglient Technologies and Welchrom C18 were selected for comparative study. The re-sults suggested that, Welchrom C18 had the best decolorization and impurity-removal effects with more stable baseline and easier quantitative analysis and the highest recovery rate. Finally, Welchrom C18 was selected for sample purification. The study provided foundation for further re-search on ethyl carbamate solid-phase extraction.%以固相萃取前处理技术作为重点研究对象,在固相萃取氨基甲酸乙酯的技术中,检测出各萃取柱的萃取效果,找到最佳的萃取条件和萃取柱,优化建立固相萃取EC萃取柱技术的选择比较的方法。取5 mL的氨基甲酸乙酯,调节pH7.5,平衡时间10 min,萃取时间30 min,气相进样解吸10 min。选用硅胶柱Welchrom Florisil、Wel-chrom Silica、Aglient Technologies和Welchrom C18进行对比研究。结果表明,Welchrom C18脱色除杂效果最好且基线较为平稳,更易定量,回收率最高;最后选择Welchrom C18用于样品净化。研究为固相萃取氨基甲酸乙酯技术中的进一步研究提供前期的基础。

  3. Structure and Vibrational Spectra of Tert-butyl N-(2- bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate%Tert-butyl(N-(2-bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate的结构和振动光谱

    Institute of Scientific and Technical Information of China (English)


    The molecular structure, conformational stability, and vibrational frequencies of tert-butyl N-(2-bromocyclohex-2-enyl)-N-(2-furylmethyl)carbamate (TBBFC) were investigated by utilizing the Hartree-Fock (HF) and density functional theory (DFT) ab initio calculations with 6-31G* and 6-31G* * basis sets. The optimized bond length and angle values obtained by HF method showed the best agreement with the experimental values. Comparison of the observed and calculated fundamental vibrational frequencies indicated that B3LYP was superior to the scaled HF approach for molecular problems. Optimal uniform scaling factors calculated for the title compound are 0.899/0.904,0.958/0.961, and 0.988/0.989 for HF, B3LYP, and BLYP (6-31G */6-31G* *), respectively.

  4. Validation and use of a fast sample preparation method and liquid chromatography-tandem mass spectrometry in analysis of ultra-trace levels of 98 organophosphorus pesticide and carbamate residues in a total diet study involving diversified food types. (United States)

    Chung, Stephen W C; Chan, Benny T P


    This paper reports a comprehensive sensitive multi-residue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for detection, identification and quantitation of 73 pesticides and their related products, a total of 98 analytes, belonging to organophosphorus pesticides (OPPs) and carbamates, in foods. The proposed method makes use of a modified QuEChERS (quick, easy, cheap, effective, rigged, and safe) procedure that combines isolation of the pesticides and sample clean-up in a single step. Analysis is performed by liquid chromatography-electrospray ionization-tandem mass spectrometry operated in the multiple reaction monitoring (MRM) mode, acquiring two specific precursor-product ion transitions per target compound. Two main fragment ions for each pesticide were obtained to achieve the identification according to the SANCO guidelines 10684/2009. The method was validated with various food samples, including edible oil, meat, egg, cheese, chocolate, coffee, rice, tree nuts, citric fruits, vegetables, etc. No significant matrix effect was observed for tested pesticides, therefore, matrix-matched calibration was not necessary. Calibration curves were linear and covered from 1 to 20 microg L(-1) for all compounds studied. The average recoveries, measured at 10 microg kg(-1), were in the range 70-120% for all of the compounds tested with relative standard deviations below 20%, while a value of 10 microg kg(-1) has been established as the method limit of quantitation (MLOQ) for all target analytes. Similar trueness and precision results were also obtained for spiking at 200 microg kg(-1). Expanded uncertainty values were in the range 21-27% while the HorRat ratios were below 1. The method has been successfully applied to the analysis of 700 food samples in the course of a baseline monitoring study of OPPs and carbamates.

  5. Novel PdCI 2 (RuCI 3)/ZrO2SO3 Catalysts for Synthesis of Carbamates by Oxidative Carbonylation of Amines%一种胺氧化羰化制氨基甲酸酯新催化剂体系

    Institute of Scientific and Technical Information of China (English)

    石峰; 司马天龙; 邓友全


    Novel combined PdC12 (RuCl3) with ZrO2-SO3 catalysts were developed for the synthesis of carbamates by oxidative carbonylation of aliphatic and aromatic amines. At 170 ℃ and 4.0 MPa, oxidative carbonylation of aromatic amines to the corresponding carbamates over this catalyst system could be proceeded with a high conversion and selectivity. Especially when β-naphthylamine was used as the substrate, 100% conversion and 95% selectivity were obtained in only 15 min. The catalytic performance of PdCl2/ZrO2-SO3 was better than that of RuCl3/ZrO2-SO3 for such oxidative carbonylation reaction.Possible role of ZrO2-SO3 as co-catalyst was also conjectured.

  6. 烟台市发酵性调料中氨基甲酸乙酯污染状况调查%Detection of ethyl carbamate in fermented condiments in Yantai city

    Institute of Scientific and Technical Information of China (English)

    付竹霓; 王璇; 王鹏; 孙成铭; 初永丽; 李杰


    目的:探讨烟台市发酵调料中氨基甲酸乙酯(ethyl carbamate,EC)污染状况,对本地区发酵性调料的食品安全性进行调查与评估.方法:随机选取2011年烟台市超市及食品供销部的158份发酵食品,应用基质固相分散萃取(MSPD)技术GC/MS定量分析各类发酵调料食品中EC的含量.结果:(1)158份发酵性调料食品中阳性样品数为117份,阳性率为74.05%,其中黄酒及料酒中EC阳性率最高,平均含量分别为73.1 μg/kg、66.4tμg/kg,酱油和食醋中EC的含量相对较低,平均含量为40.3 μg/kg、29.1μg/kg,腐乳EC平均含量为27.5 μg/kg;(2)EC阳性腐乳样品数为36份,其中红腐乳19份,白腐乳17份,两组间EC含量水平无显著差异性.结论:烟台市发酵调料食品中普遍存在EC,其中黄酒及料酒中EC阳性率最高,且EC含量最高值为100.2 mg/L,发酵调料的食品安全问题应进一步加强监管、严格调控.%Objective:To investigate ethyl carbamate (EC) concentrations in fermented condiments in Yantai in 2011, and to estimate the food safety of fermented condiments in the region. Methods: 158 fermented condiment samples of five categories were randomly selected from super markets and local shops of Yantai. The EC levels in the fermented condiment samples were detected by using the matrix solid phase dispersion extraction method for GC - MS analysis. Results: 1- There were 117 EC positive samples among the 158 fermented seasonings, the positive rate was 74. 05%. The positive rates of EC in yellow wine and cooking wine were the highest, and their averages were 73. 1 μg/kg and 66.4 μg/kg respectively. The concentrations of EC in soy sauce and vinegar were relatively lower, and the averages were 40. 3 μg/kg and 29. 1 μg/kg respectively. The average concentration of EC in fermented bean curd was 27. 5 μg/kg. 2. There were 36 EC positive samples among the 40 fermented bean curd samples, including 19 EC positive samples of red bean curd and 17 EC

  7. GC-MS法高灵敏检测蔬菜中氨基甲酸酯农药残留%Detection of pesticides residues of carbamate in vegetables by GC-MS

    Institute of Scientific and Technical Information of China (English)

    王俊; 管有志; 于微; 谭洪兴; 朱李佳; 刘小立


    目的 建立使用气质联用法同时检测蔬菜中多种氨基甲酸酯快速灵敏的检测方法.方法 样品经乙腈提取,固相萃取柱净化,并建立一种快速测定蔬菜中6种氨基甲酸酯类农药残留(异丙威、仲丁威、残杀威、抗芽威、速灭威、甲奈威)的气相色谱质谱联用(GC-MS)检测方法.同时对22种蔬菜中的多种氨基甲酸酯类农药进行定性及定量分析. 结果 建立一种快速测定蔬菜中6种氨基甲酸酯类农药残留的GC-MS方法,该方法对6种氨基甲酸酯类农药的相对标准偏差为1.06%~3.73%,回收率为86.5%~112.3%,并具有较好的精密度.在应用该方法检测的22种蔬菜中,一份空心菜检测出残杀威,一份香菜中检测出异丙威. 结论 本文建立的快速测定蔬菜中6中氨基甲酸酯类农药的GC-MS方法准确可靠,灵敏度高,可应用于蔬菜中多种氨基甲酸酯农药的同时测定.%Objective To set up a reliable method for determination of six carbamates in vegetables by using GC-MS.. Methods Samples were extracted with acetonitrile and then purified by solid-phase extraction (SPE). A method on rapid detection of six carbamates (Isoprocarb,BPMC,Propoxur,Pirimicarb,MTMC,Carbaryl)in samples by GC-MS has been established. Qualitative and quantitative analysis of pesticide residues in 22 vegetables from local supermarket have been performed by the proposed method. Results The relative standard deviations of the method were between 1.06% and 3.73%,and the method recoveries were in the range of 86.5-112.3% with good precision. Propoxur in water spinach and Isoprocarb in caraway have positive test results in our experiments. Conclusions The method was highly sensitive with satisfied recovery and it could be applied to detect six carbamates residues in vegetables quickly and accurately.

  8. Cancer risk assessment of ethyl carbamate in yellow rice wine%黄酒中氨基甲酸乙酯癌症风险评估研究进展

    Institute of Scientific and Technical Information of China (English)

    方益荣; 叶冬青


    氨基甲酸乙酯(Ethyl carbamate,EC)被认为是一种致癌物质,广泛存在于发酵食品和饮料中.2007年,国际癌症研究机构将其升级为2A类致癌物,即可能对人类致癌.黄酒中的EC含量较高,从5.0μg/L到482.6μg/L不等.欧洲食品安全委员会已经推荐使用暴露边界比(Margin of Exposure,MOE)来进行酒精饮料中EC的风险评估,MOE越小,则风险越大.目前认为MOE值为10000是公共卫生风险的阈值,如MOE值小于3800,则需考虑采取干预措施.但这种风险评估方法至少有2种不足,一是结论是由动物实验的结果推延至人类,二是这种定量评估方法不能分清乙醇和EC的作用,也不能分析EC与乙醛,以及其他致癌物的交互作用.

  9. 中国媒介蚊虫对有机氯类和氨基甲酸酯类杀虫剂的抗性调查%Investigation on the resistance of vector mosquitoes to organochlorines and carbamates in China

    Institute of Scientific and Technical Information of China (English)

    刘斯璐; 崔峰; 燕帅国; 乔传令


    Mosquitoes, due to their special behaviors, physiological characteristics and close relationship with human life,have been important vectors of some human diseases.The resistance of mosquitoes to insecticides is considered to be an evolutionary adaptation to environmental changes in response to applications of chemical insecticides.In this review we summarize the findings from the investigations implimented since 1990s on the resistance of the seven mosquito species in China (Culex pipiens complex, Anopheles sinesis, Ex.tritaeniorhynchus, An.minimus, An.lesteri, Aedes albopictus and Aedes aegypti) to organochlorines and carbamates.It is found that there are 7 species of vector mosquitoes that have a high level of resistance to DDT.So far only the resistance of Cx.pipiens to BHC and acetophenate has been documented and a low resistance of the vector to the insectisides reported.Investigations on the resistance of the insects to carbamates have been conducted mainly through evaluating the resistance of Cx.pipiens complex to suncide and bassa, with a low resistance found.%蚊虫由于其特殊的行为、生理以及与人类生活关系紧密而成为传播人类疾病的重要媒介,自20世纪化学杀虫剂广泛使用后,蚊虫就与这种环境变化协同进化,即通过生理生化多种机制产生抗药性.该文综述了自20世纪90年代以来,我国7种媒介蚊虫(尖音库蚊复组、中华按蚊、三带喙库蚊、微小按蚊、雷氏按蚊、白纹伊蚊和埃及伊蚊)对有机氯类和氨基甲酸酯类杀虫剂的抗性调查结果.结果 显示,不同地区的7种媒介蚊虫对DDT抗性水平较高,对六六六、三氯杀虫酯抗性调查较少,仅有库蚊对这2种杀虫剂抗性调查的报道,并且抗性水平较低.对氨基甲酸酯类杀虫剂的抗性调查,主要是尖音库蚊复组对残杀威和巴沙的抗性调查报道,抗性水平较低.

  10. Survey and analysis of fermented food contamination with ethyl carbamate%发酵食品中氨基甲酸乙酯污染状况调查与分析

    Institute of Scientific and Technical Information of China (English)

    龙顺荣; 周勇; 郦明浩; 谭锦萍; 杨晓云


    Survey and analysis of fermented food contamination with ethyl carbamate ( EC ) were carried out using GC/MS/MS with liquid-liquid extraction and matrix solid phase dispersion extraction as pretreatment method.There were 343 EC positive samples among the 437 fermented foods, and the positive rate was 78.49% .The results showed that fruit wine had highest positive rate of 100% , and the positive rates of soy sauce, vinegar and yellow wine were inferior to fruit wine with 98.17% , 86.67% and 78.83% , respectively.The lowest positive rate of beer was not detected.The wine with the highest averages of EC was yellow wine with 90.4 μg/L, followed by health care wine with 62.9 μg/L.The wine with the lowest average was wine with 7.6 μg/L.The average contents of condiments in soy sauce and vinegar were 84.1 μg/kg and 76.2 μg/kg, respectively.The average content of baking foods in bread was 24.3 μg/kg.The results showed that the yellow wine, soy sauce and vinegar had relatively higher average content and positive rate, therefore fermented food contamination must be emphasized in further research and supervision.%采用液液萃取和基质固相分散的样品前处理技术,应用气相色谱-串联质谱的检测方法对发酵食品中氨基甲酸乙酯(ethyl carbamate,EC)的污染状况进行调查和分析,共检测发酵食品437批次,其中EC阳性样品343批次,阳性率为78.49%,阳性率最高的是果酒100%,其次是酱油98.17%、醋86.67%和黄酒78.38%,最低的是啤酒,为未检出.饮料酒中EC平均值最高的是黄酒90.4 μg/L,其次为保健酒62.9 μg/L,最低为葡萄酒,为7.6 μg/L,调味品中酱油和醋EC平均值分别为84.1 μg/kg和76.2 μg/kg,焙烤食品中面包EC平均值24.3μg/kg.研究结果表明,黄酒、酱油和醋中EC的阳性率、平均值相对较高,在今后的研究和监测中需要重点关注.

  11. Effets de l'exposition à un insecticide carbamate, le carbofuran, sur les performances de jeunes stades de brochet (Esox lucius L., 1758 : résultats préliminaires

    Directory of Open Access Journals (Sweden)



    Full Text Available Des lots de jeunes brochets au stade embryon libre, stabulés dans des béchers en verre, ont été exposés en conditions statiques à des solutions (0-250 µg.L-1 de carbofuran, un insecticide carbamate inhibiteur de l'activité de l'acétylcholinestérase (AchE. A partir de 10 µg.L-1, une inhibition significative de l'activité globale de l'AchE des embryons libres a été constatée. A partir de 50 µg.L-1, une diminution significative de la hauteur moyenne de fixation des embryons libres sur les parois des béchers a été observée. L'exposition au carbofuran n'a pas eu d'effet significatif sur le nombre de proies zooplanctoniques ingérées par les jeunes brochets parvenus au début de la phase larvaire ; une diminution de ce paramètre en fonction de concentrations croissantes de carbofuran a cependant été enregistrée. A 250 µg.L-1 , la résorption de la vésicule vitelline ne s'effectuant plus que très partiellement, les embryons libres exposés ne se sont pas transformés en larves. Cette étude montre que l'exposition à des concentrations sublétales de carbofuran est susceptible d'affecter le développement ontogénétique et les performances de jeunes stades de brochet. Un approfondissement de ces travaux est envisagé dans différentes directions.

  12. Impairment of the ubiquitin-proteasome pathway by methyl N-(6-phenylsulfanyl-1H-benzimidazol-2-yl)carbamate leads to a potent cytotoxic effect in tumor cells: a novel antiproliferative agent with a potential therapeutic implication. (United States)

    Dogra, Nilambra; Mukhopadhyay, Tapas


    In recent years, there has been a great deal of interest in proteasome inhibitors as a novel class of anticancer drugs. We report that fenbendazole (FZ) (methyl N-(6-phenylsulfanyl-1H-benzimidazol-2-yl)carbamate) exhibits a potent growth-inhibitory activity against cancer cell lines but not normal cells. We show here, using fluorogenic substrates, that FZ treatment leads to the inhibition of proteasomal activity in the cells. Succinyl-Leu-Leu-Val-Tyr-methylcoumarinamide (MCA), benzyloxycarbonyl-Leu-Leu-Glu-7-amido-4-MCA, and t-butoxycarbonyl-Gln-Ala-Arg-7-amido-4-MCA fluorescent derivatives were used to assess chymotrypsin-like, post-glutamyl peptidyl-hydrolyzing, and trypsin-like protease activities, respectively. Non-small cell lung cancer cells transiently transfected with an expression plasmid encoding pd1EGFP and treated with FZ showed an accumulation of the green fluorescent protein in the cells due to an increase in its half-life. A number of apoptosis regulatory proteins that are normally degraded by the ubiquitin-proteasome pathway like cyclins, p53, and IκBα were found to be accumulated in FZ-treated cells. In addition, FZ induced distinct ER stress-associated genes like GRP78, GADD153, ATF3, IRE1α, and NOXA in these cells. Thus, treatment of human NSCLC cells with fenbendazole induced endoplasmic reticulum stress, reactive oxygen species production, decreased mitochondrial membrane potential, and cytochrome c release that eventually led to cancer cell death. This is the first report to demonstrate the inhibition of proteasome function and induction of endoplasmic reticulum stress/reactive oxygen species-dependent apoptosis in human lung cancer cell lines by fenbendazole, which may represent a new class of anticancer agents showing selective toxicity against cancer cells.

  13. Rat dried blood spot analysis of (R,S)-(-)- and (S,R)-(+)- enantiomers of emtricitabin on immobilized tris-(3,5-dimethylphenyl carbamate) amylose silica as a chiral stationary phase. (United States)

    Rao, Ramisetti Nageswara; Santhakumar, Kondapalli; Naidu, Challa Gangu


    An enantioselective high performance liquid chromatography method has been developed and validated by evaluating the suitability of newly introduced immobilized polysaccharide chiral stationary phases, the effect of different organic modifiers and temperature including the entropy and enthalpy on resolution of the (R,S)-(-) & (S,R)-(+) emtricitabine enantiomers on rat dried blood spots. Both the enantiomers were extracted from dried blood spots using ethanol: methanol (80:20 v/v) mixture and separated on an immobilized amylose tris-(3,5-dimethyl phenyl carbamate) chiral stationary phase using n-hexane:ethanol (65:35 v/v) as a mobile phase at a flow rate of 0.8mL/min. The detection was carried out at 280nm using photo diode array detector connected to a polarimeter in series to determine their order of eluton. The method was validated with respect to limits of detection and quantification, linearity, accuracy and precision. The calibration curves were linear over the concentration range of 0.5-500μg/mL for both enantiomers and the correlation coefficient (r(2)) was >0.998. The overall recovery of (R,S)- & (S,R)-enantiomers of emtricitabin from DBS were 90.4 and 90.6%, respectively. The limits of detection and quantification of enantiomers were 0.26, 0.30 and 0.85, 0.92μg/mL for (R,S)- and (S,R)-emtricitabin enantiomers, respectively. The assay was specific and precise (RSD <10%). The stability of emtricitabin was also performed and the results were found to be well within the limits. The effect of hematocrit on extraction of emtricitabin enantiomers from dried blood spots was evaluated and no interference from endogenous substances was observed.

  14. 磷酸-氨基甲酸酯化变性淀粉对粘胶纱低温上浆性能的影响%Effects of phosphate-carbamate starch on the sizing properties of viscose yarns at low temperature

    Institute of Scientific and Technical Information of China (English)



    测试了磷酸-氨基甲酸酯化变性淀粉的透明度、粘度、粘度热稳定性以及对粘胶纱的粘附性能,研究了该淀粉在热敏感型粘胶纱低温上浆中应用的可行性.结果表明:淀粉经复合酯化变性后能改善淀粉糊的透明度,提高淀粉浆液的抗凝胶性能,浆液在60~80℃时仍具有良好的粘度稳定性;能显著提高对粘胶纱的粘附性能,浆液温度的降低对粘附力没有明显影响,能够用于粘胶经纱低温上浆.%The transparency, viscosity, viscosity thermal stability of the phosphate-carbamate starch and the adhesion to viscose fiber were measured. The feasibility of application of starch in sizing heat-sensitive viscose yarns at low temperature was discussed. The results showed that the modification was favorable to improve the transparency and anti-gelling behavior of the starch paste. Phosphate-carbamate starch paste could also keep good viscosity stability at 60~80 ℃. The adhesion of phosphate-carbamate starch for viscose fiber could be significantly improved and the reduction of the temperature of size liquid had little effect on the adhesion. The modified starch could meet the requirements for sizing viscose yarns under lower temperature.

  15. 杭州市市供豇豆有机磷类和氨基甲酸酯类农药残留监测结果分析%The monitoring results of organophosphate and carbamate pesticide residues in cowpea in Hangzhou

    Institute of Scientific and Technical Information of China (English)

    金旭忠; 徐庭巧; 何良兴


    目的:分析杭州市市供豇豆农药残留情况,为蔬菜质量安全的监管提供科学依据.方法:采集豇豆样品750批次,测定19种有机磷类农药残留量和10种氨基甲酸酯类农药残留量.结果:26批次样品为阳性,超标率为3.47%,其中,3批次样品有机磷类农药超标,超标率为0.40%,23批次样品氨基甲酸酯类农药残留超标,超标率为3.07%.结论:豇豆中农药超标较为严重,检出农药中涉及克百威、氧化乐果、水胺硫磷等禁用农药,需进一步加强监管.%Objective:To investigate the conditions of organophosphate and carbamate pesticide residues in cow-pea in Hangzhou in order to provide the basis for surveillance and control of vegetables safety. Methods: The total 750 samples of cowpea were collected and organophosphorus residues and carbamate pesticide residues in these samples were measured. Results: The disqualification rate of cowpea was 3.47 %. The disqualification rate of organophosphate and carbamate pesticide residues in cowpea were 0.40% , 3.07% respectively. Conclusion:The situation of pesticide residues in cowpea was relatively severe. Some forbidden pesticides were found. So the supervision and administration on the forbidden pesticides should be strengthened.

  16. Detection of 20 carbamate pesticides in asparagus by ultra performance liquid chromatography-electrospray ionization-mass spectrometry-mass spectrometry%超高效液相色谱-电喷雾串联四极杆质谱法检测芦笋中20种氨基甲酸酯类农药残留

    Institute of Scientific and Technical Information of China (English)

    赵晓琳; 霍乃蕊; 花锦; 宋欢


    目的:建立芦笋及其罐头制品中20种氨基甲酸酯类农药残留的定性定量分析方法。方法采用改进的 QuEchERS 法提取和净化,利用超高效液相色谱-电喷雾串联四极杆质谱仪,在多反应监测正离子扫描模式下对样品进行添加回收率试验。结果分别对绿芦笋、白芦笋、绿芦笋罐头、白芦笋罐头4种空白基质添加0.005~0.050 mg/kg农药样品进行回收率试验,回收率为62.44%~85.99%,定量限均为0.005 mg/kg, RSD均小于9%。结论该方法简单快速,灵敏度高,能够同时满足芦笋及其罐头制品中20种氨基甲酸酯类农药残留的检测要求。%Objective To establish an ultra performance liquid chromatography-electrospray ionization-mass spectrometry-mass spectrometry method for detecting of 20 kinds of carbamate pesticides in asparagus and asparagus products. Methods Samples were extracted by modified QuEchERS method, and the mode of multi-reaction monitoring positive ion scanning was applied for analysis by ultra high performance liquid chromatography-electrospray tandem quadrupole mass spectrometer. Results The blank matrixes (green asparagus, white asparagus, canned white asparagus, canned white asparagus) were added 0.005~0.050 mg/kg carbamate pesticides separately and recovery tests were performed. Results demonstrated that the recovery rates were in the range of 62.44%~85.99% and the limits of quantification were 0.005 mg/kg for all the 20 carbamate pesticides tested with the relative standard deviations (RSDs) below 9%. Conclusion The method, not only simple and fast but also high sensitive, can satisfy the international detection requirement for 20 carbamate pesticides residue in asparagus product simultaneously.

  17. 固相膜萃取-高效液相色谱法测定饮用水中12种氨基甲酸酯类农药残留%Determination of twelve carbamate residues in drinking water by HPLC after solid-phase membrane extraction

    Institute of Scientific and Technical Information of China (English)

    杨晓松; 余辉菊; 马子元


    目的:建立固相膜萃取-高效液相色谱法测定饮用水中灭多威、涕灭威、速灭威、残灭威、呋喃丹、甲萘威、抗杀虫威、异丙威、硫双威、仲丁威、猛杀威、杀虫威等12种氨基甲酸酯类农药残留量的方法.方法:水样经C18固相萃取膜真空抽滤,滤膜用乙酸乙酯洗脱,洗脱液经氮吹、甲醇溶解,高效液相色谱法测定.结果:12种氨基甲酸酯类农药的线性范围为0.05 mg/L~25.0 mg/L,线性相关系数大于0.999,检出限为0.31 mg/L~1.25 mg/L,水样中氨基甲酸酯类农残最低检测浓度范围为0.005 mg/L~0.019 mg/L,加标回收率为59.3%~97.3%,RSD<7.5%.结论:本方法样品前处理方便、快捷,有机试剂用量少.%Objective:To establish a method for determination of 12 carbamate residues including methomyl, al-dicarb, metolcarb, profluoralin, furadan, methyl carbamate, pirimicarb, isoprocarb, thiodicarb, fenobucarb, promecarb and tetrachlorvinphose in drinking - water by high performance liquid chromatography after solid - phase membrane extraction. Methods: The water sample was filtered through the conditioned solid - phase membrane under vacuum. The carbamales absorbed on the membrane were eluted using ethyl acetate and the eluted solution was blown to dryness under nitrogen gas. The residue was reconstituted with methanol and analyzed by HPLC. Results: The linear range of 12 carbamates residues were between 0. 05 mg/L to 25. 0 mg/L with r >0. 999. The detection limits were 0. 31 mg/L to 1.25 mg/L. The lowest detection limits of carbamate residues in the sample water were between 0.005 mg/L and 0.019 mg/L. The recoveries ranged from 59. 3% to 97. 3% with RSD <7.5% . Conclusion: The method can be used for the multi -residue analysis of carbamate residues in drinking water.

  18. Organofosforados e carbamatos no leite produzido em quatro regiões leiteiras no Brasil: ocorrência e ação sobre Listeria monocytogenes e Salmonella spp. Organophosphates and carbamates in milk produced in four milk producing regions from Brazil: occurrence and activity against Listeria monocytogenes and Salmonella spp.

    Directory of Open Access Journals (Sweden)

    Luís Augusto Nero


    Full Text Available Organofosforados e carbamatos são compostos utilizados no controle de parasitas em animais e podem gerar resíduos nos produtos alimentícios derivados, representando um risco para o consumidor. O presente estudo objetivou pesquisar a presença de resíduos de organofosforados e carbamatos em leite cru produzido em quatro regiões leiteiras no Brasil e verificar se a presença desses compostos teria alguma relação com a ausência de Listeria monocytogenes e Salmonella spp., anteriormente observada nessas amostras. Entre 209 amostras analisadas, a presença de ao menos um desses compostos foi detectada em 196 (93,8%. Para a avaliação da sua interferência na detecção de L. monocytogenes e Salmonella spp., 28 amostras de leite positivas e negativas para esses compostos foram submetidas à fervura por 10 minutos e adicionadas desses patógenos, monitorando-se sua multiplicação durante armazenamento a 4 °C e a 25 °C. Não houve diferença significativa (p Chemical residues may be present in foods due to contamination in early stages of production, posing a potential risk to consumers. Organophosphates and carbamates are used in the control of parasites in animals and may generate residues in foods derived from these animals, like milk. This study aimed to survey the presence of these two pesticides in raw milk samples collected in four important milk-producing regions in Brazil and observe any possible relationship between presence of these compounds and the previously reported absence of Listeria monocytogenes e Salmonella spp. in the same milk samples. Organophosphates and/or carbamates were detected in 196 (93.8% out of 209 samples. For evaluation of the interference of these products on detection of L. monocytogenes and Salmonella spp., 28 milk samples containing these pesticides were boiled for 10 minutes, added of the pathogens, and their multiplication was monitored during storage at 4 °C and 25 °C. No significant differences (p

  19. 气相色谱-串联质谱法测定黄酒和酱油中的氨基甲酸乙酯%Determination of ethyl carbamate in Chinese rice wine and soy sauce by gas chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    徐小民; 何华丽; 阮瑜迪; 黄百芬; 任一平


      目的建立气相色谱-串联质谱法(GC-MS/MS)测定黄酒和酱油中氨基甲酸乙酯的分析方法。方法样品添加同位素内标氨基甲酸乙酯-d5后,直接上样到填装好ExtrelutTM NT有机硅藻土的柱中进行基质固相分散萃取,先用正己烷淋洗除杂,再用乙酸乙酯:乙醚(1:9, v/v)的混合溶剂洗脱氨基甲酸乙酯,洗脱液经浓缩后采用GC-MS/MS多反应监测(MRM)模式测定。结果方法检出限和线性范围分别为2µg/kg和5~1000µg/kg (R>0.999)。在50、200、500µg/kg三个添加水平下,黄酒基体中氨基甲酸乙酯的加标回收率为97.4%~98.8%, RSD为4.0%~8.4%。向酱油基体中添加10、50、200µg/kg 三个浓度水平,氨基甲酸乙酯的加标回收率为96.2%~104.0%, RSD为5.3%~10.0%。结论该方法定量准确、操作简单、灵敏度高、定性确证可靠,适用于黄酒和酱油中氨基甲酸乙酯的测定。%  Objective To establish a method for qualitative and quantitative determination of ethyl carbamate in Chinese rice wine and soy sauce by gas chromatography-tandem mass spectrometry (GC-MS/MS). Methods After spiked with internal standard ethyl carbamate-d5, the sample was directly loaded to an ExtrelutTM NT column for matrix solid-phase dispersion extraction. Hexane was added to wash the matrix interferences and 90% (v/v) ethyl ether/ethyl acetate mixture was used to elute the analyte. The concentrated extract was detected by GC-MS/MS with multiple reaction monitoring (MRM) mode. Results The limit of detection (LOD) was 2 μg/kg and the linear range was 5~1000 µg/kg (R>0.999). For Chinese rice wine, the recoveries at the spiked levels of 50, 200, and 500 µg/kg were 97.4%~98.8%with the RSD of 4.0%~8.4%. For soy sauce, the recoveries at the levels of 10, 50, and 200 µg/kg were 96.2%~104.0% with the RSD of 5.3%~10.0%. Conclusion The method is highly sensitive, easy operating, accurate for quantit-ative analysis, and reliable for qualitative detection

  20. Laboratory Co-toxicity of Cyprodinil and Carbamic Acid Complex against Pathogenic Fungi on Five Kinds of Crops%嘧菌环胺和缬霉威复配对5种作物病原菌的室内联合毒力

    Institute of Scientific and Technical Information of China (English)

    刘润强; 曹前辉; 王清峻; 陈锡岭


    The synergistic activity of cyprodinil and carbamic acid complex against Fusarium oxysporum f. sp. Fragariae,Colletotrichum orbiculare (Berk. & Ment. ) Arx,Plasmopara viticola(Berk. et Curtis) Berl. et de Toni, Pythium aphanidermatum ( Edson) Fitzpatrick and Botrytis cinerea Pers,the pathogenic fungi on 5 kinds of crops,strawberry,watermelon,grape,tobacco,and rose,respectively,was studied based on the mycelial growth method in the laboratory. The bioassay results showed that the EC50 values of cyprodinil against 5 fungi ranged from 0. 19 mg/L to 1. 92 mg/L,and the EC50 values of carbamic acid against 5 fungi ranged from 0. 23 mg/L to 1. 02 mg/L. When the ratio of cyprodinil and carbamic acid was 15:1,the co-toxicity cofficient(CTC) against mycelial growth of Fusarium oxysporum f. sp. Fragariae was maximum ( 217 . 70 );When the ratio of the mixture was 8:1 , the CTC against mycelial growth of Colletotrichum orbiculare (Berk.& Ment. ) Arx was maximum(203. 59); When the ratio of the mixture was 3:1,the CTC against mycelial growth of Pythium aphanidermatum ( Edson) Fitzpatrick was maximum (196. 29);When the ratio of the mixture was 1:6,the CTC against mycelial growth of Plasmopara viticola (Berk. et Curtis) Berl. et de Toni was maximum(201. 98);When the ratio of the mixture was 9:1, the CTC against mycelial growth of Botrytis cinerea Pers was maximum ( 202 . 56 ) . The results suggested that cyprodinil and carbamic acid had significant synergistic activity against 5 different fungi when combined by appropriate ratio.%采用室内菌丝生长速率法,以草莓枯萎病菌、西瓜炭疽病菌、烟草猝倒病菌、葡萄霜霉病菌和月季灰霉病菌为作用目标,研究嘧菌环胺和缬霉威混配对5种病菌的联合毒力,为嘧菌环胺和缬霉威混配使用提供科学依据.结果显示,嘧菌环胺对5种病菌的有效中质量浓度(EC50)为0.19~1.92 mg/L,缬霉威对5种病菌的EC50为0.23~1.02 mg/L;当嘧菌环胺和缬霉威的混配比例为15

  1. 溶剂浮选-气相色谱/质谱法测定蔬菜中氨基甲酸酯类农药残留%Determination of N-Methyl Carbamate Pesticide Residues in Vegetables by the Method of Solvent Sublation followed by GC/MS

    Institute of Scientific and Technical Information of China (English)

    席艳丽; 董慧茹


      建立了一种有效分离富集并检测蔬菜中氨基甲酸酯类农药残留的方法,即采用溶剂浮选法(SS)对蔬菜中的氨基甲酸酯类农药残留进行分离富集,然后用气相色谱/质谱(GC/MS)进行检测.考察了浮选溶剂、试液 pH、通气速度及浮选时间等因素对浮选效果的影响,得到了优化浮选条件;对此条件下的浮选产物进行气相色谱/质谱检测,回收率为81.6%~97.8%,RSD为1.39%~2.65%,定量限(LOQ)为0.39~6.17μg/kg.%  An effective method of solvent sublation followed by GC/MS for separating, enriching and determining of the residue of N-methyl carbamate pesticides in vegetables has been developed. The optimal conditions of the solvent sublation were selected by investigating the effects of organic solvent, pH of the solution, nitrogen flow rate and sublation time on the sublation efficiency of N-methyl carbamate. The recoveries of spiked vegetable samples in the method were from 81.6%to 97.8%, and RSD values were from 1.39%to 2.65%. The limit of quantitation (LOQ) values was in the range of 0.39~6.17μg/kg.

  2. L'acétylcholinestérase des poissons, cible des organophosphorés et des carbamates. Caractérisation du gène et des formes moléculaires de l'enzyme chez Danio rerio. Effets des anticholinestérasiques

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    Full Text Available L'acétylcholinestérase (AChE, EC est une enzyme indispensable de la transmission synaptique cholinergique. Son inhibition par les organophosphorés et les carbamates est à la base de certains traitements insecticides et nématicides utilisés en agriculture. Les faunes sauvage (en particulier les poissons et domestique sont exposées aux résidus des traitements anticholinestérasiques. La mesure de l'inhibition de l'activité AChE chez ces espèces est un marqueur fiable de l'exposition. Ceci est montré ici pour l'AChE de carpes exposées expérimentalement au carbofuran (carbamate. Nous présentons parallèlement des données sur le gène de l'AChE chez Danio rerio et sur les formes moléculaires de l'enzyme chez Danio, Cyprinus carpio et Oncorhynchus mykiss. Contrairement à ce qui est observé chez d'autres vertébrés, le gène d'AChE de Danio ne possède pas d'exon H et seules les sous-unités de type T ont pu être identifiées chez ces trois espèces. Des résultats préliminaires d'hybridation in situ sur les embryons sont présentés et nous discutons l'intérêt des expériences de transgenèse dans l'oeuf de Danio pour étudier d'éventuelles fonctions morphogénétiques de l'AChE au début du développement.

  3. 硝基修饰MOF-5材料的制备及催化氨基甲酸酯热分解%Synthesis of Nitro-modified MOF-5 and Its Application on Catalyzing the Thermal Decomposition of Carbamates

    Institute of Scientific and Technical Information of China (English)

    张毅; 杨先贵; 王庆印; 姚洁; 胡静; 王公应


    Metal-organic frameworks ( MOFs ) are a new class of porous materials that are constructed from transition metal ions and organic ligands, and have potential applications in catalysis, separation and gas storage. MOF-5-NO2 , a metal-organic framework with nitro group, was synthesised by the direct mixing method at room temperature. Characterized by XRD, FTIR, N2 adsorption and SEM, the crystalline structure and morphology of MOF-5-NO2 were found resembled that of MOF-5, and both the MOFs exhibited microporo-sity with high specific surface area. However, the Lewis acidity of MOF-5-NO2 was stronger than that of MOF-5 for the electron withdrawing effect of -NO2 , which was one of the reasons for the high activity of MOF-5-NO2 on the synthesis of isocyanates by the thermal decomposition of carbamates. Under solvent-free condition, MOF-5-NO2 significantly accelerated the reaction rate of the decomposition of methyl N-phenyl car-bamate, and the turnover frequency(TOF) was seven times higher than that on ZnO. The intermediate product of the decomposition of methylene diphenyl di( phenylcarbamate) was decreased, and the yield of methylene diphenyl diisocyanate reached 81.6%. In conclusion, MOF-5-NO2 prepared by the direct mixing method is a very effective catalyst for the thermal decomposition of carbamates, and is potentially better suited for other ca-talyses by modified with appropriate groups.%采用直接混合法在室温下制备了含硝基的金属-有机骨架材料MOF-5-NO2,并采用X射线衍射分析,红外光谱, N2等温吸附和扫描电子显微镜对其进行了表征.结果表明, MOF-5-NO2具有与MOF-5相似的晶体结构和表面形貌,二者都具有高比表面积及微孔特性,但由于硝基的吸电子效应, MOF-5-NO2比MOF-5具有更强的Lewis酸性,因而对氨基甲酸酯热分解制备异氰酸酯的反应具有良好的催化活性.在无溶剂条件下, MOF-5-NO2使苯氨基甲酸甲酯热分解的反应速度显著提高,催

  4. Regulatory effect of arginine metabolism enzymes on ethyl carbamate formation during the fermentation of Chinese yellow rice wine%精氨酸代谢酶对传统黄酒发酵氨基甲酸乙酯产生的调控作用

    Institute of Scientific and Technical Information of China (English)

    方若思; 董亚晨; 徐腾洋; 范琳琳; 陈启和


    Summary Ethyl carbamate ( EC) is a potential carcinogenic compound in most of fermented products . It widely exists in the fermented foods , especially alcohol beverages , such as grape wine , Japanese sake and Chinese yellow rice wine , etc . Thus , the search for effective methods to reduce EC level in final products must be carried on and considered . It has been reported that the optimal production methods for grape wine and high quality strains were capable of reducing the level of EC in grape wine product . Arginine is one of the major amino acids found in grape wine , which can be decomposed to the precursors of EC by yeast and malolactic fermentation bacteria . The degradation of arginine by lactic acid bacteria via the arginine deiminase ( ADI) pathway has been reported . It involves three enzymes: ADI , ornithine transcarbamoylase ( OTC ) and carbamate kinase . The degradation of arginine metabolism produced ammonia , adenosine triphosphate , ornithine , carbamyl phosphate and some citrullines . Studies have shown that citrulline is a typical indicator of EC level in grape wine , and a correlation between citrulline production and ethyl carbamate formation by L actobacillus hilgardii isolated from grape wines is reported . As generally acknowledged , urea is considered as the major precursor of EC production in grape wine fermentation which can be degraded by urease .In this study , different disposals were taken during the brewing process . The control group was designed without adding any inhibitor , whereas in the experimental groups , 0 .001 , 0 .01 , 0 .2 mol/L L‐ornithine hydrochlorides were added , and 150 , 750 U ureases per 1 .5 kg solid at the eighth day were added as inhibitors , respectively . As a result , both the inhibitors acted well . The highest level of EC content in control group was 169 mg/L , while in the experimental groups with 0 .01mol/L L‐ornithine hydrochloride and 150 U urease , the EC contents were 78 .81 and 58 .55 mg

  5. The Measurement of Ethyl Carbamate Content in Alcoholic Beverage in Guangzhou by GC-MS with Internal Standard Method%气相色谱-质谱联用内标法检测广州市场饮料酒中氨基甲酸乙酯含量的研究

    Institute of Scientific and Technical Information of China (English)

    王浩; 刘丽斌; 黄秋婷; 丁怡; 彭程; 刘妙芬; 黄惠华


    In order to measure the content of ethyl carbamate (EC) in low-end alcoholic beverage in Guangzhou market, gas chromatography-mass spectrometry (GC-MS) with internal standard method was adopted in the experiments (solid phase extraction used for wine samples pre-treatment and D5-ethyl carbamate used as the internal standard). The results suggested that, the linear correlation coefficient was 0.9996 within EC concentration range of 20μg/L to 200μg/L, the detection limit was 0.0018 mg/kg, the recoveries and RSD were 75.90%~103.23%and 1.43%~3.95%respectively. Among all the alcoholic samples, no EC detected in beer and in rice wine, other alcoholic beverages contained EC more or less (the average EC content in brandy>in plum wine>in yellow rice wine>in liquor>in medicinal wine>in fruit wine>in grape wine).%为研究和调查广州市场在售中低端酒中的氨基甲酸乙酯含量,采用固相萃取方式对酒样进行前处理, D5-氨基甲酸乙酯为内标,使用气相色谱串联质谱(GC-MS)定量测定含量。结果表明,在20~200μg/L浓度范围内线性相关系数为0.9996,检出限为0.0018 mg/kg,回收率在75.90%~103.23%之间,精密度在1.43%~3.95%。具有良好的重现性。所有样品中,啤酒和米酒未检出,其他各种酒精饮料中都含有一定量的氨基甲酸乙酯,平均含量大小依次为白兰地>梅酒>黄酒>白酒>药酒>果酒>葡萄酒。

  6. Microwave Assisted Synthesis of Carbamate-type Molecular Tweezers Based on Hyodeoxycholic Acid and Their Recognition on Halogen Anions%氨基甲酸酯型猪去氧胆酸分子钳的微波合成及其对卤素阴离子的识别

    Institute of Scientific and Technical Information of China (English)

    曾碧涛; 周黎军; 李相彪; 赵先明; 赵志刚


    Five novel carbamate-type molecular tweezers (4a ~ 4e) based on hyodeoxycholic acid were synthesized using hyodeoxycholic acid as spacer to bridge different aromatic amines under microwave irradiation. The structures were characterized by ' H NMR, IR, MS and elemental analysis. The recognition properties of 4 on halogen anions were investigated by UV-Vis titration method. The results showed that 4 not only formed 1 :1 complex with halogen anions, but also exhibited good selectivity for halogen anions with selective sequence of I- > Br- > Cl-.%在微波辐射条件下,以猪去氧胆酸为隔离基,芳香胺为手臂,通过三光气桥连,合成了五个新型猪去氧胆酸分子钳(4a~4e),其结构经1H NMR,IR,MS和元素分析表征.紫外光谱滴定法的研究结果表明,4对卤素阴离子均具有良好的识别能力,选择顺序依次为I-> Br-> Cl-;主客体之间形成1∶1型超分子配合物,识别作用的主要推动力为氢键.

  7. Organophosphate and carbamate poisonings in the northwest of Paraná state, Brazil from 1994 to 2005: clinical and epidemiological aspects Intoxicações por inseticidas organofosforados e carbamatos no noroeste do Paraná, Brasil, de 1994 a 2005: aspectos clínicos e epidemiológicos

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    Alexandre Ferreira


    Full Text Available In the present study, clinical and epidemiological aspects of 529 intoxication cases of organophosphate or carbamate pesticides in the northwest of the state of Paraná, Brazil, over a twelve-year period (1994-2005, are presented. One hundred-five of 257 patients (40.8% who attempted suicide were admitted to Intensive Care Units (ICUs, with an average hospital stay of two days (range 1-40 days. Men corresponded to 56.4% of the cases of suicide attempts and sixteen individuals died. One hundred-forty patients intoxicated due to occupational exposure were all young adults and nine of them were admitted to ICU, with average hospital stays of eight days (range 1-16 days. Of these cases, two patients died. One hundred twenty-four patients intoxicated due to accidental exposure were mainly children and had a hospital average stay of four days. Twenty patients were admitted to the ICU, and one of them died. Overall complications included respiratory failure, convulsions, and aspiration pneumonia. Deliberate ingestion of organophosphates and carbamates was much more toxic than occupational and accidental exposure. Men aged 15-39 years were the most likely to attempt suicide with these agents and had more prolonged ICU with significant complications and mortality.No presente estudo são apresentados aspectos clínicos e epidemiológicos de 529 casos de intoxicação por inseticidas organofosforados e carbamatos ocorridos na região noroeste do Estado do Paraná, Brasil, no período de 1994 a 2005. A saber, 105 pessoas de 257 pacientes (40,8% que tentaram suicídio foram admitidas na Unidade de Tratamento Intensivo (UTI, com média de estadia hospitalar de 2 dias (de 1 a 40 dias. Pacientes do sexo masculino corresponderam a 56,4% dos casos de tentativa de suicídio e 16 indivíduos morreram. Todos os 140 pacientes intoxicados devido à exposição ocupacional eram adultos e 9 foram admitidos na UTI, com média de estadia hospitalar de 8 dias (de 1 a 16

  8. Bis{(E-3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropan-1-aminium} bis[μ-(E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamido(2−]bis{[(E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide]copper(II} bis((E-{3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropyl}carbamate acetonitrile disolvate

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    Andrii I. Buvailo


    Full Text Available The reaction between copper(II nitrate and (E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide led to the formation of the dinuclear centrosymmetric copper(II title complex, (C8H18N3O22[Cu2(C8H15N3O22(C8H17N3O22](C9H16N3O42·2CH3CN, in which an inversion center is located at the midpoint of the Cu2 unit in the center of the neutral [Cu2(C8H15N3O22(C8H17N3O22] complex fragment. The Cu2+ ions are connected by two N—O bridging groups [Cu...Cu separation = 4.0608 (5 Å] while the CuII ions are five-coordinated in a square-pyramidal N4O coordination environment. The complex molecule co-crystallizes with two molecules of acetonitrile, two molecules of the protonated ligand (E-3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropan-1-aminium and two negatively charged (E-{3-[2-(hydroxyiminopropanamido]-2,2-dimethylpropyl}carbamate anions, which were probably formed as a result of condensation between (E-N-(3-amino-2,2-dimethylpropyl-2-(hydroxyiminopropanamide and hydrogencarbonate anions. In the crystal, the complex fragment [Cu2(C8H15N3O22(C8H17N3O22] and the ion pair C8H18N3O2+.C9H16N3O4− are connected via an extended system of hydrogen bonds.

  9. Comparison of different pretreatment methods for determination of ethyl carbamate in wine by gas chromatography-mass spectrometry%气相色谱-质谱检测葡萄酒中氨基甲酸乙酯预处理方法的比较研究

    Institute of Scientific and Technical Information of China (English)

    章晴; 陈士恒; 史晓梅; 杨永坛


    目的:比较液液萃取法、固相萃取法和分散式固相萃取法作为预处理方法对葡萄酒中的氨基甲酸乙酯的处理效率。方法葡萄酒样品中的氨基甲酸乙酯分别用二氯甲烷进行液液萃取,用氨基甲酸乙酯专用柱进行固相萃取,用乙腈、石墨化炭黑和N-丙基乙二胺进行分散式固相萃取,再以气相色谱-质谱联用仪测定其含量。结果3种预处理方法的平均回收率均在70%~110%之间,相对标准偏差(n=5)均小于6%。液液萃取法处理单个样品成本小于5元,富集倍数可达5倍,可用于低含量样品的预处理和进出口企业的产品合规性检测;固相萃取法操作简便,每人每工作日可处理40个样品,可用于企业的高通量检测;分散式固相萃取法成本适中、回收率最佳、综合预处理效率高,一次预处理可同时检测葡萄酒中农药残留和氨基甲酸乙酯含量,适用于葡萄酒中多种危害物质的筛查。结论三种方法各具优势,综合考虑处理效率和实验成本,分散式固相萃取法更适合葡萄酒生产企业的日常应用。该方法已用于葡萄酒中氨基甲酸乙酯的含量测定。%Objective To compare the preconditioning efficiencies of ethyl carbamate in wine by liquid-liquid extraction (LLE), solid phase extraction (SPE) and dispersive solid phase extraction (d-SPE). MethodThree methods of LLE with dichloromethane, SPE with Cleanert EC column and d-SPE with acetonitrile, graphitized carbon and primary secondary amine were separately used to extract the ethyl carbamate of the wine samples, which was analyzed by gas chromatography-mass spectrometry (GC-MS) in selected ion monitoring mode.Result The spiked recoveries at 3 levels of these methods were in the range of 70%~110% and the relative standard deviations (n=5) were less than 6%, indicating that those methods had a good accuracy and precision. Since it was low-cost and had a high enrichment

  10. Adsorption Kinetics of Carbamate Pesticide in Rice Field Soil

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    Soontree Khuntong


    Full Text Available Ultrasonic extraction (75.55% with petroleum ether:acetone (1:1, v/v was employed for extraction of carbofuran in rice field soil. The amounts of carbofuran were determined by reverse phase HPLC. The analytical method provided high precision and accuracy with the relative error of 0.47%. The percentage of recoveries varied from 84% to 77% in the con¬centration ranges of 10–40 mg/L of spiked soil samples. The carbofuran residues in the rice field soil significantly decreased year by year because of pesticide properties, soil properties and degradation conditions. A high amount of residues was found in the plots that contained high organic contents. The adsorption of carbofuran in soil reached equilibrium within 23 h. The percentage of adsorption varied from almost 30% to 80% depending on concentrations of carbofuran. The adsorption of carbofuran agreed with Freundlich isotherms; q = 7.07 x 10-5Cf2.5092; with the correlation coefficient of 0.9281. Organic carbon coefficient, Koc, was 1.91 x 10-3 mg/L calculated from Kd, and half-life (8.9 d of adsorbed carbofuran. The GUS index (6.37 calculated from Koc presented a high lixiviation potential. The positive ΔG indicated the non-spontaneous reaction. Carbofuran rapidly desorbed from soil at the desorption rate of 0.0228 mg/kg soil d. Kinetic studies provided the first order reaction with the reaction rate of 0.0779 mg/d and half-life of 8.9 days.

  11. New water-soluble carbamate ester derivatives of resveratrol


    Andrea Mattarei; Massimo Carraro; Michele Azzolini; Cristina Paradisi; Mario Zoratti; Lucia Biasutto


    Low bioavailability severely hinders exploitation of the biomedical potential of resveratrol. Extensive phase-II metabolism and poor water solubility contribute to lowering the concentrations of resveratrol in the bloodstream after oral administration. Prodrugs may provide a solution—protection of the phenolic functions hinders conjugative metabolism and can be exploited to modulate the physicochemical properties of the compound. We report here the synthesis and characterization of carb...

  12. Fluorimetric Determination of Carbamate Pesticides in Host-Guest Complexes

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    Alicia Viviana Veglia


    Full Text Available From the effect of β-cyclodextrin and hydroxypropyl-β-cyclodextrin on the UVvisible and fluorescence spectra of carbaryl and carbofuran, the values of association constants were determined. The ratio of the fluorescence quantum yields for the bound and free substrates indicated an enhanced fluorimetric method of detection.

  13. Medical treatment of acute poisoning with organophosphorus and carbamate pesticides. (United States)

    Jokanović, Milan


    Organophosphorus compounds (OPs) are used as pesticides and developed as warfare nerve agents such as tabun, soman, sarin, VX and others. Exposure to even small amounts of an OP can be fatal and death is usually caused by respiratory failure. The mechanism of OP poisoning involves inhibition of acetylcholinesterase (AChE) leading to inactivation of the enzyme which has an important role in neurotransmission. AChE inhibition results in the accumulation of acetylcholine at cholinergic receptor sites, producing continuous stimulation of cholinergic fibers throughout the nervous systems. During more than five decades, pyridinium oximes have been developed as therapeutic agents used in the medical treatment of poisoning with OP. They act by reactivation of AChE inhibited by OP. However, they differ in their activity in poisoning with pesticides and warfare nerve agents and there is still no universal broad-spectrum oxime capable of protecting against all known OP. In spite of enormous efforts devoted to development of new pyridinium oximes as potential antidotes against poisoning with OP only four compounds so far have found its application in human medicine. Presently, a combination of an antimuscarinic agent, e.g. atropine, AChE reactivator such as one of the recommended pyridinium oximes (pralidoxime, trimedoxime, obidoxime and HI-6) and diazepam are used for the treatment of OP poisoning in humans. In this article the available data related to medical treatment of poisoning with OP pesticides are reviewed and the current recommendations are presented.

  14. Transdermal carbamate poisoning – a case of misuse

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    Lalit Kumar Rajbanshi


    Full Text Available Acute pesticide poisoning is a common mode of intentional self harm. Oral ingestion is the usual mode of poisoning. However, inhalation, accidental or occupational transdermal exposure leading to acute or chronic poisoning can be the other route of poisoning. It has been seen that the purpose of poising is suicidal intensity in most of the cases. We report an unusual case where the victim had acute pesticide poisoning through transdermal route that was intended for non suicidal purpose. The patient was managed successfully with immediate decontamination and adequate antidote.

  15. Bis-{(E)-3-[2-(hy-droxy-imino)-propan-amido]-2,2-dimethyl-propan-1-aminium} bis[μ-(E)-N-(3-amino-2,2-dimethyl-prop-yl)-2-(hy-droxy-imino)-propanamido-(2-)]bis-{[(E)-N-(3-amino-2,2-dimethyl-prop-yl)-2-(hy-droxy-imino)-propanamide]-copper(II)} bis-((E)-{3-[2-(hy-droxy-imino)-propanamido]-2,2-dimethyl-prop-yl}carbamate) acetonitrile disolvate. (United States)

    Buvailo, Andrii I; Pavlishchuk, Anna V; Penkova, Larysa V; Kotova, Natalia V; Haukka, Matti


    The reaction between copper(II) nitrate and (E)-N-(3-amino-2,2-dimethyl-prop-yl)-2-(hy-droxy-imino)-propanamide led to the formation of the dinuclear centrosymmetric copper(II) title complex, (C8H18N3O2)2[Cu2(C8H15N3O2)2(C8H17N3O2)2](C9H16N3O4)2·2CH3CN, in which an inversion center is located at the midpoint of the Cu2 unit in the center of the neutral [Cu2(C8H15N3O2)2(C8H17N3O2)2] complex fragment. The Cu(2+) ions are connected by two N-O bridging groups [Cu⋯Cu separation = 4.0608 (5) Å] while the Cu(II) ions are five-coordinated in a square-pyramidal N4O coordination environment. The complex mol-ecule co-crystallizes with two mol-ecules of acetonitrile, two mol-ecules of the protonated ligand (E)-3-[2-(hy-droxy-imino)-propanamido]-2,2-dimethyl-propan-1-aminium and two negatively charged (E)-{3-[2-(hy-droxy-imino)-propanamido]-2,2-dimethyl-prop-yl}carbamate anions, which were probably formed as a result of condensation between (E)-N-(3-amino-2,2-dimethyl-prop-yl)-2-(hy-droxy-imino)-propanamide and hydro-gencarbonate anions. In the crystal, the complex fragment [Cu2(C8H15N3O2)2(C8H17N3O2)2] and the ion pair C8H18N3O2(+.)C9H16N3O4(-) are connected via an extended system of hydrogen bonds.

  16. 化学发光生物传感器法测定食品中有机磷与氨基甲酸酯类农药残留%Determination of organophosphorus and carbamates pesticide residues in foods by chemiluminescence biosensor

    Institute of Scientific and Technical Information of China (English)

    王晓朋; 曾梅; 万德慧; 唐晗; 赵彬媛; 周雅倩; 刘晓宇


    Objective To create a high-sensitivity biosensor for detecting organophosphorus and carbamates pesticides in foods and establish a new method to determine these two kinds of pesticides.Methods Immobilized acetylcholinesterase (AchE) was used as recognition element of the sensor, reacting specifically with the substrate of acetylthiocholine iodide(ATCI), the micro-fluidic chip with CL analyzer was used as detecting element, and luminol-potassium ferricyanide system was used in chemiluminescence system. ResultsWhen the concentration of proximal, dichlorvos, dimethoate ranging from 0.1~10, 0.08~10, and 0.8~15μg/mL, respectively, the correlation coefficients were 0.9923, 0.9903, and 0.9904, and the detection limits were 0.047, 0.054, and 0.388μg/mL, respectively. When the concentrations of carbofuran, carbonyl, and methomyl were ranging from 0.08~15, 0.1~10, and 0.1~10μg/mL, respectively, the correlation coefficients were 0.9926, 0.9972, and 0.9944, and the detection limits were 0.049, 0.051, and 0.080μg/mL, respectively. The evaluation of biosensor performance indicates good precision, when determining all 6 kinds of pesticides under optimal conditions, RSD was below 7%; when the substrate of ATCI was injected into chemiluminescence system 6 times discontinuously, RSD was below 8%, which indicated good stability; immobilized AChE was stored in phosphate buffer(pH=8.0), detecting activity every 10 d, lasting for two months, the relative enzymatic activity decreased only 23%, indicating a good storage stability; the biosensor was used to detect samples of cabbage and apple, fortified recoveries were between 90%~99%.Conclusion This biosensor has a good performance, therefore it can be used to determine pesticides in foods.%目的:构建一种用于检测食品中有机磷与氨基甲酸酯类农药残留的高灵敏度生物传感器,建立一种用于测定食品中两类农药残留的新方法。方法以固定化乙酰胆碱酯酶(AChE

  17. Bis­{(E)-3-[2-(hy­droxy­imino)­propan­amido]-2,2-dimethyl­propan-1-aminium} bis[μ-(E)-N-(3-amino-2,2-dimethyl­prop­yl)-2-(hy­droxy­imino)­propanamido­(2−)]bis­{[(E)-N-(3-amino-2,2-dimethyl­prop­yl)-2-(hy­droxy­imino)­propanamide]­copper(II)} bis­((E)-{3-[2-(hy­droxy­imino)­propanamido]-2,2-dimethyl­prop­yl}carbamate) acetonitrile disolvate (United States)

    Buvailo, Andrii I.; Pavlishchuk, Anna V.; Penkova, Larysa V.; Kotova, Natalia V.; Haukka, Matti


    The reaction between copper(II) nitrate and (E)-N-(3-amino-2,2-dimethyl­prop­yl)-2-(hy­droxy­imino)­propanamide led to the formation of the dinuclear centrosymmetric copper(II) title complex, (C8H18N3O2)2[Cu2(C8H15N3O2)2(C8H17N3O2)2](C9H16N3O4)2·2CH3CN, in which an inversion center is located at the midpoint of the Cu2 unit in the center of the neutral [Cu2(C8H15N3O2)2(C8H17N3O2)2] complex fragment. The Cu2+ ions are connected by two N—O bridging groups [Cu⋯Cu separation = 4.0608 (5) Å] while the CuII ions are five-coordinated in a square-pyramidal N4O coordination environment. The complex mol­ecule co-crystallizes with two mol­ecules of acetonitrile, two mol­ecules of the protonated ligand (E)-3-[2-(hy­droxy­imino)­propanamido]-2,2-dimethyl­propan-1-aminium and two negatively charged (E)-{3-[2-(hy­droxy­imino)­propanamido]-2,2-dimethyl­prop­yl}carbamate anions, which were probably formed as a result of condensation between (E)-N-(3-amino-2,2-dimethyl­prop­yl)-2-(hy­droxy­imino)­propanamide and hydro­gencarbonate anions. In the crystal, the complex fragment [Cu2(C8H15N3O2)2(C8H17N3O2)2] and the ion pair C8H18N3O2 +.C9H16N3O4 − are connected via an extended system of hydrogen bonds. PMID:23468704

  18. Genetic Study of Propoxur Resistance—A Carbamate Insecticide in the Malaria Mosquito, Anopheles stephensi Liston

    Directory of Open Access Journals (Sweden)

    D. Sanil


    Full Text Available Anopheles stephensi Liston (Diptera: Culicidae is the urban vector of malaria in the Indian subcontinent and several countries of the Middle East. The genetics of propoxur resistance (pr in An. stephensi larvae was studied to determine its mode of inheritance. A diagnostic dose of 0.01 mg/L as recommended by WHO was used to establish homozygous resistant and susceptible strains. Reciprocal crosses between the resistant and susceptible strains showed an F1 generation of incomplete dominance. The progenies of backcrosses to susceptible parents were in 1 : 1 ratio of the same phenotypes as the parents and hybrids involved. The dosage mortality (d-m lines were constructed for each one of the crosses, and the degree of dominance was calculated. It is concluded that propoxur resistance in An. stephensi larvae is due to monofactorial inheritance with incomplete dominance and is autosomal in nature.

  19. Carbamate-directed benzylic lithiation for the diastereo- and enantioselective synthesis of diaryl ether atropisomers

    Directory of Open Access Journals (Sweden)

    Abigail Page


    Full Text Available Diaryl ethers carrying carbamoyloxymethyl groups may be desymmetrised enantio- and diastereoselectively by the use of the sec-BuLi–(−-sparteine complex in diethyl ether. Enantioselective deprotonation of one of the two benzylic positions leads to atropisomeric products with ca. 80:20 e.r.; an electrophilic quench typically provides functionalised atropisomeric diastereoisomers in up to 97:3 d.r.


    Directory of Open Access Journals (Sweden)

    Dilara Islam Sharif


    Full Text Available A bacterial species having the ability to grow in the presence of carbosulfan pesticide “Marshall” was isolated from Solanum melongena (brinjal cultivated soil in Khulna region, Bangladeh, having a history of pesticide usage. The strain was morphologically and biochemically identified to belong to the genera Pseudomonas. A comparative study of growth of this strain with other isolated bacteria showed its ability to grow in the presence of different concentrations of Marshall. The susceptibility of the stain to Marshall was also assessed through disk diffusion assay which showed the strain to be resistant at concentrations of Marshal commonly used under field conditions. The selected strain also showed its capability to degrade Marshall through observed characteristics on sublimated agar plates. The biodegradation capability of the strain isolated in this study can be valuable for further study towards bioremediation of pesticide contaminated soils.


    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  2. 76 FR 34200 - Land Disposal Restrictions: Revision of the Treatment Standards for Carbamate Wastes (United States)


    .... However, the lack of readily available analytical standards makes it difficult to measure whether the... total of 2 copies. Hand Delivery: Please deliver 2 copies to the EPA Docket Center (EPA/DC), EPA West... intended to be discarded. This action is being taken because there may be no analytical standards...

  3. Photoenhanced toxicity of a carbamate insecticide to early life stage anuran amphibians (United States)

    Zaga, A.; Little, E.E.; Rabeni, C.F.; Ellersieck, Mark R.


    African clawed frog (Xenopus laevis) and gray tree frog (Hyla versicolor) embryos and tadpoles were exposed to sublethal levels of carbaryl, a broad-spectrum insecticide, and ultraviolet radiation to determine interactive and sublethal effects. Ultraviolet intensity (UV-B [285-320 nm] plus LIV-A [321-400 nm]) was controlled with various types of plastic filters and quantified with a scanning spectroradiometer. Significant differences in swimming activity and mortality of both species were evident during the 96-h experiments. Ultraviolet-B radiation alone and carbaryl in the presence of UV-B significantly decreased swimming activity of both species. As little as 1.5% intensity of ambient solar UV-B radiation photoactivated carbaryl. Toxicity of 7.5 mg/L earbaryl increased by 10-fold in the presence of UV-B in all species and life stages tested. Our results indicate that photoenhancement by solar UV-B radiation should be considered when evaluating the toxicity of contaminants to amphibians and other organisms.

  4. Effect of Carbamate, Organophosphate, and Avermectin Nematicides on Oxygen Consumption by Three Meloidogyne spp. (United States)

    Nordmeyer, D; Dickson, D W


    Second-stage juveniles (I2) of Meloidogyne arenaria consumed more oxygen (P nematicide used. Except for aldicarb, there was no differential sensitivity among the three nematode species. Meloidogyne javanica had a greater percentage decrease (P nematicides were positively correlated (P

  5. Zwitterionic Cellulose Carbamate with Regioselective Substitution Pattern: A Coating Material Possessing Antimicrobial Activity. (United States)

    Elschner, Thomas; Lüdecke, Claudia; Kalden, Diana; Roth, Martin; Löffler, Bettina; Jandt, Klaus D; Heinze, Thomas


    A polyzwitterion is synthesized by regioselective functionalization of cellulose possessing a uniform charge distribution. The positively charged ammonium group is present at position 6, while the negative charge of carboxylate is located at positions 2 and 3 of the repeating unit. The molecular structure of the biopolymer derivative is proved by NMR spectroscopy. This cellulose-based zwitterion is applied to several support materials by spin-coating and characterized by means of atomic force microscope, contact angle measurements, ellipsometry, and X-ray photoelectron spectroscopy. The coatings possess antimicrobial activity depending on the support materials (glass, titanium, tissue culture poly(styrene)) as revealed by confocal laser scanning microscopy and live/dead staining.

  6. Intensification of degradation of methomyl (carbamate group pesticide) by using the combination of ultrasonic cavitation and process intensifying additives. (United States)

    Raut-Jadhav, Sunita; Pinjari, Dipak V; Saini, Daulat R; Sonawane, Shirish H; Pandit, Aniruddha B


    In the present work, the degradation of methomyl has been carried out by using the ultrasound cavitation (US) and its combination with H2O2, Fenton and photo-Fenton process. The study of effect of operating pH and ultrasound power density has indicated that maximum extent of degradation of 28.57% could be obtained at the optimal pH of 2.5 and power density of 0.155 W/mL. Application of US in combination with H2O2, Fenton and photo-Fenton process has further accelerated the rate of degradation of methomyl with complete degradation of methomyl in 27 min, 18 min and 9 min respectively. Mineralization study has proved that a combination of US and photo-Fenton process is the most effective process with maximum extent of mineralization of 78.8%. Comparison of energy efficiency and cost effectiveness of various processes has indicated that the electrical cost of 79892.34Rs./m(3) for ultrasonic degradation of methomyl has drastically reduced to 2277.00Rs./m(3), 1518.00Rs./m(3) and 807.58Rs./m(3) by using US in combination with H2O2, Fenton and photo-Fenton process respectively. The cost analysis has also indicated that the combination of US and photo-Fenton process is the most energy efficient and cost effective process.

  7. Adsorption of toxic carbamate pesticide oxamyl from liquid phase by newly synthesized and characterized graphene quantum dots nanomaterials. (United States)

    Agarwal, Shilpi; Sadeghi, Nima; Tyagi, Inderjeet; Gupta, Vinod Kumar; Fakhri, Ali


    Graphene quantum dots have been synthesized using the microwave-assisted hydrothermal route. The surface textural and morphological structure of synthesized adsorbent i.e. graphene quantum dots was analyzed using various analytical techniques such as X-ray diffraction, Transmission electron Microscopy, Atomic Force Microscopy and N2 adsorption-desorption instrumental techniques. The application of graphene quantum dots as an adsorbent for the removal of noxious pesticide compound i.e. oxamyl from aqueous solutions was well investigated and elucidated. The impact of several effective parameters such as effect of agitation speed, pH, adsorbent dose, contact time, temperature and initial concentration on sorption efficiency was studied and optimized using batch adsorption experiments. The optimized pH for maximum oxamyl adsorption was found to be 8.0 and for the maximum adsorption rates the adsorbent dose of 0.6g was found to be optimum to carry out the adsorption with in less than 25min of contact time. From the results obtained, it is clear that for all contact times, an increase in oxamyl concentration resulted in increase in the percent oxamyl removal. The adsorption equilibrium and kinetic data were well fitted and found to be in good agreement with the Langmuir isotherm and pseudo-second-order kinetic model.

  8. The inhibition of tissue respiration and alcoholic fermentation at different catabolic levels by ethyl carbamate (urethan) and arsenite

    NARCIS (Netherlands)

    Florijn, E.; Gruber, M.; Leijnse, B.; Huisman, T.H.J.


    1. A hypothesis is given concerning the action of urethan and arsenite on malignant growth. Two assumptionsares made:- (a) the enzyme system responsible for energy production in malignant tumours is working at maximal rate, contrary to the corresponding enzyme system in normal tissues. (b) a give


    We have reported that treatment with carbaryl may alter Theta activity in the EEG (Lyke et al., Toxicologist, 108(S-1):441, 2009). In this study, we examined the ability to detect changes in EEG activity produced by pesticides with different modes of action. Long Evans rats were ...

  10. Molecular Targets and Synaptic Effects of Carbamates, Organophosphates, Oximes, and Pyridiniums: Implications for Prophylaxis and Therapy of Organophosphate Toxicity (United States)


    Biandini. G , and Suarez- Isla . Bi. A., 1978, The as~elyh~toline receptor as part of a protein complex in rec~eplor-enriclted ineinbratio fraginrints...facilities. We thank Mr. Luis * A. C. Pou for electronic engineering andi computer expertise, Ms. Maria Estela S. Silva for technical help, and Ms. Mabel currents in cultured human nmuscle. J. Netrohci. 2:1465- nal perfusion of QX-314 have been reported (26). 1473 (1982). 1.Soarer- Isla . BI. A

  11. Possible mechanisms for sensitivity to organophosphorus and carbamate insecticides in eastern screech-owls and American kestrels (United States)

    Vyas, N.B.; Thiele, L.A.; Garland, S.C.


    Effects of a single dietary exposure to fenthion and carbofuran on the survival, feeding behavior and brain ChE activity of eastern screech-owls, Otus asio and American kestrels, Falco sparverius, were evaluated. Birds were exposed to fenthion (23.6189.0 ppm) or carbofuran (31.7253.6 ppm) via meatballs. Carbofuran-exposed owls ate either = 80% of the meatball whereas all kestrels ate depression in determining the sensitivity of an animal may be species-specific.

  12. Salicylanilide carbamates: Promising antibacterial agents with high in vitro activity against methicillin-resistant Staphylococcus aureus (MRSA). (United States)

    Zadrazilova, Iveta; Pospisilova, Sarka; Masarikova, Martina; Imramovsky, Ales; Ferriz, Juana Monreal; Vinsova, Jarmila; Cizek, Alois; Jampilek, Josef


    A series of twenty-one salicylanilide N-alkylcarbamates was assessed for novel antibacterial characteristics against three clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and S. aureus ATCC 29213 as the reference and quality control strain. The minimum inhibitory concentration was determined by the broth dilution micro-method with subsequent subcultivation of aliquots to assess minimum bactericidal concentration. The bactericidal kinetics was established by time-kill assay. Ampicillin, ciprofloxacin and vancomycin were used as reference antibacterial drugs. All the tested compounds exhibited highly potent anti-MRSA activity (⩽ 0.008-4 μg/mL) comparable or up to 250× higher than that of vancomycin, the standard in the treatment of serious MRSA infections. 4-Chloro-2-(3,4-dichlorophenylcarbamoyl)phenyl butylcarbamate and 4-chloro-2-(3,4-dichlorophenylcarbamoyl)phenyl ethylcarbamate were the most active compounds. In most cases, compounds provided reliable bacteriostatic activity, except for 4-chloro-2-(4-chlorophenylcarbamoyl)phenyl decylcarbamate exhibiting bactericidal effect at 8h (for clinical isolate of MRSA 63718) and at 24h (for clinical isolates of MRSA SA 630 and MRSA SA 3202) at 4× MIC. Structure-activity relationships are discussed.

  13. Evaluation of Alternatives to Carbamate and Organophosphate Insecticides Against Thrips and Tomato Spotted Wilt Virus in Peanut Production. (United States)

    Marasigan, K; Toews, M; Kemerait, R; Abney, M R; Culbreath, A; Srinivasan, R


    Thrips are important pests of peanut. They cause severe feeding injuries on peanut foliage in the early season. They also transmit Tomato spotted wilt virus (TSWV), which causes spotted wilt disease. At-plant insecticides and cultivars that exhibit field resistance to TSWV are often used to manage thrips and spotted wilt disease. Historically, peanut growers used the broad-spectrum insecticides aldicarb (IRAC class 1A; Temik) and phorate (IRAC class 1B; Thimet) for managing thrips and thereby reducing TSWV transmission. Aldicarb has not been produced since 2011 and its usage in peanut will be legally phased out in 2018; therefore, identification of alternative chemistries is critical for thrips and spotted wilt management. Here, eight alternative insecticides, with known thrips activity, were evaluated in field trials conducted from 2011 through 2013. In addition, different application methods of alternatives were also evaluated. Imidacloprid (Admire Pro), thiamethoxam (Actara), spinetoram (Radiant), and cyantraniliprole (Exirel) were as effective as aldicarb and phorate in suppressing thrips, but none of the insecticides significantly suppressed spotted wilt incidence. Nevertheless, greenhouse assays demonstrated that the same alternative insecticides were effective in suppressing thrips feeding and reducing TSWV transmission. Spotted wilt incidence in the greenhouse was more severe (∼80%) than in the field (5–25%). In general, field resistance to TSWV in cultivars only marginally influenced spotted wilt incidence. Results suggest that effective management of thrips using alternative insecticides and subsequent feeding reduction could improve yields under low to moderate virus pressure.

  14. Stereoselective synthesis of highly substituted bicyclic γ-lactones using homoaldol addition of 1-(1-cycloalkenyl)methyl carbamates

    DEFF Research Database (Denmark)

    Özlügedik, M.; Kristensen, Jesper Langgaard; Reuber, J.;


    Stereoselective addition of aldehydes 4 to metallated 1-(1-cycloalkenyl) methyl N,N-diisopropylcarbamates 1 gave cyclic homoaldol adducts 6. By applying the (-)-sparteine method, enantiomerically enriched products were obtained. These were oxidatively cyclized to diastereomerically pure ¿-lactone...

  15. A study on the effects of golf course organophosphate and carbamate pesticides on endangered, cave-dwelling arthropods Kauai, Hawaii (United States)

    US Fish and Wildlife Service, Department of the Interior — Three endemic species, two arthropods and one isopod, are present in the Kauai caves. These species are critical components of the cave ecosystems and are possibly...

  16. The effects of isopropyl N-phenyl carbamate on the green alga Oedogonium cardiacum. I. Cell division. (United States)

    Coss, R A; Pickett-Heaps, J D


    Cell division in vegetative filaments of the green alga Oedogonium cardiacum is presented as an experimental system. We report on how we have used this system to study the effects of isopropyl N-phenylcarbamate (IPC) on the mitotic apparatus and on the phycoplast, a planar array of cytokinetic microtubules. Polymerization of microtubules was prevented when filaments, synchronized by a light/dark regime and chilled (2 degrees C) while in metaphase or just before phycoplast formation, were exposed to 5.5 x 10(-4) M IPC and then returned to room temperature. Spindles reformed or phycoplasts formed when these filaments were transferred to growth medium free of IPC. However, the orientation of both microtubular systems was disturbed: the mitotic apparatus often contained three poles, frequently forming three daughter nuclei upon karyokinesis; the phycoplast was often stellate rather than planar, and it sometimes was displaced to the side of both daughter nuclei, resulting in a binucleate and an anucleate cell upon cytokinesis. Our results suggest that IPC (a) prevents the assembly of microtubules, (b) increases the number of functional polar bodies, and (c) affects the orientation of microtubules in O. cardiacum. High voltage (1,000 kV) electron microscopy of 0.5-microm thick sections allowed us to visualize the polar structures, which were not discernible in thin sections.

  17. Point mutations associated with organophosphate and carbamate resistance in Chinese strains of Culex pipiens quinquefasciatus (Diptera: Culicidae.

    Directory of Open Access Journals (Sweden)

    Minghui Zhao

    Full Text Available Acetylcholinesterase resistance has been well documented in many insects, including several mosquito species. We tested the resistance of five wild, Chinese strains of the mosquito Culex pipiens quinquefasciatus to two kinds of pesticides, dichlorvos and propoxur. An acetylcholinesterase gene (ace1 was cloned and sequenced from a pooled sample of mosquitoes from these five strains and the amino acids of five positions were found to vary (V185M, G247S, A328S, A391T, and T682A. Analysis of the correlation between mutation frequencies and resistance levels (LC50 suggests that two point mutations, G247S (r2 = 0.732, P = 0.065 and A328S (r2 = 0.891, P = 0.016, are associated with resistance to propoxur but not to dichlorvos. Although the V185M mutation was not associated with either dichlorvos or propoxur resistance, its RS genotype frequency was correlated with propoxur resistance (r2 = 0.815, P = 0.036. And the HWE test showed the A328S mutation is linked with V185M, also with G247S mutation. This suggested that these three mutations may contribute synergistically to propoxur resistance. The T682A mutation was negatively correlated with propoxur (r2 = 0.788, P = 0.045 resistance. Knowledge of these mutations may help design strategies for managing pesticide resistance in wild mosquito populations.


    Directory of Open Access Journals (Sweden)



    Full Text Available Susceptibility tests were carried out on Anopheles stephensi with D.D.T(4%, dieldrin (4%, malathion(5%, propoxus (0.1%, primphos-methyl (O.lmg/cm2, lambda-cyhalothrin (0.1%, permethrin (0.25% and deltamethrin (0.025% during 1990-94 in Minab county, soutern Iran, using W.H.O standard method. Results showed that An. stephensi was susceptible to malathion, propoxur, primphos - methyl, lambda- cyhalothrin permethrin and deltamethrin, also LT5O was 5,19.5, less than 1.less than 1,3 and less than 1 minute, respectively. Results indicated that An.stephensi was still resistant to D.D.T and dieldrin but susceptibility level has increased. Mortality rate was 36.1 and 80.6 when the species was exposed to D.D.T and dieldrin impregnated papers for 60 minutes, respectively.

  19. Point mutations associated with organophosphate and carbamate resistance in Chinese strains of Culex pipiens quinquefasciatus (Diptera: Culicidae). (United States)

    Zhao, Minghui; Dong, Yande; Ran, Xin; Wu, Zhiming; Guo, Xiaoxia; Zhang, Yingmei; Xing, Dan; Yan, Ting; Wang, Gang; Zhu, Xiaojuan; Zhang, Hengduan; Li, Chunxiao; Zhao, Tongyan


    Acetylcholinesterase resistance has been well documented in many insects, including several mosquito species. We tested the resistance of five wild, Chinese strains of the mosquito Culex pipiens quinquefasciatus to two kinds of pesticides, dichlorvos and propoxur. An acetylcholinesterase gene (ace1) was cloned and sequenced from a pooled sample of mosquitoes from these five strains and the amino acids of five positions were found to vary (V185M, G247S, A328S, A391T, and T682A). Analysis of the correlation between mutation frequencies and resistance levels (LC50) suggests that two point mutations, G247S (r2 = 0.732, P = 0.065) and A328S (r2 = 0.891, P = 0.016), are associated with resistance to propoxur but not to dichlorvos. Although the V185M mutation was not associated with either dichlorvos or propoxur resistance, its RS genotype frequency was correlated with propoxur resistance (r2 = 0.815, P = 0.036). And the HWE test showed the A328S mutation is linked with V185M, also with G247S mutation. This suggested that these three mutations may contribute synergistically to propoxur resistance. The T682A mutation was negatively correlated with propoxur (r2 = 0.788, P = 0.045) resistance. Knowledge of these mutations may help design strategies for managing pesticide resistance in wild mosquito populations.

  20. Protective effect induced by atropine, carbamates, and 2-pyridine aldoxime methoiodide Artemia salina larvae exposed to fonofos and phosphamidon. (United States)

    Victoria Barahona, M; Sánchez-Fortún, Sebastián


    The acute toxicity of fonofos and phosphamidon on three age classes of Artemia salina was evaluated. An increase in toxicity of these organophosphorous (OP) insecticides was found following longer development of A. salina. The effects of pretreatment with the nonselective muscarinic antagonist atropine, the two reversible acetylcholinesterease inhibitors physostigmine and pyridostigmine, and the cholinesterase-reactivating oxime 2-pyridine aldoxime methoiodide (2-PAM), as individual and combined pretreatments, on OP-induced lethality in 24 h Artemia were also investigated. The lethal action of both OP insecticides was prevented by pretreatment of 24 h Artemia with atropine and 2-PAM, while physostigmine proved ineffective against intoxication with both OP insecticides and pyridostigmine exhibited a low synergic effect. In both cases, the inhibitory effects of combinations of atropine (10(-5)M) plus 2-PAM were greater than those elicited by either drug alone, with the maximum protection afforded being 100%. Combined pretreatment of atropine (10(-5)M) plus physostigmine practically abolished the lethal effects induced by both insecticides. Pretreatment with 2-PAM (10(-6)M) plus physostigmine afforded maximal protection of 100% and 76% on the lethality induced by fonofos and phosphamidon, respectively. The data obtained suggest that the combination of atropine plus 2-PAM or physostigmine and the combined pretreatment of 2-PAM plus physostigmine are effective in the prevention of the lethal effects induced by fonofos and phosphamidon in A. salina larvae.

  1. Biological de-activation of granular formulation of a carbamate insecticide Cartap in water under laboratory conditions


    Khalid Abdullah; Ayat U. Awank; Masood K. Khattak; Sumbal Yasmin


    Cartap 4% (Padan 4G™) at different concentrations was evaluated for its biological deactivation in laboratory-conditions. The insecticide at 1.88 ppm or above concentrations showed significant increase in percent of dead fingerlings up to 46 days insecticide aging as compared to the control, while 0.8 ppm and below proved to be sub-lethal concentrations. The LD50 at 0-day (fresh solution) was 0.997 ppm, which gradually rose to 2.074 ppm up to the day 46. The chemical attained half-life in 44....

  2. Biological de-activation of granular formulation of a carbamate insecticide Cartap in water under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Khalid Abdullah


    Full Text Available Cartap 4% (Padan 4G™ at different concentrations was evaluated for its biological deactivation in laboratory-conditions. The insecticide at 1.88 ppm or above concentrations showed significant increase in percent of dead fingerlings up to 46 days insecticide aging as compared to the control, while 0.8 ppm and below proved to be sub-lethal concentrations. The LD50 at 0-day (fresh solution was 0.997 ppm, which gradually rose to 2.074 ppm up to the day 46. The chemical attained half-life in 44.89 days. Being a very slowly degrading insecticide, Cartap is not desirable in rice-fish culture and a threat to aquatic fauna.

  3. Studies on combined effects of organophosphates or carbamates and morsodren in birds. II. Plasma and cholinesterase in quail fed morsodren and orally dosed with parathion or carbofuran (United States)

    Dieter, M.P.; Ludke, J.L.


    The degree of interaction between mercury and cholinesterase inhibiting pesticides was determined by comparing enzyme responses to sublethal dosages of parathion or carbofuran in quail fed 0.05, 0.5, or 5.0 ppm morsodren for 18 weeks. A statistically significant interaction was defined as greater brain cholinesterase inhibition in morsodren-fed than in clean-fed birds following pesticide dosage. The tissue residues of mercury that accumulated before significant mercury-parathion interactions occurred were higher than levels that might be expected in natural populations, but significant mercury-carbofuran interactions occurred in birds that had only accumulated 1.0 ppm liver mercury. The results indicate that indiscriminate usage of cholinesterase inhibiting pesticides are dangerous, since natural populations of fish-eating birds oftentimes contain this magnitude of mercury.

  4. Experimental Therapeutics Against the Toxic and Lethal Effects Resulting from Acute Exposure to Nerve Agents Without Carbamate Pretreatment in Guinea Pigs (United States)


    induced airway blockage and acute autonomic effects such as mucoid-salivary hypersecretion, reduced airway patency, bradycardia, atrioventricular (AV...acute agent exposure. These included oro- facial movements (indicative of immoderate secretion), mild degree of dystonia/ataxia, and a short period of...intoxicated animals. At 24 hr post-CWA exposure, both the respiratory rate and breathing patterns across Groups 6-10 were comparable to those of

  5. Comparison of two commonly practiced atropinization regimens in acute organophosphorus and carbamate poisoning, doubling doses vs. ad hoc: a prospective observational study. (United States)

    Perera, P M S; Shahmy, S; Gawarammana, I; Dawson, A H


    There is a wide variation and lack of evidence in current recommendations for atropine dosing schedules leading to subsequent variation in clinical practice. Therefore, we sought to examine the safety and effectiveness of a titrated vs. ad hoc atropine treatment regimen in a cohort of patients with acute cholinesterase inhibitor pesticide poisoning. A prospective cohort study was conducted in three district secondary referral hospitals in Sri Lanka using a structured data collection form that collected details of clinical symptoms and outcomes of cholinesterase inhibitor pesticide poisoning, atropine doses, and signs of atropinization. We compared two hospitals that used a titrated dosing protocol based on a structured monitoring sheet for atropine infusion with another hospital using an ad hoc regime. During the study, 272 symptomatic patients with anticholinesterase poisoning requiring atropine were admitted to the three hospitals. Outcomes of death and ventilation were analyzed for all patients, 226 patients were prospectively assessed for atropine toxicity. At baseline, patients in the titrated dose cohort had clinical signs consistent with greater toxicity. This in part may be due to ingestion of more toxic organophosphates. They received less pralidoxime and atropine, and were less likely to develop features of atropine toxicity, such as delirium (1% vs. 17%), hallucinations (1% vs. 35%), or either (1% vs. 35%) and need for patient restraint (3% vs. 48%) compared with the ad hoc dose regime. After adjusting for the pesticides ingested, there was no difference in mortality and ventilatory rates between protocols. Ad hoc high dose atropine regimens are associated with more frequent atropine toxicity without any obvious improvement in patient outcome compared with doses titrated to clinical effect. Atropine doses should be titrated against response and toxicity. Further education and the use of a structured monitoring sheet may assist in more appropriate atropine use in anticholinesterase pesticide poisoning.

  6. Effects of single or repeated administration of a carbamate, propoxur, and an organophosphate, DDVP, on jejunal cholinergic activities and contractile responses in rats. (United States)

    Kobayashi, H; Sato, I; Akatsu, Y; Fujii, S; Suzuki, T; Matsusaka, N; Yuyama, A


    Wistar rats were injected once or repeatedly for 10 days with dichlorvos (DDVP, 5 mg kg-1), propoxur (10 mg kg-1), oxotremorine (0.1 mg kg-1) or atropine (5 mg kg-1). Animals were killed 20 min or 24 h after single or consecutive injections, respectively, for determinations of cholinergic activities and contractile responses to acetylcholine (ACh) of the jejunum. Single treatments: while DDVP and propoxur decreased acetylcholinesterase (AChE) activity, oxotremorine and atropine did not. Although DDVP, propoxur and oxotremorine increased levels of ACh, atropine decreased them. Contractile responses to ACh were enhanced by DDVP and reduced by oxotremorine and atropine. The Bmax value of binding of [3H]quinuclidinyl benzylate (QNB) to muscarinic ACh receptors was decreased by atropine. Consecutive treatments: DDVP and oxotremorine decreased AChE activity markedly and slightly, respectively. Although DDVP and oxotremorine increased levels of ACh, propoxur decreased them. Without affecting the contractile responses, DDVP caused a reduction and propoxur and atropine caused an increase in the Bmax value for binding of [3H]QNB. Both the contractile responses and the value of Bmax for binding of [3H]-QNB were decreased by oxotremorine. In summary, propoxur and DDVP showed similar effects mainly through their anticholinesterase properties in the case of single injection, but DDVP had similar effects to those of oxotremorine and propoxur had similar effects to those of atropine in the case of repeated injection.

  7. 3-Oxoisoxazole-2(3H)-carboxamides and isoxazol-3-yl carbamates: Resistance-breaking acetylcholinesterase inhibitors targeting the malaria mosquito, Anopheles gambiae (United States)

    Verma, Astha; Wong, Dawn M.; Islam, Rafique; Tong, Fan; Ghavami, Maryam; Mutunga, James M.; Slebodnick, Carla; Li, Jianyong; Viayna, Elisabet; Lam, Polo C.-H.; Totrov, Maxim M.; Bloomquist, Jeffrey R.; Carlier, Paul R.


    To identify potential selective and resistance-breaking mosquitocides against the African malaria vector Anopheles gambiae, we investigated the acetylcholinesterase (AChE) inhibitory and mosquitocidal properties of isoxazol-3-yl dimethylcarbamates (15), and the corresponding 3-oxoisoxazole-2(3H)-dimethylcarboxamide isomers (14). In both series, compounds were found with excellent contact toxicity to wild-type susceptible (G3) strain and multiply resistant (Akron) strain mosquitoes that carry the G119S resistance mutation of AChE. Compounds possessing good to excellent toxicity to Akron strain mosquitoes inhibit the G119S mutant of An. gambiae AChE (AgAChE) with ki values at least 10- to 600-fold higher than that of propoxur, a compound that does not kill Akron mosquitoes at the highest concentration tested. On average, inactivation of WT AgAChE by dimethylcarboxamides 14 was 10-20 fold faster than that of the corresponding isoxazol-3-yl dimethylcarbamates 15. X-ray crystallography of dimethylcarboxamide 14d provided insight into that reactivity, a finding that may explain the inhibitory power of structurally-related inhibitors of hormone-sensitive lipase. Finally, human/An. gambiae AChE inhibition selectivities of these compounds were low, suggesting the need for additional structural modification. PMID:25684426

  8. Novel urea-linked cinchona-calixarene hybrid-type receptors for efficient chromatographic enantiomer separation of carbamate-protected cyclic amino acids. (United States)

    Krawinkler, Karl Heinz; Maier, Norbert M; Sajovic, Elisabeth; Lindner, Wolfgang


    Two novel diastereomeric cinchona-calixarene hybrid-type receptors (SOs) were synthesized by inter-linking 9-amino(9-deoxy)-quinine (AQN)/9-amino(9-deoxy)-epiquinine (eAQN) and a calix[4]arene scaffold via an urea functional unit. Silica-supported chiral stationary phases (CSPs) derived from these SOs revealed, for N-protected amino acids, complementary chiral recognition profiles in terms of elution order and substrate specificity. The AQN-derived CSP showed narrow-scoped enantioselectivity for open-chained amino acids bearing pi-acidic aromatic protecting groups, preferentially binding the (S)-enantiomers. In contrast, the eAQN congener exhibited broad chiral recognition capacity for open-chained as well as cyclic amino acids, and preferential binding of the (R)-enantiomers. Exceedingly strong retention due to nonenantioselective hydrophobic analyte-calixarene interactions observed with hydro-organic mobile phases could be largely suppressed with organic mobile phases containing small amounts of acetic acid as acidic modifier. With the eAQN-calixarene hybrid-type CSP particularly high levels of enantioselectivity could be achieved for tert-butoxycarbonyl (Boc)-, benzyloxycarbonyl (Z)- and fluorenylmethoxycarbonyl (Fmoc)-protected cyclic amino acids using chloroform as mobile phase, e.g. an enantioselectivty factor alpha >5.0 for Boc-proline. Increasing amounts of acetic acid compromised enantioselectivity, indicating the crucial contributions of hydrogen bonding to chiral recognition. Comparison of the performance characteristics of the urea-linked eAQN-calixarene hybrid-type CSP with those of structurally closely related mutants provided evidence for the active involvement of the urea and calixarene units in the chiral recognition process. The urea linker motif was shown to contribute to analyte binding via multiple hydrogen bonding interactions, while the calixarene module is believed to support stereodiscrimination by enhancing the shape complementarity of the SO binding site.

  9. Crystal structure of ethyl N-(1,5-dimethyl-3-oxo-2-phenyl-2,3-di­hydro-1H-pyrazol-4-yl)carbamate (United States)

    Danish, Muhammad; Tahir, Muhammad Nawaz; Anwar, Uzma; Raza, Muhammad Asam


    In the title compound, C14H17N3O3, the dihedral angle between the benzene ring and the five-membered di­hydro­pyrazole ring is 52.26 (9)°. The ethyl ester group is approximately planar (r.m.s. deviation 0.0568 Å) and subtends an angle 67.73 (8)° to the pyrazole ring. In the crystal, molecules are linked by pairs of N—H⋯O hydrogen bonds, forming inversion dimers with an R 2 2(10) ring motif. Weaker C—H⋯O contacts link these dimers into a three-dimensional network of mol­ecules stacked along the a-axis direction. Offset π–π stacking inter­actions between the benzene rings [centroid-to-centroid distance = 3.8832 (12) Å] further stabilize the crystal packing. PMID:26029449

  10. Identification and quantification of carbamate pesticides in dried lime tree flowers by means of excitation-emission molecular fluorescence and parallel factor analysis when quenching effect exists. (United States)

    Rubio, L; Ortiz, M C; Sarabia, L A


    A non-separative, fast and inexpensive spectrofluorimetric method based on the second order calibration of excitation-emission fluorescence matrices (EEMs) was proposed for the determination of carbaryl, carbendazim and 1-naphthol in dried lime tree flowers. The trilinearity property of three-way data was used to handle the intrinsic fluorescence of lime flowers and the difference in the fluorescence intensity of each analyte. It also made possible to identify unequivocally each analyte. Trilinearity of the data tensor guarantees the uniqueness of the solution obtained through parallel factor analysis (PARAFAC), so the factors of the decomposition match up with the analytes. In addition, an experimental procedure was proposed to identify, with three-way data, the quenching effect produced by the fluorophores of the lime flowers. This procedure also enabled the selection of the adequate dilution of the lime flowers extract to minimize the quenching effect so the three analytes can be quantified. Finally, the analytes were determined using the standard addition method for a calibration whose standards were chosen with a D-optimal design. The three analytes were unequivocally identified by the correlation between the pure spectra and the PARAFAC excitation and emission spectral loadings. The trueness was established by the accuracy line "calculated concentration versus added concentration" in all cases. Better decision limit values (CCα), in x0=0 with the probability of false positive fixed at 0.05, were obtained for the calibration performed in pure solvent: 2.97 μg L(-1) for 1-naphthol, 3.74 μg L(-1) for carbaryl and 23.25 μg L(-1) for carbendazim. The CCα values for the second calibration carried out in matrix were 1.61, 4.34 and 51.75 μg L(-1) respectively; while the values obtained considering only the pure samples as calibration set were: 2.65, 8.61 and 28.7 μg L(-1), respectively.

  11. Genotoxic effects of the carbamate insecticide Pirimor-50® in Vicia faba root tip meristems and human lymphocyte culture after direct application and treatment with its metabolic extracts. (United States)

    Valencia-Quintana, Rafael; Gómez-Arroyo, Sandra; Sánchez-Alarcón, Juana; Milić, Mirta; Olivares, José Luis Gómez; Waliszewski, Stefan M; Cortés-Eslava, Josefina; Villalobos-Pietrini, Rafael; Calderón-Segura, María Elena


    The aim of the study was to evaluate genotoxic effects of Pirimor-50®, a pirimicarb-based formulation (50 % active ingredient), in human lymphocyte cultures and Vicia faba root meristems. Furthermore, the objective was to examine a combined influence of insecticide treatment with mammalian microsomal S9 and vegetal S10 metabolic fractions or S10 mix metabolic transformation extracts (after Vicia faba primary roots treatment with Pirimor-50®). We used sister chromatid exchange assay-SCE and measured cell cycle progression and proliferation (proportion of M1-M3 metaphases and replication index ratio-RI). Two processes were used for plant promutagen activation: in vivo activation-Pirimor-50® was applied for 4 h to the plant and then S10 mix was added to lymphocytes; and, in vitro activation-lymphocytes were treated with Pirimor-50® and S10 or S9 for 2 h. Direct treatment induced significantly higher SCE frequencies in meristems at 0.01 mg mL-1. In lymphocytes, significantly higher SCE was at 1 mg mL-1 with decrease in RI and M1-M3 metaphase proportions at 0.5 mg mL-1 and cell division stop at 2.5 mg mL1. S10 mix lymphocyte treatment showed significantly elevated SCE values at 2-2.5 mg mL-1, with cell death at 3 mg mL-1. Lymphocyte treatment with Pirimor-50® together with S9 or S10 showed slightly elevated SCE frequency but had a significant influence on RI decrease, with lowest values in S9 treatment. Since no data are available on the genotoxicity of Pirimor-50®, this study is one of the first to evaluate and compare its direct effect in two bioassays, animal and vegetal, and also the effect of plant and animal metabolism on its genotoxic potential.

  12. Synthesis and Crystal Structure of Benzyl [(1S-1-(5-amino-1,3,4-oxadiazol-2-yl-2-phenylethyl]carbamate

    Directory of Open Access Journals (Sweden)

    Reik Löser


    Full Text Available The conversion of Z-phenylalanine hydrazide with cyanogen bromide resulted in the formation of the corresponding 2-amino-1,3,4-oxadiazole by spontaneous cyclization of the intermediary cyanohydrazide. The molecular structure of the product was confirmed by single crystal X-ray diffraction. Crystals of the title compound where obtained from a saturated solution in a mixture of petroleum ether and ethyl acetate and belong to the monoclinic space group P21 with unit cell parameters a = 9.8152(2 Å, b = 9.6305(2 Å, c = 9.8465(2 Å, β = 116.785(1°. The asymmetric unit contains one molecule.

  13. 氨汽提法尿素装置中压甲铵冷凝器防结垢工艺优化%Process Optimization for Anti-Fouling of Carbamate Condenser in Urea Plant withAmmonia Stripping Method

    Institute of Scientific and Technical Information of China (English)

    余志文; 程忠振



  14. Mechanistic Insights into an Unexpected Carbon DioxideInsertion Reaction through the Crystal Structures of CarbamicDiphenylthiophosphinic Anhydride and 1-[( 4-Nitrophenyl )-sulfonyl ]-trans-2,5-pyrrolidinedicarboxylic Acid Methyl Ester

    Institute of Scientific and Technical Information of China (English)

    SHI, Min; SHEN, Yu-Mei; JIANG, Jian-Kang


    The crystal structures of an unexpected carbon dioxide inserted carbamicdiphenylthiophosphinic anhydride and 1-[(4-nitrophenyl) sulfonyl]- trans-2, 5-pyrrolidinedicarboxylic acid methyl ester were determined by X-ray analysis. They crystallized in the space group P21(#4) with α=0.9550(2), b=0.9401(4), c= 1.2880(2) nm, β= 107.74°, V=1.1013(5) nm3, D calcd = 1.349 g/cm3, Z = 2 and P212121 ( # 19)with α= 1.4666(2), b = 0.7195(2), c = 1.6339(2) nm, V= 1.7240(7) nm3, Dcalcd= 1.434 g/cm3, Z=4, respectively.Through the investigation of these two crystal structures, the mechanistic insights into this unexpected carbon dioxide insertion in the reaction of trans-2,5-disubstituted pyrrolidine with diphenylthiophosphoryl chloride in the presence of potassium carbonate were disclosed.

  15. Evaluation of a new carbamate insecticide Shachongwei on three lepidopteran pests%杀虫威对棉铃虫、烟青虫、菜青虫的防治效果

    Institute of Scientific and Technical Information of China (English)

    谢宝瑜; 李典谟; 秦小薇; 任连奎; 曾益良; 高曰亭; 韩桂仲; 刘顺通


    田间试验表明,新氨基甲酸酯杀虫剂杀虫威对鳞翅目害虫棉铃虫、菜青虫、烟青虫防治效果优良.杀虫威20%EC在河南防治2代棉铃虫使用剂量10 g (a.i.)/667 m2药后2~7 d,校正防效为90.65%~97.72%,在山东药后3~5 d,防效为85.17%~91.23%,7.5 g (a.i.)/667 m2相应药效两地分别为88.41%~95.27%和81.40%~85.61%;防治3代棉铃虫使用剂量20 g (a.i.)/667 m2药后2~5 d,防效两地分别为83.93%~86.15%和85.53%~88.29%,15 g (a.i.)/667 m2相应药效分别为77.66%~80.23%和78.50%~83.75%.防治烟青虫使用剂量10 g (a.i.)/667 m2药后3~7 d校正防效为85.57%~88.29%,7.5 g (a.i.)/667 m2相应药效为81.51%~86.11%.防治菜青虫使用剂量7.5~10 g (a.i.)/667 m2药后3~7 d防效为87.50%~96.11%.

  16. Efficacy of several carbamate inseticides on Liriomyza sativae%几种氨基甲酸酯类杀虫剂对美洲斑潜蝇的防治效果

    Institute of Scientific and Technical Information of China (English)

    曾益良; 王大生; 秦小薇; 任连奎; 王同顺; 钟读华; 刘红梅; 王宝瑛; 王忠泽


    在山东青州以茄子为试验寄主,丁硫克百威10 g(a.i.)/667 m2、灭蚜威15 g(a.i.)/667 m2、速灭威12.5 g(a.i.)/667 m2、扑蚜威12.5 g(a.i.)/667 m2 对美洲斑潜蝇幼虫药后3~7 d校正防效分别为91.13% ~91.14%,89.66%~91.66%,89.29%~91.36%,87.82%~88.83%,均具有良好的速效和持效性。在山东青州以西葫芦为试验寄主,间乙威12.5 g(a.i.)/667m2、灭除威15 g(a.i.)/667m2、灭杀威15 g(a.i.)/667 m2、间异丙威15 g(a.i.)/667 m2对美洲斑潜蝇幼虫药后3~7 d校正防效均在80%左右,防效一般。在北京海淀以黄瓜为试验寄主,灭蚜威WP 20 g(a.i.)/667 m2对美洲斑潜蝇幼虫药后3~11d校正防效为84.93%~85.47%。以不同寄主,杀虫威10 g(a.i.)/667 m2对美洲斑潜蝇幼虫药后3~7 d校正防效为85%以上。丁硫克百威、速灭威、灭蚜威、扑蚜威、杀虫威均可以作为防治美洲斑潜蝇的有效药剂。


    Institute of Scientific and Technical Information of China (English)

    洪浩; 李静; 高丽雅; 王海鸥; 王哲凯; 岳红杉; 李芳; 王延吉


    利用等体积浸渍法制备了用于合成苯氨基甲酸甲酯的负载型ZnO-TiO2催化剂,考察了载体对负载型ZnO-TiO2催化剂催化性能的影响.实验结果表明:以SiO2为载体时,ZnO-TiO2/SiO2催化剂上MPC的选择性明显高于以HZSM-5和γ-Al2O3为载体制备的催化剂,当n(苯胺)∶n(DMC)=1∶20,m(催化剂)∶m(DMC) =0.013,反应温度为443 K,反应时间为7h时,其对苯胺的转化率为49.9%,MPC的选择性为52.3%;和ZnO-TiO2催化剂相比,ZnO-TiO2/SiO2催化剂对于MPC的选择性也有所提高.采用NH3-TPD、Py-IR、XPS对负载型ZnO-TiO2进行了表征,结果表明负载型ZnO-TiO2催化剂其表面酸强度弱的L酸中心有利于MPC合成.

  18. 40 CFR 180.254 - Carbofuran; tolerances for residues. (United States)


    ... Parts per million (ppm) Expiration/Revocation date Alfalfa, forage (of which no more than 5 ppm are carbamates) 10 12/31/09 Alfalfa, hay (of which no more than 20 ppm are carbamates) 40 12/31/09 Banana 0.1 12... which no more than 1.0 ppm is carbamates) 5.0 12/31/09 Beet, sugar, roots 0.1 12/31/09 Beet, sugar,...

  19. Synthesis of new 4,6-disubstituted-1,3-oxazinan-2-one analogues

    Indian Academy of Sciences (India)

    Arun Jyoti Borah; Prodeep Phukan


    1,3-Oxazinan-2-one analogues are important heterocyclic compounds having significant biological activities. This study reports the synthesis of eight new 4,6-disubstituted -1,3-oxazinan-2-one analogues from corresponding homoallylic carbamates. Homoallylic carbamates were synthesized via a three-component reaction of aldehyde, allyltrimethylsilane and benzyl carbamate in presence of iodine as catalyst. In the next step, homoallylic carbamates were subjected to Sharpless dihydroxylation (racemic) to produce 3,4-dihydroxybutylcarbamate derivatives. This product was then treated with NaH in tetrahydrofuran (THF) to produce the desired 6-(hydroxymethyl)-1,3-oxazinan-2-one in high yield.

  20. Low Catalyst Loadings in Olefin Metathesis: Synthesis of Nitrogen Heterocycles by Ring Closing Metathesis (United States)

    Kuhn, Kevin M.; Champagne, Timothy M.; Hong, Soon Hyeok; Wei, Wen-Hao; Nickel, Andrew; Lee, Choon Woo; Virgil, Scott C.; Grubbs, Robert H.; Pederson, Richard L.


    (eq 1) A series of ruthenium catalysts have been screened under ring closing metathesis (RCM) conditions to produce five-, six-, and seven-membered carbamate-protected cyclic amines. Many of these catalysts demonstrated excellent RCM activity and yields with as low as 500 ppm catalyst loadings. RCM of the five-membered carbamate-series could be run neat, the six-membered carbamate-series could be run at 1.0 M concentrations and the seven-membered carbamate-series worked best at 0.2 M to 0.05 M concentrations. PMID:20141172

  1. Low catalyst loadings in olefin metathesis: synthesis of nitrogen heterocycles by ring-closing metathesis. (United States)

    Kuhn, Kevin M; Champagne, Timothy M; Hong, Soon Hyeok; Wei, Wen-Hao; Nickel, Andrew; Lee, Choon Woo; Virgil, Scott C; Grubbs, Robert H; Pederson, Richard L


    A series of ruthenium catalysts have been screened under ring-closing metathesis (RCM) conditions to produce five-, six-, and seven-membered carbamate-protected cyclic amines. Many of these catalysts demonstrated excellent RCM activity and yields with as low as 500 ppm catalyst loadings. RCM of the five-membered carbamate series could be run neat, the six-membered carbamate series could be run at 1.0 M, and the seven-membered carbamate series worked best at 0.2-0.05 M.

  2. 76 FR 2618 - Minnesota: Final Authorization of State Hazardous Waste Management Program Revision (United States)


    ...; Land Disposal Restrictions 63 FR 46332. Effective June 22, Phase IV Zinc Micronutrient 2009..., Zinc Micronutrient 7045.1390; Effective Fertilizers, Carbamate June 22, 2009. Treatment Standards,...

  3. Improving the Capture of Co2 by Substituted Monoethanolamines: Electronic Effects of Fluorine and Methyl Substituents

    NARCIS (Netherlands)

    Gangarapu, S.; Marcelis, A.T.M.; Zuilhof, H.


    The influence of electronic and steric effects on the reaction between CO(2) and monoethanolamine (MEA) absorbents is investigated using computational methods. The pK(a) of the alkanolamine, the reaction enthalpy for carbamate formation, and the hydrolytic carbamate stability are important factors f

  4. 农药克百威和丁硫克百威的质谱分析

    Institute of Scientific and Technical Information of China (English)



    In this paper carbamate pesticide Carbofuran and Carbosulfan are analyzed by MS The showed signals of (M+1) is stronger with CI+ source than (M) with EI source. More MS information can be acquired by CI+ and EI interchange use The else carbamate pesticide such as isoprocarb and metolcarb can be analyzed with same method The results are good.

  5. Mechanisms of CO2 Capture into Monoethanolamine Solution with Different CO2 Loading during the Absorption/Desorption Processes. (United States)

    Lv, Bihong; Guo, Bingsong; Zhou, Zuoming; Jing, Guohua


    Though the mechanism of MEA-CO2 system has been widely studied, there is few literature on the detailed mechanism of CO2 capture into MEA solution with different CO2 loading during absorption/desorption processes. To get a clear picture of the process mechanism, (13)C nuclear magnetic resonance (NMR) was used to analyze the reaction intermediates under different CO2 loadings and detailed mechanism on CO2 absorption and desorption in MEA was evaluated in this work. The results demonstrated that the CO2 absorption in MEA started with the formation of carbamate according to the zwitterion mechanism, followed by the hydration of CO2 to form HCO3(-)/CO3(2-), and accompanied by the hydrolysis of carbamate. It is interesting to find that the existence of carbamate will be influenced by CO2 loading and that it is rather unstable at high CO2 loading. At low CO2 loading, carbamate is formed fast by the reaction between CO2 and MEA. At high CO2 loading, it is formed by the reaction of CO3(-)/CO3(2-) with MEA, and the formed carbamate can be easily hydrolyzed by H(+). Moreover, CO2 desorption from the CO2-saturated MEA solution was proved to be a reverse process of absorption. Initially, some HCO3(-) were heated to release CO2 and other HCO3(-) were reacted with carbamic acid (MEAH(+)) to form carbamate, and the carbamate was then decomposed to MEA and CO2.

  6. Different aspects of S-carvone A natural potato sprout growth inhibitor.

    NARCIS (Netherlands)

    Oosterhaven, J.


    After harvest, potato tubers are usually stored at a temperature of 6-8°C in combination with the application of a synthetic sprout inhibitor. Frequently used sprout inhibitors are isopropyl N-phenyl-carbamate (propham or IPC), isopropyl N-(3-chlorophenyl)carbamate (chlorpropham or CIPC) or a combin

  7. Carbon dioxide chemistry on the surface of Titan (United States)

    Hodyss, Robert; Piao, Sophie; Malaska, Michael; Cable, Morgan


    Titan possesses many of the basic elements of habitability, including a rich organic chemistry. However, the thick atmosphere of Titan shields the surface from radiation, which makes the incorporation of oxygen into organic compounds difficult, due to a reducing environment and low temperatures that slow chemical reactions. These obstacles may be overcome by impacts or cryovolcanic heating of ice, which would mix organics with liquid water and allow chemical reactions that can incorporate oxygen. However, reactions involving oxygen can occur on Titan without invoking such unusual conditions. We show that the reaction of carbon dioxide with amines can lead to oxygenated organics at Titan's surface without the need for external energy input, via the carbamation reaction: R-NH2 + CO2 → R-NH-COOH. Using a combination of micro-Raman spectroscopy and UHV FTIR spectroscopy, we examine the reaction products and kinetics of the carbamation reaction for a variety of primary and secondary amines. We have observed carbamic acid formation in mixtures of methylamine, ethylamine and dibutylamine with CO2 at cryogenic temperatures. This indicates that both primary and secondary amines can undergo carbamation at low temperatures. Reaction was observed with methylamine as low as 40 K, and with ethylamine at 100 K, demonstrating that carbamation is fast at Titan surface temperatures. We will present data on the kinetics of the carbamation reaction for a variety of amines, as well as estimates of the quantity of carbamic acids that may be produced on Titan's surface and in the atmosphere.

  8. Synthesis of N-methyl substituted phenyl carbamates and their activities to housefly%N-甲基取代苯基氨基甲酸酯的系列合成及其对家蝇的生物活性

    Institute of Scientific and Technical Information of China (English)

    严炳丽; 曾益良; 任连奎; 王同顺; 解立华


    利用酰氯水相简易工艺合成了52个N-甲基取代苯基氨基甲酸酯类化合物,并测定了它们对家蝇Musca domestica的室内毒力.结果表明:烷基单取代化合物中,间位取代物的活性大于邻、对位;单卤素取代物中,邻位取代活性大于间位和对位,邻溴代物大于邻氯代物;对位硫甲基和邻位硫乙基取代物的活性均较高.对于烷基间位苯环取代化合物,在一定限度内随烷基分子量增大,化合物对家蝇的毒力增高,其次序为异丙基>乙基>甲基>未取代基.

  9. QuEChERS-超高效液相色谱-串联质谱法测定荨麻提取物中17种氨基甲酸酯类农药残留量%Determination of 17 carbamate pesticide residues in nettle extract using QuEChERS coupled with ultra performance liquid chromatography-tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    何强; 张璐; 张亚莉; 孔祥虹; 刘开; 邹阳; 付骋宇; 李莹


    采用QuEChERS-起高液相色谱-串联质谱技术,建立了荨麻提取物中17种常见的氨基甲酸酯类农药残留量的检测方法.样品用含1%甲酸的乙腈提取,QuEChERS法净化,电喷雾正离子(ESI+)模式电离,多反应监测模式检测,基质匹配标准曲线法定量.17种氨基甲酸酯农药在2.5~ 50 μg/L线性关系良好,相关系数均大于0.9920,加标浓度为10,20,50μg/kg,平均回收率在65.3%~119.2%,相对标准偏差(RSD)均低于11%,检出限在0.12 ~ 1.7 μg/kg.方法适用于荨麻等植物提取物中氨基甲酸酯类农药残留量的测定.


    Directory of Open Access Journals (Sweden)

    Antônio Lopes da Silva


    Full Text Available

    The tomato leafminer (Scrobipalpuloides absoluta, a common pest of tomato plants, is known in many regions in Brazil. In order to determine the efficiency of new insecticide alanycarb, to control the tomato leafminer a field experiment was carried out in Goiânia, Goiás, Brazil. The treatments and dosage of the insecticides per hectare were: alanycarb 300: 1.0, 1.5 and 2.0 l; cartap 500 BR: 2.0 kg; abamectin 18 CE: 1.0 1 plus an untreated check. The results obtained in this experiment showed that all insecticides were efficient in controlling the tomato leafminer until 8 days after treatment application and they were able to increase productivity.

    KEY-WORDS: Scrobipalpuloides absoluta; tomato leafminer; chemical control.

    O experimento foi realizado na área de horticultura da Escola de Agronomia da Universidade Federal de Goiás, visando ao controle químico da traça do tomateiro (Scrobipalpuloides absoluta Meyric, 1917, no período de setembro a dezembro de 1995, para avaliar a eficiência do inseticida Onic 300 (Alanycarb nas dosagens de 1,0, 1,5 e 2,0 litros do produto formulado por ha, comparando-o com Cartap 500 BR (Cartap na dosagem de 2,4 kg/ha, Vertimec 18 CE (Abamectin na dosagem de 1,0 l/ha misturado a um óleo mineral e uma testemunha. Pelos resultados obtidos concluiu-se que todos os inseticidas utilizados controlaram eficientemente a traça em tomateiro até 8 dias após aplicação e que todos os tratamentos promoveram aumento de produtividade.

    PALAVRAS-CHAVE: Traça; Scrobipalpuloides absoluta; controle químico; tomateiro.

  11. Simultaneous determination of carbamate pesticides in chestnut and pine nut by high performance liquid chromatography with post-column fluorescence derivatization%高效液相色谱柱后衍生法测定栗子和松籽中氨基甲酸酯娄农药残留量

    Institute of Scientific and Technical Information of China (English)

    杨民乐; 薛园园; 宋欢; 林勤保



  12. Thermally activated, single component epoxy systems

    KAUST Repository

    Unruh, David A.


    A single component epoxy system in which the resin and hardener components found in many two-component epoxies are combined onto the same molecule is described. The single molecule precursor to the epoxy resin contains both multiple epoxide moieties and a diamine held latent by thermally degradable carbamate linkages. These bis-carbamate "single molecule epoxies" have an essentially infinite shelf life and access a significant range in curing temperatures related to the structure of the carbamate linkages used. © 2011 American Chemical Society.

  13. Carbofuran-Induced Acute Pancreatitis

    Directory of Open Access Journals (Sweden)

    Rizos E


    Full Text Available CONTEXT: Carbamate insecticides are widely used in commercial agriculture and home gardening. A serious side effect of organophosphate and carbamate intoxication is the development of acute pancreatitis. CASE REPORT: A 36-year-old Caucasian woman was admitted to our hospital with cholinergic crisis and pancreatitis soon after the ingestion of a carbamate insecticide (carbofuran. An abdominal CT scan disclosed pancreatic necrosis with intrapancreatic fluid collection, consistent with the development of a pancreatic pseudocyst in a subsequent CT scan. No predisposing factor for pancreatitis was evident. Pseudocholinesterase levels returned to normal 7 days later and the patient was discharged in good physical condition one month after admission. DISCUSSION: Although acute pancreatitis is not infrequent after organophosphate intoxication, it is quite rare after carbamate ingestion and has not been previously reported after carbofuran intoxication.

  14. The activity of non-specific esterase in the thyroid epithelial cells of the guinea pig as influenced by various inhibitors and activators. A histochemical study

    DEFF Research Database (Denmark)

    Kirkeby, S


    The action of various inhibitors and activators upon esterase activity in the thyroid epithelial cells is demonstrated. The agents used were triorthocresylphosphate (TOCP), parachloromercuribenzoate (PCMB), Arsanillic acid, p-nitrophenyl dimethyl carbamate and bis p-nitrophenyl phosphate. TOCP wa...

  15. 76 FR 34978 - Petition Supplement Requesting Cancellation of Propoxur Pet Collar Uses; Notice of Availability (United States)


    ... AGENCY Petition Supplement Requesting Cancellation of Propoxur Pet Collar Uses; Notice of Availability... pet collar uses for the pesticide propoxur. The petitioner, NRDC, initially requested these...-methyl Carbamate (NMC) Cumulative Risk Assessment (CRA) underestimate exposure to propoxur from...

  16. Drug: D07613 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D07613 Drug Carbaryl (BAN); Carbaril; Flea and tick powder [veterinary] (TN) C12H11...NO2 201.079 201.2212 D07613.gif Insecticide Same as: C07491 carbamate insecticide cholinesterase inhibitor veterinary

  17. Synthesis and herbicidal activities of pyridyl sulfonylureas:More convenient preparation process of phenyl pyrimidylcarbamates

    Institute of Scientific and Technical Information of China (English)

    Ning Ma; Zhi Jin Fan; Bao Lei Wang; Yong Hong Li; Zheng Ming Li


    Four 4-monosubstituted pyrimidine pyridyl sulfonylureas were synthesized from pyridinesulfonamide and phenyl pyrimidyl-carbamate and screened for herbicidal activities.We also reported a convenient preparation process of phenyl pyrimidylcarbamates from pyrimidineamine and phenyl chloroformate.

  18. Granular Nematicides as Adjuncts to Fumigants for Control of Cotton Root-knot Nematodes. (United States)

    Jorgenson, E C


    Growth and yield of cotton were best with combinations of fumigants and organophosphate and carbamate nematicides. Organophosphates or carbamates used alone did not give season-long control of root-knot nematodes. Long-term control was poor because the temporary sublethal effects of these materials diminished soon enough lhat the nematodes could reproduce. The nematodes survived the treatments and a year of nonhost culture, and damaged a susceptible host crop 2 years after treatment. No such damage occurred in plots treated with fumigant, fumigant plus organophosphate, or fumigant plus carbamate. Treatment of seed and treatment of cotton, either in furrow at planting or sidedressing at midseason, with organophosphate and carbamate nematicides resulted in little or no yield increase, because nematode control was only minimal and temporary; or in a yield decrease, because the toxicity of the materials was manifested when nematode populations were low.

  19. Effects of Selected Insecticides and Nematicides on the In Vitro Development of the Entomogenous Nematode Neoaplectana carpocapsae. (United States)

    Hara, A H; Kaya, H K


    The effects of organophosphates (mevinphos, phenamiphos, trichlorfon), carbamates (carbofuran, methomyl, oxamyl), a formamidine (chlordimeform), a synthetic pyrethroid (fenvalerate), a chlorinated hydrocarbon (methoxychlor). and an insect growth regulator (diflubenzuron) on in vitro development and reproduction of Neoaplectana carflocapsae were tested by incorporating each chemical into a nematode rearing medium. Organophosphates and carbamates adversely affected development and reproduction at concentrations >/= 0.1 mg/ml. Phenamiphos was the most toxic, with no nematode reproduction at 0.01 mg/ml. Inoculated infective juveniles developed to adults with some of the organophosphates and carbamates, but limited or no reproduction occurred. Chlordimeform inhibited development at 1.0 mg/ml, while diflubenzuron, fenvalerate, and methoxychlor did not significantly (P > 0.05) reduced reproduction at 1.0 mg/ml. The organophosphate and carbamate nematicides in use for control of plant-parasitic nematodes may be toxic to N. carpocapsae in the soil.

  20. Acquisition of HPLC-Mass Spectrometer (United States)


    Replacing this large bulky tert-butyl carbamate with a thinner less sterically encumbering protecting group such as a methyl carbamate may eliminate the...This instrument has been an asset in organic synthesis and natural product isolation and teaching in organic, biochemistry, and instrumental analysis...isolation and teaching in organic, biochemistry, and instrumental analysis classes. Over the last year thie mass spectrometer has directly influenced the

  1. Methomyl-Induced Severe Acute Pancreatitis: Possible Etiological Association


    Ioannides M; Christodoulides P; Symeonides M; Vounou E; Tsikkos S; Achillews G; Koukouvas M; Makrides C


    CONTEXT: N-methyl carbamate insecticides are widely used in homes, gardens and agriculture. They share the capacity to inhibit cholinesterase enzymes with organophosphates and therefore share similar symptomatology during acute and chronic exposures. One of the serious effects of organophosphate and carbamate intoxication is the development of acute pancreatitis and subsequent intrapancreatic fluid formation. CASE REPORT: An 18-year old Caucasian man was admitted to our Intensive Care Unit wi...

  2. Snapshot of a phosphorylated substrate intermediate by kinetic crystallography


    Käck, Helena; Gibson, Katharine J.; Lindqvist, Ylva; Schneider, Gunter


    The ATP-dependent enzyme dethiobiotin synthetase from Escherichia coli catalyses the formation of dethiobiotin from CO2 and 7,8-diaminopelargonic acid. The reaction is initiated by the formation of a carbamate and proceeds through a phosphorylated intermediate, a mixed carbamic phosphoric anhydride. Here, we report the crystal structures at 1.9- and 1.6-Å resolution, respectively, of the enzyme–MgATP–diaminopelargonic acid and enzyme–MgADP–carbamic–phosphoric acid anhydride complexes, observe...

  3. Green nanotechnology: a short cut to beneficiation of natural fibers. (United States)

    Fahmy, Tamer Y A; Mobarak, Fardous


    For the first time worldwide, it is shown that our novel nanocomposite produced from natural fibers vaccinated with glucose--by fully green nanotechnology--possesses surprising reactivity towards urea. Magic super absorbent carbamated nanocomposite cotton fabrics having remarkable distinguished properties were obtained in few minutes. It is well established that carbamates possess antibacterial effects. The produced magic nanocomposite fabrics, we discovered for the first time worldwide, find their use as woven or nonwoven hygienic pads, bandages or paper nanocomposites.

  4. A Mechanism-based 3D-QSAR Approach for Classification ... (United States)

    Organophosphate (OP) and carbamate esters can inhibit acetylcholinesterase (AChE) by binding covalently to a serine residue in the enzyme active site, and their inhibitory potency depends largely on affinity for the enzyme and the reactivity of the ester. Despite this understanding, there has been no mechanism-based in silico approach for classification and prediction of the inhibitory potency of ether OPs or carbamates. This prompted us to develop a three dimensional prediction framework for OPs, carbamates, and their analogs. Inhibitory structures of a compound that can form the covalent bond were identified through analysis of docked conformations of the compound and its metabolites. Inhibitory potencies of the selected structures were then predicted using a previously developed three dimensional quantitative structure-active relationship. This approach was validated with a large number of structurally diverse OP and carbamate compounds encompassing widely used insecticides and structural analogs including OP flame retardants and thio- and dithiocarbamate pesticides. The modeling revealed that: (1) in addition to classical OP metabolic activation, the toxicity of carbamate compounds can be dependent on biotransformation, (2) OP and carbamate analogs such as OP flame retardants and thiocarbamate herbicides can act as AChEI, (3) hydrogen bonds at the oxyanion hole is critical for AChE inhibition through the covalent bond, and (4) π–π interaction with Trp86

  5. Toward the understanding of chemical absorption processes for post-combustion capture of carbon dioxide: electronic and steric considerations from the kinetics of reactions of CO2(aq) with sterically hindered amines. (United States)

    Conway, William; Wang, Xiaoguang; Fernandes, Debra; Burns, Robert; Lawrance, Geoffrey; Puxty, Graeme; Maeder, Marcel


    The present study reports (a) the determination of both the kinetic rate constants and equilibrium constants for the reaction of CO(2)(aq) with sterically hindered amines and (b) an attempt to elucidate a fundamental chemical understanding of the relationship between the amine structure and chemical properties of the amine that are relevant for postcombustion capture of CO(2) (PCC) applications. The reactions of CO(2)(aq) with a series of linear and methyl substituted primary amines and alkanolamines have been investigated using stopped-flow spectrophotometry and (1)H NMR measurements at 25.0 °C. The specific mechanism of absorption for each of the amines, that is CO(2) hydration and/or carbamate formation, is examined and, based on the mechanism, the kinetic and equilibrium constants for the formation of carbamic acid/carbamates, including protonation constants of the carbamate, are reported for amines that follow this pathway. A Brønsted correlation relating the kinetic rate constants and equilibrium constants for the formation of carbamic acid/carbamates with the protonation constant of the amine is reported. Such a relationship facilitates an understanding of the effects of steric and electronic properties of the amine toward its reactivity with CO(2). Further, such relationships can be used to guide the design of new amines with improved properties relevant to PCC applications.

  6. Effects of aldicarb and propoxur on cytotoxicity and lipid peroxidation in CHO-K1 cells. (United States)

    Maran, E; Fernández-Franzón, M; Font, G; Ruiz, M J


    Cytotoxic effects of aldicarb, its sulfone and sulfoxide, and propoxur, lipid peroxidation and antioxidant parameters in Chinese Hamster Ovary (CHO-K1) cells were determined. D,L-buthionine-(S,R)-sulfoximine (BSO) was assayed to determine the role of GSH in the protection against carbamate cytotoxicity. Pre-treatment with 60 microM BSO, induced a significant decrease in the glutathione reductase (GR; 64-141%), the glutathione peroxidase (GPx; 10-30%) and the glutathione S-transferase (GST; 59-93%) activities, and its GSH levels (79-85%), while the oxidized glutathione (GSSG) levels significantly increased (64-78%) respect to experiment non-BSO-pretreated. Carbamates BSO pre-treated vs. non-BSO pre-treated showed a significant increase in malondialdehyde (MDA) production (from 13% to 52% vs. 25% to 93%). These data suggest that carbamates could injure CHO-K1 cells via oxidative stress by the increase of MDA production; moreover, BSO enhance the oxidative damage caused by carbamates. However, the glutathione system protects cells from carbamates damage.

  7. Isolation of oxamyl-degrading bacteria and identification of cehA as a novel oxamyl hydrolase gene

    Directory of Open Access Journals (Sweden)

    Konstantina eRousidou


    Full Text Available Microbial degradation is the main process controlling the environmental dissipation of the nematicide oxamyl. Despite that, little is known regarding the microorganisms involved in its biotransformation. We report the isolation of four oxamyl-degrading bacterial strains from an agricultural soil exhibiting enhanced biodegradation of oxamyl. Multilocus sequence analysis (MLSA assigned the isolated bacteria to different subgroups of the genus Pseudomonas. The isolated bacteria hydrolyzed oxamyl to oxamyl oxime, which was not further transformed, and utilized methylamine as a C and N source. This was further supported by the detection of methylamine dehydrogenase in three of the four isolates. All oxamyl-degrading strains carried a gene highly homologous to a carbamate-hydrolase gene cehA previously identified in carbaryl- and carbofuran-degrading strains. Transcription analysis verified its direct involvement in the hydrolysis of oxamyl. Selected isolates exhibited relaxed degrading specificity and transformed all carbamates tested including the oximino carbamates aldicarb and methomyl (structurally related to oxamyl and the aryl-methyl carbamates carbofuran and carbaryl which share with oxamyl only the carbamate moiety

  8. Isolation of Oxamyl-degrading Bacteria and Identification of cehA as a Novel Oxamyl Hydrolase Gene (United States)

    Rousidou, Konstantina; Chanika, Eleni; Georgiadou, Dafne; Soueref, Eftychia; Katsarou, Demetra; Kolovos, Panagiotis; Ntougias, Spyridon; Tourna, Maria; Tzortzakakis, Emmanuel A.; Karpouzas, Dimitrios G.


    Microbial degradation is the main process controlling the environmental dissipation of the nematicide oxamyl. Despite that, little is known regarding the microorganisms involved in its biotransformation. We report the isolation of four oxamyl-degrading bacterial strains from an agricultural soil exhibiting enhanced biodegradation of oxamyl. Multilocus sequence analysis (MLSA) assigned the isolated bacteria to different subgroups of the genus Pseudomonas. The isolated bacteria hydrolyzed oxamyl to oxamyl oxime, which was not further transformed, and utilized methylamine as a C and N source. This was further supported by the detection of methylamine dehydrogenase in three of the four isolates. All oxamyl-degrading strains carried a gene highly homologous to a carbamate-hydrolase gene cehA previously identified in carbaryl- and carbofuran-degrading strains. Transcription analysis verified its direct involvement in the hydrolysis of oxamyl. Selected isolates exhibited relaxed degrading specificity and transformed all carbamates tested including the oximino carbamates aldicarb and methomyl (structurally related to oxamyl) and the aryl-methyl carbamates carbofuran and carbaryl which share with oxamyl only the carbamate moiety. PMID:27199945

  9. Autocatalysis in lithium diisopropylamide-mediated ortholithiations. (United States)

    Singh, Kanwal J; Hoepker, Alexander C; Collum, David B


    Ortholithiation of 3-fluorophenyl-N,N-diisopropyl carbamate by lithium diisopropylamide (LDA) in THF at -78 degrees C affords unusual rate behavior including linear decays of the carbamate, delayed formation of LDA-aryllithium mixed dimers, and evidence of autocatalysis. A mechanistic model in conjunction with numeric integration methods accounts for the time-dependent changes in concentration. The two critical rate-limiting steps in the model entail (1) an LDA dimer-based metalation of arylcarbamate, and (2) a rate-limiting condensation of the resulting aryllithium with the LDA dimer to form two isomeric LDA-ArLi mixed dimers. One isomer elicits a highly efficient (post-rate-limiting) metalation of aryl carbamate, in turn, regenerating aryllithium. The prevalence and implications of such autocatalysis are discussed.

  10. Synthesis of Energetic Nitrocarbamates from Polynitro Alcohols and Their Potential as High Energetic Oxidizers. (United States)

    Axthammer, Quirin J; Krumm, Burkhard; Klapötke, Thomas M


    A new synthesis strategy for the preparation of energetic carbamates and nitrocarbamates starting from readily available polynitro alcohols is introduced. The efficient synthesis of mainly new carbamates was performed with the reactive chlorosulfonyl isocyanate (CSI) reagent. The carbamates were nitrated using mixed acid to form the corresponding primary nitrocarbamates. The thermal stability of all synthesized compounds was studied using differential scanning calorimetry, and the energies of formation were calculated on the CBS-4 M level of theory. Detonation parameters and propulsion properties were determined with the software package EXPLO5 V6.02. Furthermore, for all new substances single-crystal X-ray diffraction studies were performed and are presented and discussed as Supporting Information.

  11. Benzoxazolinone detoxification by N-Glucosylation: The multi-compartment-network of Zea mays L. (United States)

    Schulz, Margot; Filary, Barbara; Kühn, Sabine; Colby, Thomas; Harzen, Anne; Schmidt, Jürgen; Sicker, Dieter; Hennig, Lothar; Hofmann, Diana; Disko, Ulrich; Anders, Nico


    The major detoxification product in maize roots after 24 h benzoxazolin-2(3H)-one (BOA) exposure was identified as glucoside carbamate resulting from rearrangement of BOA-N-glucoside, but the pathway of N-glucosylation, enzymes involved and the site of synthesis were previously unknown. Assaying whole cell proteins revealed the necessity of H2O2 and Fe(2+) ions for glucoside carbamate production. Peroxidase produced BOA radicals are apparently formed within the extraplastic space of the young maize root. Radicals seem to be the preferred substrate for N-glucosylation, either by direct reaction with glucose or, more likely, the N-glucoside is released by glucanase/glucosidase catalyzed hydrolysis from cell wall components harboring fixed BOA. The processes are accompanied by alterations of cell wall polymers. Glucoside carbamate accumulation could be suppressed by the oxireductase inhibitor 2-bromo-4´-nitroacetophenone and by peroxidase inhibitor 2,3-butanedione. Alternatively, activated BOA molecules with an open heterocycle may be produced by microorganisms (e.g., endophyte Fusarium verticillioides) and channeled for enzymatic N-glucosylation. Experiments with transgenic Arabidopsis lines indicate a role of maize glucosyltransferase BX9 in BOA-N-glycosylation. Western blots with BX9 antibody demonstrate the presence of BX9 in the extraplastic space. Proteomic analyses verified a high BOA responsiveness of multiple peroxidases in the apoplast/cell wall. BOA incubations led to shifting, altered abundances and identities of the apoplast and cell wall located peroxidases, glucanases, glucosidases and glutathione transferases (GSTs). GSTs could function as glucoside carbamate transporters. The highly complex, compartment spanning and redox-regulated glucoside carbamate pathway seems to be mainly realized in Poaceae. In maize, carbamate production is independent from benzoxazinone synthesis.

  12. Designed amyloid fibers as materials for selective carbon dioxide capture. (United States)

    Li, Dan; Furukawa, Hiroyasu; Deng, Hexiang; Liu, Cong; Yaghi, Omar M; Eisenberg, David S


    New materials capable of binding carbon dioxide are essential for addressing climate change. Here, we demonstrate that amyloids, self-assembling protein fibers, are effective for selective carbon dioxide capture. Solid-state NMR proves that amyloid fibers containing alkylamine groups reversibly bind carbon dioxide via carbamate formation. Thermodynamic and kinetic capture-and-release tests show the carbamate formation rate is fast enough to capture carbon dioxide by dynamic separation, undiminished by the presence of water, in both a natural amyloid and designed amyloids having increased carbon dioxide capacity. Heating to 100 °C regenerates the material. These results demonstrate the potential of amyloid fibers for environmental carbon dioxide capture.

  13. Resistance risk assessment of 2 insect development inhibitors, diflubenzuron and cyromazine, for control of the housefly musca-domestica l

    DEFF Research Database (Denmark)

    Keiding, J.; El-Khodary, A.S.; Jespersen, Jørgen B.


     Laboratory selection with diflubenzuron (DFB) and cyromazine (CYR) was carried out with strains of houseflies collected on Danish farms. The adult flies were multiresistant to organophosphorus. carbamate and pyrethroid insecticides. Susceptibility to the larvicidal effect of DFB or CYR was monit...... Laboratory selection with diflubenzuron (DFB) and cyromazine (CYR) was carried out with strains of houseflies collected on Danish farms. The adult flies were multiresistant to organophosphorus. carbamate and pyrethroid insecticides. Susceptibility to the larvicidal effect of DFB or CYR...

  14. Synthesis of novel aryl(heteroaryl)sulfonyl ureas of possible biological interest. (United States)

    Saczewski, Franciszek; Kuchnio, Anna; Samsel, Monika; Łobocka, Marta; Kiedrowska, Agnieszka; Lisewska, Karolina; Saczewski, Jarosław; Gdaniec, Maria; Bednarski, Patrick J


    The course of reaction of aryl and heteroaryl sulfonamides with diphenylcarbonate (DPC) and 4-dimethylaminopyridine (DMAP) was found to depend on the pKa of the sulfonamide used. Aryl sulfonamides with pKa approximately 10 gave 4-dimethylamino-pyridinium arylsulfonyl-carbamoylides, while the more acidic heteroaryl sulfonamides (pKa approximately 8) furnished 4-dimethylaminopyridinium heteroarylsulfonyl carbamates. Both the carbamoylides and carbamate salts reacted with aliphatic and aromatic amines with the formation of appropriate aryl(heteroaryl)sulfonyl ureas, and therefore, can be regarded as safe and stable substitutes of the hazardous and difficult to handle aryl(heteroaryl)sulfonyl isocyanates.

  15. Synthesis of Novel Aryl(heteroarylsulfonyl Ureas of Possible Biological Interest

    Directory of Open Access Journals (Sweden)

    Maria Gdaniec


    Full Text Available The course of reaction of aryl and heteroaryl sulfonamides with diphenylcarbonate (DPC and 4-dimethylaminopyridine (DMAP was found to depend on the pKa of the sulfonamide used. Aryl sulfonamides with pKa ~ 10 gave 4-dimethylamino-pyridinium arylsulfonyl-carbamoylides, while the more acidic heteroaryl sulfonamides (pKa ~ 8 furnished 4-dimethylaminopyridinium heteroarylsulfonyl carbamates. Both the carbamoylides and carbamate salts reacted with aliphatic and aromatic amines with the formation of appropriate aryl(heteroarylsulfonyl ureas, and therefore, can be regarded as safe and stable substitutes of the hazardous and difficult to handle aryl(heteroarylsulfonyl isocyanates.

  16. Carbon dioxide capture in 2-aminoethanol aqueous solution from ab initio molecular dynamics simulations (United States)

    Kubota, Yoshiyuki; Ohnuma, Toshiharu; Bučko, Tomáš


    The reaction of carbon dioxide (CO2) with aqueous 2-aminoethanol (MEA) has been investigated using both blue moon ensemble and metadynamics approaches combined with ab initio molecular dynamics (AIMD) simulations. The AIMD simulations predicted the spontaneous deprotonation of the intermediate compound, MEA zwitterion, and they were used to study two possible routes for subsequent proton transfer reactions: the formation of the protonated MEA and the formation of MEA carbamic acid. The free-energy curve depicted by blue moon ensemble technique supported the favorable deprotonation of MEA zwitterion. The overall free-energy profile showed the favorable formation of the ionic products of MEA carbamate ion and protonated MEA.

  17. Protecting-Group-Free Synthesis of 2-Deoxy-Aza-Sugars

    Directory of Open Access Journals (Sweden)

    Mattie Simon Maria Timmer


    Full Text Available The protecting-group-free asymmetric synthesis of 1,2,4-trideoxy-1,4-imino-L-xylitol is readily achieved in five steps from 2-deoxy-D-ribose and with an overall yield of 48%. Key in this synthesis is the application of our recently developed Vasella-reductive amination and carbamate annulation methodologies to the synthesis of 2-deoxy-aza-sugars. The carbamate annulation occurred with excellent yield and diastereoselectively (>20:1 d.r., in favour of the 3,4-cis isomer.

  18. Caracterização e quantificação de contaminantes em aguardentes de cana

    Directory of Open Access Journals (Sweden)

    Lidiany Mendonça Zacaroni


    Full Text Available The objective of the present study was the evaluation of the presence of organic and inorganic contaminants in samples of aged cachaça from the South of the state of Minas Gerais. Furfural, methanol and copper were determined by colorimetric reactions, while the analyses of ethyl carbamate and acrolein were performed by GC/MS and HPLC, respectively. High levels of furfural and copper were obtained. All samples showed concentrations below the established by legislation for the ethyl carbamate, and for acrolein, only one sample showed higher levels. Methanol was not detected in the samples.

  19. Synthesis and evaluation of potential inhibitors of human and Escherichia coli histidine triad nucleotide binding proteins. (United States)

    Bardaweel, Sanaa K; Ghosh, Brahma; Wagner, Carston R


    Based on recent substrate specificity studies, a series of ribonucleotide based esters and carbamates were synthesized and screened as inhibitors of the phosphoramidases and acyl-AMP hydrolases, Escherichia coli Histidine Triad Nucleotide Binding Protein (ecHinT) and human Histidine Triad Nucleotide Binding Protein 1 (hHint1). Using our established phosphoramidase assay, K(i) values were determined. All compounds exhibited non-competitive inhibition profiles. The carbamate based inhibitors were shown to successfully suppress the Hint1-associated phenotype in E. coli, suggesting that they are permeable intracellular inhibitors of ecHinT.

  20. Study of a Multi-Phase Hybrid Heat Exchanger-Reactor (HEX Reactor): Part 2 - Numerical Prediction of Thermal Performance (Postprint) (United States)


    300 College Park, Dayton, OH 45469, United States a r t i c l e i n f oArticle history : Available online 16 November 2013 Keywords: Ammonium carbamate...readily available in pow- der form as a cheap byproduct of urea synthesis [7]. AC undergoes a reversible solid–gas decomposition reaction, shown below...Manage. 23 (1983) 55–63. [15] R.N. Bennet, P.D. Ritchie, D. Roxburgh, J. Thomson, The system ammonia carbon dioxide ammonium carbamate. Part I. – the

  1. Pyrethroid and DDT Resistance and Organophosphate Susceptibility among Anopheles spp. Mosquitoes, Western Kenya. (United States)

    Wanjala, Christine L; Mbugi, Jernard P; Ototo, Edna; Gesuge, Maxwell; Afrane, Yaw A; Atieli, Harrysone E; Zhou, Guofa; Githeko, Andrew K; Yan, Guiyun


    We conducted standard insecticide susceptibility testing across western Kenya and found that the Anopheles gambiae mosquito has acquired high resistance to pyrethroids and DDT, patchy resistance to carbamates, but no resistance to organophosphates. Use of non-pyrethroid-based vector control tools may be preferable for malaria prevention in this region.


    Carbofuran, known as 2, 3-dihydro-2, 2-dimethyl-7-benzofuranyl-N-methylcarbamate, is a broad spectrum N-methyl carbamate pesticide. Carbofuran and its metabolite, 3-hydroxycarbofuran, exert their toxicity by reversibly inhibiting acetylcholinesterase (AChE). Carbofuran is widel...


    To compare the toxicity of seven N-methyl carbamates, time course profiles for brain and red blood cell (RBC) cholinesterase (ChE) inhibition were established for each. Adult, male, Long Evans rats (n=4-5 dose group) were dosed orally with either carbaryl (30 mg/kg in corn oil); ...

  4. Synthesis and characterization of zwitterionic carbon dioxide fixing reagents

    DEFF Research Database (Denmark)

    Mikkelsen, Mette; Jørgensen, Mikkel; Krebs, Frederik C


    The synthesis of three amine-based carbon dioxide fixing reagents is presented. The reagents were designed so that they would be able to bind CO2 reversibly through the formation of the well known carbamates that was stabilized through forming a zwitterion. CO2 fixing experiments were performed...

  5. Palladium-Catalyzed Carbonylation of Primary Amines in Supercritical Carbon Dioxide

    Institute of Scientific and Technical Information of China (English)

    李金恒; 江焕峰; 陈鸣才


    The chemoselectity of the palladimm-catalyzed carbonylation of amines was affected by the addition of MeOH in supercritical carbon dioxide. The results show different selectivity in supercritical carbon dioxide CO2(sc) from that in alcohol.Methyl carbamate and its derivatives were obtained in high yields in CO2(sc).

  6. An expedient and new synthesis of pyrrolo[1,2-b]pyridazine derivatives

    Directory of Open Access Journals (Sweden)

    Rajeshwar Reddy Sagyam


    Full Text Available The reaction of 2-[2-(4-fluorophenyl-2-oxo-1-phenylethyl]-4-methyl-3-oxo-pentanoic acid phenylamide with tertiary butyl carbazate and subsequent condensation of the resulting carbamate derivative with a chalcone provided a facile new approach to pyrrolo[1,2-b]pyridazine derivatives.

  7. The Transition States for CO2 Capture by Substituted Ethanolamines

    NARCIS (Netherlands)

    Gangarapu, S.; Marcelis, A.T.M.; Alhamed, Y.A.; Zuilhof, H.


    Quantum chemical studies are used to understand the electronic and steric effects on the mechanisms of the reaction of substituted ethanolamines with CO2. SCS-MP2/6-311+G(2d,2p) calculations are used to obtain the activation energy barriers and reaction energies for both the carbamate and bicarbonat

  8. Carbamoylcholine analogs as nicotinic acetylcholine receptor agonists--structural modifications of 3-(dimethylamino)butyl dimethylcarbamate (DMABC)

    DEFF Research Database (Denmark)

    Hansen, Camilla Petrycer; Jensen, Anders Asbjørn; Balle, Thomas;


    Compounds based on the 3-(dimethylamino)butyl dimethylcarbamate (DMABC) scaffold were synthesized and pharmacologically characterized at the alpha(4)beta(2), alpha(3)beta(4,) alpha(4)beta(4) and alpha(7) neuronal nicotinic acetylcholine receptors (nAChRs). The carbamate functionality and a small...

  9. Anticytokinin effect on apical dominance release in in vitro cultured Rosa hybrida L.

    NARCIS (Netherlands)

    Kapchina-Toteva, V.M.; Somleva, M.; Telgen, van H.J.


    Effects of two cytokinin antagonists - 2-chloro-4-cyclobutyl-amino-6-ethylamino-1,3,5-triazine and N-(4-pyridyl)-O-(4-chlorophenyl)carbamate - on bud break and outgrowth in single nodes from two Rosa hybrida cultivars differing in their apical dominance were studied. The compounds were applied at th


    The effects of N-methyl carbamate pesticides on the photic after discharge (PhAD) of flash evoked potentials (FEPs) and the relationship between inhibition of brain cholinesterase (ChE) activity and the PhAD were evaluated. FEPs were recorded in Long Evans rats treated with physo...


    Enzymatic test kits, generally designed to be handheld and portable, detect the presence of chemical agents, carbamate pesticides, and/or organophosphate pesticides by relying on the reaction of the cholinesterase enzyme. Under normal conditions, the enzyme reacts as expected wi...

  12. Knockdown and lethal effects of eight commercial nonconventional and two pyrethroid insecticides against moderately permethrin-resistant adult bed bugs, Cimex lectularius (L.) (Hemiptera: Cimicidae) (United States)

    The common bed bug, Cimex lectularius (L.) (Hemiptera: Cimicidae) is undergoing a rapid resurgence in the United States during the last decade which has created a notable pest management challenge largely because the pest has developed resistance against DDT, organophosphates, carbamates, and pyreth...

  13. Comparative in vitro-in vivo percutaneous absorption of the pesticide propoxur

    NARCIS (Netherlands)

    Sandt, J.J.M. van de; Meuling, W.J.A.; Elliott, G.R.; Cnubben, N.H.P.; Hakkert, B.C.


    In vitro and in vivo skin absorption of the pesticide propoxur (2-isopropoxyphenyl N-methyl carbamate, commercially Baygon(TM) and Unden(TM); log Po/w 1.56, MW 209.2) was investigated. In vivo studies were performed in rats and human volunteers, applying the test compound to the dorsal skin and the

  14. In Vitro Studies of Neurotoxic Substances (United States)


    less neurotoxic to mammals and, in the case of pesticides, more toxic to insects . Validated in vitro test systems developed specifically for the...1974, Johnson (11) reported that phosphinates behaved like carbamates and sulphonates against NTE, inhibiting it but not causing OPIDN. p It has been

  15. Identification and characterization of mutations in housefly (Musca domestica) acetylcholinesterase involved in insecticide resistance

    DEFF Research Database (Denmark)

    Walsh, Sinead B.; Dolden, Tracey A.; Moores, Graham D.


    Acetylcholinesterase (AChE) insensitive to organophosphate and carbamate insecticides has been identified as a major resistance mechanism in numerous arthropod species. However, the associated genetic changes have been reported in the AChE genes from only three insect species; their role in confe...... of the AChE protein from Torpedo californica and D. melanogaster....

  16. Carbamato de etila em bebidas alcoólicas (cachaça, tiquira, uísque e grapa

    Directory of Open Access Journals (Sweden)

    Andrade-Sobrinho Luiz Gualberto de


    Full Text Available The presence of ethyl carbamate in cachaças, tiquiras, whiskies and grapes was investigated by GC-MS, monitoring the m/z 62 ion. The external standard method was used for quantitation in 188 samples (126 cachaças, 37 tiquiras, 6 grappas and 19 whiskies. The results of the study for cachaça were analysed considering the geographic origin, distillation type (still or column, bottle coloration (amber or transparent and ageing. The average contents of ethyl carbamate in cachaças and tiquiras were 0.77 and 2.4 mg L-1, respectively. These values were higher than the mean concentration found in grapes (0.045 mg L-1 and whiskies (0.14 mg L-1. On average the cachaças distilled in column tend to present higher values of ethyl carbamate than those from still. In the sampling studied it was not possible to define a correlation between content of ethyl carbamate, bottle coloration and ageing time.


    Propoxur is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response following stimulation of the visual system with flashes of light. They ar...


    Carbaryl is a widely used N-methyl carbamate pesticide that acts by inhibiting cholinesterases (ChE), which may lead to cholinergic toxicity. Flash evoked potentials (FEPs) are a neurophysiological response often used to detect central nervous system (CNS) changes following expos...


    Carbaryl and propoxur are N-methyl carbamate pesticides (NMCs) which are part of the EPA’s cumulative risk assessments for NMCs. These NMCs inhibit cholinesterase (ChE) activity and may lead to cholinergic disruption of CNS function. We used decreases in the PhAD of FEPs to indic...

  20. Cholinesterase Inhibition and Depression of the Photic After Discharge of Flash Evoked Potentials Following Acute or Repeated Exposures to a Mixture of Carbaryl and Propoxur (United States)

    While information exists regarding inhibition of cholinesterase (ChE) activity, little is known about neurophysiological changes produced by a mixture of N-methyl carbamate pesticides. Previously, we reported that acute treatment with propoxur or carbaryl decreased the duration o...

  1. Toward rational design of amines for CO2 capture: Substituent effect on kinetic process for the reaction of monoethanolamine with CO2. (United States)

    Xie, Hongbin; Wang, Pan; He, Ning; Yang, Xianhai; Chen, Jingwen


    Amines have been considered as promising candidates for post-combustion CO2 capture. A mechanistic understanding for the chemical processes involved in the capture and release of CO2 is important for the rational design of amines. In this study, the structural effects of amines on the kinetic competition among three typical products (carbamates, carbamic acids and bicarbonate) from amines+CO2 were investigated, in contrast to previous thermodynamic studies to tune the reaction of amines with CO2 based on desirable reaction enthalpy and reaction stoichiometry. We used a quantum chemical method to calculate the activation energies (Ea) for the reactions of a range of substituted monoethanolamines with CO2 covering three pathways to the three products. The results indicate that the formation of carbamates is the most favorable, among the three considered products. In addition, we found that the Ea values for all pathways linearly correlate with pKa of amines, and more importantly, the kinetic competition between carbamate and bicarbonate absorption pathways varies with pKa of the amines, i.e. stronger basicity results in less difference in Ea. These results highlight the importance of the consideration of kinetic competition among different reaction pathways in amine design.

  2. Inhibition of Albendazole and Oxfendazole on the Activity of Fumaric Reductase in Cysticercus cellulosae

    Institute of Scientific and Technical Information of China (English)

    GAO Xue-jun; LI Qing-zhang; LI Xia


    The activity of fumaric reductase in Cysticercus cellulosae tissue homogenate with albendazole and oxfendazole individually was detected. Results showed that the two kinds of drugs both could inhabite the activity of fumaric reductase. The results indicate that the mechanism of action of benzimidazole carbamate drugs is probably inhabiting the complex of fumaric reductase noncompetently, thus lead to the exhaostion of energy and death.

  3. Diagnosis & Treatment of Poisoning by Pesticides. (United States)

    Environmental Protection Agency, Washington, DC. Office of Pesticide Programs.

    This report succinctly discusses the steps necessary to diagnose and treat poisoning from pesticides, especially organophosphates, carbamates and chlorinated hydrocarbons. Immediate and continuing steps in the care of poisoning victims are outlined with supportive information on where to locate emergency assistance. (CS)

  4. GenBank blastx search result: AK243321 [KOME

    Lifescience Database Archive (English)

    Full Text Available hine carbamoyl transferase (argF) gene, partial cds; xasA gene, complete sequence; LabD (labD) and putative ...carbamate kinase-like carbamyl phosphate synthase (cpkA) genes, complete cds; and LabE (labE) gene, partial cds. BCT 1e-104 1 ...

  5. GenBank blastx search result: AK243192 [KOME

    Lifescience Database Archive (English)

    Full Text Available hine carbamoyl transferase (argF) gene, partial cds; xasA gene, complete sequence; LabD (labD) and putative ...carbamate kinase-like carbamyl phosphate synthase (cpkA) genes, complete cds; and LabE (labE) gene, partial cds. BCT 4e-20 1 ...

  6. A facile microwave-assisted synthesis of 8,9-cycloalkathieno[3,2-] [1,2,4]triazolo[1,5-]pyrimidin-5(6)-ones

    Indian Academy of Sciences (India)

    Rajwinder Kaur; D Pran Kishore; B Lakshmi Narayana; K Venkat Rao; C Balakumar; V Rajkumar; A Raghuram Rao


    A new series of fused thieno[3,2-][1,2,4]triazolo[1,5-]pyrimidinones was synthesized by condensation of ethyl-3-cyano-4,5,6,7-tetrahydrobenzo[]thiophene-2-yl carbamate with aryl acid hydrazides in quantitative yields using a facile, one-pot procedure under microwave-assisted conditions.

  7. Preparation of tritium labelled synthanecine A and its bis-N-ethylcarbamate

    Energy Technology Data Exchange (ETDEWEB)

    Mattocks, A.R. (Medical Research Council, Carshalton (UK))


    A procedure is described for incorporating tritium into the 3-CH/sub 2/ side chain of synthanecine A, and preparing the carbamate, 2,3-bis-N-ethylcarbamoyloxymethyl-1-methyl-3-pyrroline, a hepatotoxic pyrrolizidine alkaloid analogue. The pyrrolizidine amino alcohol, retronecine, can be tritium labelled in a similar way.

  8. Evaluation of the Pollution of surface waters in the basin of west Algeria by Organo chlorine and Organophosphorus pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Hadjel, M.; Berkok, N.


    The pollutants are pesticides which cover a whole range of chemicals designed to protect plants from pests and destroy unwanted plants. There are a very large number of pesticides and we do here that some of the major families (organo chlorine insecticides, organophosphates, carbamates, pyrethroids, phenylcyclohexyl, herbicides. (Author)

  9. Deciphering the origin of cooperative catalysis by dirhodium acetate and chiral spiro phosphoric acid in an asymmetric amination reaction. (United States)

    Kisan, Hemanta K; Sunoj, Raghavan B


    The mechanism of asymmetric amination of diazo-acetate by tert-butyl carbamate catalyzed by dirhodium tetra(trifluoro)acetate and chiral SPINOL-phosphoric acid is examined using DFT (M06 and B3LYP) computations. A cooperative participation of both catalysts is noticed in the stereo-controlling transition state of the reaction.

  10. Chemical and Molecular Descriptors for the Reactivity of Amines with CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Anita S.; Kitchin, John R.


    Amine-based solvents are likely to play an important role in CO{sub 2} capture applications in the future, and the identification of amines with superior performance will facilitate their use in CO{sub 2} capture. While some improvements in performance will be achieved through process modifications, modifying the CO{sub 2} capture performance of an amine also implies in part an ability to modify the reactions between the amine and CO{sub 2} through development of new functionalized amines. We present a computational study of trends in the reactions between CO{sub 2} and functionalized amines with a focus on identifying molecular descriptors that determine trends in reactivity. We examine the formation of bicarbonate and carbamate species on three classes of functionalized amines: alkylamines, alkanolamines, and fluorinated alkylamines including primary, secondary and tertiary amines in each class. These functional groups span electron-withdrawing to donating behavior, hydrogen-bonding, extent of functionalization, and proximity effects of the functional groups. Electron withdrawing groups tend to destabilize CO{sub 2} reaction products, whereas electron-donating groups tend to stabilize CO{sub 2} reaction products. Hydrogen bonding stabilizes CO{sub 2} reaction products. Electronic structure descriptors based on electronegativity were found to describe trends in the bicarbonate formation energy. A chemical correlation was observed between the carbamate formation energy and the carbamic acid formation energy. The local softness on the reacting N in the amine was found to partially explain trends carbamic acid formation energy.


    Oxidative stress (OS) plays an important role in susceptibility and disease in old age. Understanding age-related susceptibility is crucial in assessing the human health risks of chemicals. Growing evidence implicates as in carbamate toxicity in addition to cholinesterase-inhibit...

  12. Installation Restoration Program. Phase I. Records Search. Seymour Johnson Air Force Base, North Carolina. (United States)


    environments, e.g., heavy metals CARBON REMOVER: A material containing approximately 15 percent butyl cellusolve and 10 percent monoethanol amine and...S-Triazine N-(phosphonomethyl) Round-Up 41% E 500 Glycine (Isopropyl- amine salt) I-Naphthyl-Methyl- Sevimol liquid 40% 150 Carbamate Sevin D 5% 4

  13. Global Alterations in Gene Expression During Organophosphate Pesticide Intoxication and Recovery: Interim Report (United States)


    tried; all proved satisfactory. The use of organic milk is intended to reduce or eliminate nematicides that may be present in commercial milk. The...and Environmental Health, Part B 2:161-181. Pree, D. J., J. L. Townshend, and D. E. Archibald. 1989. Carbamate and Organophosphorous Nematicides

  14. Carbon dioxide transport in alligator blood and its erythrocyte permeability to anions and water

    DEFF Research Database (Denmark)

    Jensen, F B; Wang, T; Jones, D R


    Deoxygenation of alligator red blood cells (RBCs) caused binding of two HCO3- equivalents per hemoglobin (Hb) tetramer at physiological pH. At lowered pH, some HCO3- binding also occurred to oxygenated Hb. The erythrocytic total CO2 content was large, and Hb-bound HCO3-, free HCO3-, and carbamate...


    Here we use a hamster animal model to identify early pregnancy loss due to an acute chemical exposure to the female during the perifertilization interval. The fungicide carbendazim (methyl 1H-benzimidazole-2-carbamate), a microtubule poison with antimitotic activity, was selected...

  16. Theoretical study of differential enthalpy of absorption of CO2 with MEA and MDEA as a function of temperature. (United States)

    Gupta, Mayuri; da Silva, Eirik F; Hartono, Ardi; Svendsen, Hallvard F


    Temperature dependent correlations for enthalpy of deprotonation, carbamate formation, and heat of absorption of the overall reaction between aqueous MEA and MDEA and gaseous CO2 are calculated on the basis of computational chemistry based ln K values input to the Gibbs-Helmholtz equation. Temperature dependency of reaction equilibrium constants for deprotonation and carbamate formation reactions is calculated with the SM8T continuum solvation model coupled with density functional theoretical calculations at the B3LYP/6-311++G(d,p) level of theory. Calculated reaction equilibrium constants and enthalpies of individual reactions and overall heat of absorption are compared against experimental data in the temperature range 273.15-373 K. Temperature dependent correlations for different reaction equilibrium constants and enthalpies of reactions are given. These correlated results can be used in thermodynamic models such as UNIQUAC and NRTL for better understanding of post-combustion CO2 capture solvent chemistry.

  17. Molecular modeling and anticholinesterasic activity of novel 2-arylaminocyclohexyl N,N-dimethylcarbamates

    Energy Technology Data Exchange (ETDEWEB)

    Bagatin, Mariane C.; Candido, Augusto A.; Basso, Ernani A.; Gauze, Gisele F., E-mail: [Universidade Estadual de Maringa (UEM), PR (Brazil). Departamento de Quimica; Pinheiro, Glaucia M. S.; Hoeehr, Nelci F. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Faculdade de Ciencias Medicas. Departamento de Patologia Clinica; Machinski Junior, Miguel; Mossini, Simone A.G. [Universidade Estadual de Maringa (UEM), PR (Brazil). Departamento de Ciencias Basicas da Saude


    This work reports a detailed theoretical and experimental study of the novel isomer series cis- and trans-2-arylaminocyclohexyl N,N-dimethylcarbamates as potential inhibitors of cholinesterases. In vitro inhibition assay by Ellman's method with human blood samples showed that the new carbamates are selective to the inhibition of enzyme butyrylcholinesterase (BuChE) with maximum inhibition of 90% and IC{sub 50} of 6 and 8 mmol L{sup -1} for the more actives compounds of the series. Molecular modeling studies point to significant differences for the conformations of the compounds in the active sites of enzymes BuChE and acetylcholinesterase (AChE). The results show that the compounds interact more effectively with the active site of enzyme BuChE since the carbamate group is close to the key residues of the catalytic triad. (author)

  18. Simultaneous analysis of D-alanine, D-aspartic acid, and D-serine using chiral high-performance liquid chromatography-tandem mass spectrometry and its application to the rat plasma and tissues. (United States)

    Karakawa, Sachise; Shimbo, Kazutaka; Yamada, Naoyuki; Mizukoshi, Toshimi; Miyano, Hiroshi; Mita, Masashi; Lindner, Wolfgang; Hamase, Kenji


    A highly sensitive and selective chiral LC-MS/MS method for D-alanine, D-aspartic acid and D-serine has been developed using the precolumn derivatization reagents, 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AccQ-Tag) or p-N,N,N-trimethylammonioanilyl N'-hydroxysuccinimidyl carbamate iodide (TAHS). The thus N-tagged enantiomers of the derivatized amino acids were nicely separated within 20min using the cinchona alkaloid-based zwittterionic ion-exchange type enantioselective column, Chiralpak ZWIX(+). The selected reaction monitoring was applied for detecting the target d-amino acids in biological matrices. By using the present chiral LC-MS/MS method, the three d-amino acids and their l-forms could be simultaneously determined in the range of 0.1-500nmol/mL. Finally, the technique was successfully applied to rat plasma and tissue samples.

  19. Efficient Synthesis of Primary Nitrocarbamates of Sugar Alcohols: From Food to Energetic Materials. (United States)

    Axthammer, Quirin J; Klapötke, Thomas M; Krumm, Burkhard


    The synthesis of various new polyvalent nitrocarbamates derived from sugar alcohols was accomplished by an economically benign two-step synthesis. The precursor carbamates were synthesized with the reagent chlorosulfonyl isocyanate (CSI) and further nitrated using mixed acid. The starting materials, sugar alcohols, are renewable biomass, mainly used in food and cosmetic industry. The structures of one carbamate and one nitrocarbamate were exemplary described by single-crystal X-ray-analysis. The heat of formation is calculated by the use of isodesmic reactions and the energetic performance data were estimated. All compounds were fully characterized by elemental analysis, vibrational spectroscopy, (1)H, (13)C, and (14/15)N NMR spectroscopy and thermal analysis (DSC). The nitrocarbamates exhibit good detonation performance and have significantly lower sensitivities compared to the commonly used nitrate ester explosive PETN.

  20. Synthesis and Antibiotic Activity of Mebendazole Derivatives of Pharmacological Interest

    Directory of Open Access Journals (Sweden)

    Kavita Rathore


    Full Text Available Mebendazole is a well known anti-helimintic and belongs to the benzimidazole group of medicines. In order to achieve better medicinal results, i.e. enhanced activity and low toxicity, structural modifications are made in the existing drugs. Some 5-benzoyl-N-[1-(alkoxyphthalimido benzimidazol-2-yl] carbamic acid methyl ester (3a-c and 5-benzoyl-N-[1-(2,3-bis oxyphthalimido∕oxysuccinimido propyl benzimidazol-2-yl carbamic acid methyl ester (7a-b have been synthesized from two different routes. Structures of the compounds have been established on the basis of elemental analysis and spectral studies. All the synthesized compounds (3a-c and (7a-b were assayed in vitro for antimicrobial activity against mebendazole (itself and standard [ciprofloxacin (antibacterial and fluconazole (antifungal].

  1. Mechanochemical Synthesis of Visible Light Sensitive Titanium Dioxide Photocatalyst

    Directory of Open Access Journals (Sweden)

    Jan Šubrt


    Full Text Available Phase transition of anatase nanoparticles into the phases TiO2-II and rutile under grinding was studied. The addition of ammonium carbamate to the reaction mixture inhibits the phase conversion and the cold welding of particles. The UV-visible absorption spectrum showed narrowing the band gap width after grinding with an ammonium carbamate additive resulting in shift of the light absorption of the ground sample towards the visible region. By EPR, intensive formation of OH• radical at irradiation of the sample with both UV (λ > 300 nm and visible (λ > 435 nm light was observed. High photocatalytic activity of the ground sample in visible light region was demonstrated also by measurement of kinetics of the photocatalytic decomposition of 4-chlorophenol.

  2. Synthesis and Evaluation of Novel RSK Inhibitors in a Living Human Breast Model (United States)


    identify a drug for breast cancer based on SL0101 that works by inhibiting RSK, by designing and chemically synthesizing analogues of SL0101 that improve... synthesize analogues of SL0101, with the assistance of a computational model of SL0101 bound to RSK, that improve on these deficiencies and to...Project Summary Task 1: Synthesis and biological evaluation of 3’,4’-carbamate analogues of SL0101. I will first synthesize N- methyl and N,N-dimethyl

  3. Computational characterisation of the interactions between human ST6Gal I and transition-state analogue inhibitors: insights for inhibitor design. (United States)

    Montgomery, Andrew; Szabo, Rémi; Skropeta, Danielle; Yu, Haibo


    Human β-galactoside α-2,6-sialyltransferase I (hST6Gal I) catalyses the synthesis of sialylated glycoconjugates involved in cell-cell interactions. Overexpression of hST6Gal I is observed in many different types of cancers, where it promotes metastasis through altered cell surface sialylation. A wide range of sialyltransferase (ST) inhibitors have been developed based on the natural donor, cytidine 5'-monophosphate N-acetylneuraminic acid (CMP-Neu5Ac). Of these, analogues that are structurally similar to the transition state exhibit the highest inhibitory activity. In order to design inhibitors that are readily accessible synthetically and with favourable pharmacokinetic properties, an investigation of the replacement of the charged phosphodiester-linker, present in many ST inhibitors, with a potential neutral isostere such as a carbamate or a 1,2,3-triazole has been undertaken. To investigate this, molecular docking and molecular dynamics simulations were performed. These simulations provided an insight into the binding mode of previously reported phosphodiester-linked ST inhibitors and demonstrated that targeting the proposed sialyl acceptor site is a viable option for producing selective inhibitors. The potential for a carbamate- or triazole-linker as an isosteric replacement for the phosphodiester in transition-state analogue ST inhibitors was established using molecular docking. Molecular dynamics simulations of carbamate- and phosphodiester-linked compounds revealed that both classes exhibit consistent interactions with hST6Gal I. Overall, the results obtained from this study provide a rationale for synthetic and biological evaluation of triazole- and carbamate-linked transition-state analogue ST inhibitors as potential new antimetastatic agents.

  4. Oxidation Degradation of Aqueous Carbofuran Induced by Low Temperature Plasma (United States)

    Pu, Lumei; Gao, Jinzhang; Hu, Yusen; Liang, Huiguang; Xiao, Wen; Wang, Xingmin


    The oxidative degradation of aqueous carbofuran, a heavily used toxic carbamate insecticide by low temperature plasma, was investigated. The results show that the treatment efficiency increases with the increase in initial concentration. Raising the treatment temperature and changing the pH value can result in enhanced degradation of carbofuran in solution. The results also show that low temperature plasma treatment can effectively remove chemical oxygen demand (COD) of carbofuran in the solution.

  5. [The investigation into specific features of the distribution of carbofuran in the body of the warm-blooded animals]. (United States)

    Shormanov, V K; Galushkin, S G; Kovalenko, E A; Terskikh, A P


    The objective of the present study was to estimate the distribution of the carbamate pesticide carfbofuran in the organism of the warm-blooded animals (rats) after its intragastric administration. It was shown that large amounts of unmetabolized carbofuran were present in the internal organs and biological fluids. The highest content of carbofuran was recorded in the stomach, large and small intestines, testicles, urinary bladder, ureters, and heart.

  6. Oxidation Degradation of Aqueous Carbofuran Induced by Low Temperature Plasma

    Institute of Scientific and Technical Information of China (English)

    PU Lumei; GAO Jinzhang; HU Yusen; LIANG Huiguang; XIAO Wen; WANG Xingmin


    The oxidative degradation of aqueous carbofuran, a heavily used toxic carbamate insecticide by low temperature plasma, was investigated. The results show that the treatment efficiency increases with the increase in initial concentration. Raising the treatment temperature and changing the pH value can result in enhanced degradation of carbofuran in solution. The results also show that low temperature plasma treatment can effectively remove chemical oxygen demand (COD) of carbofuran in the solution.

  7. Urease as a Virulence Factor in Experimental Cryptococcosis


    Cox, Gary M.; Mukherjee, Jean; Cole, Garry T.; Casadevall, Arturo; Perfect, John R.


    Urease catalyzes the hydrolysis of urea to ammonia and carbamate and has been found to be an important pathogenic factor for certain bacteria. Cryptococcus neoformans is a significant human pathogenic fungus that produces large amounts of urease; thus we wanted to investigate the importance of urease in the pathogenesis of cryptococcosis. We cloned and sequenced the genomic locus containing the single-copy C. neoformans urease gene (URE1) and used this to disrupt the native URE1 in the seroty...

  8. Glass Transition Temperature Measurement for Undercured Cyanate Ester Networks: Challenges, Tips, and Tricks (Briefing Charts) (United States)


    temperature of a thermoplastic such as PVC exhibits a nearly fixed value regardless of processing-induces changes to the system • In contrast, the...Temp. (°C) A. R. Berens and I. M. Hodges, Macromolecules 1982, 15, 756 (digitized data from Fig. 2) Free-cooled PVC Bisphenol A dicyanate ester...Wet TMA Plasticization and degradation drop TG to near / below cure temperature Carbamate formation dilutes remaining –OCN groups, slows down in-situ

  9. Synthetic Organic Electrochemistry in Ionic Liquids: The Viscosity Question

    Directory of Open Access Journals (Sweden)

    Scott T. Handy


    Full Text Available Ionic liquids are obvious candidates for use in electrochemical applications due to their ionic character. Nevertheless, relatively little has been done to explore their application in electrosynthesis. We have studied the Shono oxidation of arylamines and carbamates using ionic liquids as recyclable solvents and have noted that the viscosity of the medium is a major problem, although with the addition of sufficient co-solvent, good results and excellent recovery and recycling of the ionic liquid can be achieved.

  10. Methomyl-Induced Severe Acute Pancreatitis: Possible Etiological Association

    Directory of Open Access Journals (Sweden)

    Ioannides M


    Full Text Available CONTEXT: N-methyl carbamate insecticides are widely used in homes, gardens and agriculture. They share the capacity to inhibit cholinesterase enzymes with organophosphates and therefore share similar symptomatology during acute and chronic exposures. One of the serious effects of organophosphate and carbamate intoxication is the development of acute pancreatitis and subsequent intrapancreatic fluid formation. CASE REPORT: An 18-year old Caucasian man was admitted to our Intensive Care Unit with cholinergic crisis symptomatology, after the ingestion of an unknown amount of a carbamate insecticide (methomyl. Pseudocholinesterase levels were 2 kU/L on the day of admission (reference range: 5.4-13.2 kU/L. Two days after admission, an abdominal CT scan revealed blurring of the peripancreatic fat planes, inflammation and swelling of the pancreas, and a substantial amount of ascitic fluid in the left anterior pararenal space and pelvis. Paracentesis and analysis of the ascitic fluid demonstrated findings diagnostic of pancreatic ascites. There had been no other evident predisposing factors for acute pancreatitis, other than methomyl intoxication. Eleven days after admission, pseudocholinesterase levels returned to normal, while a new abdominal CT scan revealed the formation of intrapancreatic fluid collection. The patient was discharged in good physical condition two weeks after admission. A follow up abdominal CT scan performed one month later showed a significant reduction in the size of the intrapancreatic fluid. DISCUSSION: Acute pancreatitis is not uncommon after organophosphate intoxication and carbamates share the same risk as organophosphorus pesticides. The development of acute pancreatitis and subsequent intrapancreatic fluid collection after methomyl intoxication has not previously been reported. This is the first case reported of acute pancreatitis and pancreatic ascite formation after anticholinesterase insecticide ingestion.

  11. Raptor toxicology. (United States)

    Redig, Patrick T; Arent, Lori R


    Birds of prey have demonstrated the negative impact that toxic agents can cause on animal populations and ecosystem dynamics. Lead, cholinesterase inhibitors (eg, organophosphates, carbamates), and anticoagulant rodenticides (eg, brodifacoum) are the most common toxic agents that currently affect the health of wild birds of prey in the United States. For raptors held in captivity, the list of toxic agents expands and includes toxic inhalants such as carbon monoxide and polytetrafluoroethylene. This article provides diagnostic and treatment guidelines for the toxic agents discussed.

  12. MnFe/Al2O3 Catalyst Synthesized by Deposition Precipitation for Low-Temperature Selective Catalytic Reduction of NO with NH3

    DEFF Research Database (Denmark)

    Schill, Leonhard; Putluru, Siva Sankar Reddy; Jensen, Anker Degn


    Mn-Fe/Al2O3 and Mn-Fe/TiO2 catalysts have been prepared by impregnation (IMP) and deposition precipitation (DP) and characterized with several techniques including: XRDP, N2-physisorption, NH3-TPD, H2-TPR, TGA and XPS. 40 wt% Mn0.75Fe0.25/Al2O3 prepared with ammonia carbamate as precipitating agent...

  13. Susceptibility of pepper weevil (anthonomus eugenii cano) (coleoptera: curculionidae) to seven insecticides in rural areas of Baja California Sur, Mexico


    Rosalía Servín Villegas; José. L. García Hernández; Armando Tejas Romero; José L. Martínez Carrillo; M. A. Toapanta


    The susceptibility of the pepper weevil (Anthonomus eugenii), collected from Baja California Sur, Mexico, to seven insecticides was determined. Acontact, residual exposition method was used to obtain the lethal concentrations fifty (LC50) and the diagnostic concentration (LC95) of organophosphates (OF), carbamates (CA), pyrethroids (PIR), and organochlorine (OC) insecticides used to control pepper weevils from two agricultural areas (Los Planes and Todos Santos) in Southern Baja California Pe...

  14. Insecticide susceptibility of Aedes aegypti populations from Senegal and Cape Verde Archipelago


    Dia Ibrahima; Diagne Cheikh; Ba Yamar; Diallo Diawo; Konate Lassana; Diallo Mawlouth


    Abstract Background Two concomitant dengue 3 (DEN-3) epidemics occurred in Cape Verde Archipelago and Senegal between September and October 2009. Aedes aegypti was identified as the vector of these epidemics as several DEN-3 virus strains were isolated from this species in both countries. The susceptibility to pyrethroids, organochlorine, organophosphates and carbamate was investigated in two field strains of Aedes aegypti from both countries using WHO diagnostic bioassay kits in order to mon...

  15. Uso de pesticidas para el cultivo de algodón. Situación actual.



    The paper reviews the world production of cotton and the use of pesticides in its growth. The risks derived from their abuse, especially chlorinated ones, are commented. Organophosphorous pesticides and carbamates have a wider spectrum of activity and less environmental persistence, although their are more toxic for mammalian beings. Since the 70th, the «piretrinas» have solved some of the problems derived from pets with resistance to the above mentioned two pesticides. Nevertheless, utilizat...

  16. Characterization of the Pseudomonas pseudoalcaligenes CECT5344 Cyanase, an Enzyme That Is Not Essential for Cyanide Assimilation▿


    Luque-Almagro, Víctor M.; Huertas, María-J.; Sáez, Lara P.; Luque-Romero, Manuel Martínez; Moreno-Vivián, Conrado; Castillo, Francisco; Roldán, M. Dolores; Blasco, Rafael


    Cyanase catalyzes the decomposition of cyanate into CO2 and ammonium, with carbamate as an unstable intermediate. The cyanase of Pseudomonas pseudoalcaligenes CECT5344 was negatively regulated by ammonium and positively regulated by cyanate, cyanide, and some cyanometallic complexes. Cyanase activity was not detected in cell extracts from cells grown with ammonium, even in the presence of cyanate. Nevertheless, a low level of cyanase activity was detected in nitrogen-starved cells. The cyn ge...

  17. Direct Nucleophilic Substitution of Free Allylic Alcohols in Water Catalyzed by FeCl3⋅6 H2O: Which is the Real Catalyst?


    Trillo Alarcón, María Paz; Baeza, Alejandro; Nájera Domingo, Carmen


    The allylic substitution reaction, and particularly the direct allylic amination reaction, of free allylic alcohols in water catalyzed by FeCl3⋅6 H2O is described. This novel environmentally-friendly methodology allows the use of a wide variety of nitrogenated nucleophiles such as sulfonamides, carbamates, benzamides, anilines, benzotriazoles, and azides, generally giving good yields of the corresponding substitution products. The synthetic applicability of the process is also demonstrated be...

  18. Improving the developability profile of pyrrolidine progesterone receptor partial agonists

    Energy Technology Data Exchange (ETDEWEB)

    Kallander, Lara S.; Washburn, David G.; Hoang, Tram H.; Frazee, James S.; Stoy, Patrick; Johnson, Latisha; Lu, Qing; Hammond, Marlys; Barton, Linda S.; Patterson, Jaclyn R.; Azzarano, Leonard M.; Nagilla, Rakesh; Madauss, Kevin P.; Williams, Shawn P.; Stewart, Eugene L.; Duraiswami, Chaya; Grygielko, Eugene T.; Xu, Xiaoping; Laping, Nicholas J.; Bray, Jeffrey D.; Thompson, Scott K. (GSKPA)


    The previously reported pyrrolidine class of progesterone receptor partial agonists demonstrated excellent potency but suffered from serious liabilities including hERG blockade and high volume of distribution in the rat. The basic pyrrolidine amine was intentionally converted to a sulfonamide, carbamate, or amide to address these liabilities. The evaluation of the degree of partial agonism for these non-basic pyrrolidine derivatives and demonstration of their efficacy in an in vivo model of endometriosis is disclosed herein.

  19. Synthesis and Evaluation of Novel RSK Inhibitors in a Living Human Breast Model (United States)


    activity in all the lines.1,5,9 Thus it appears that some cancer cells have become addicted to RSK, which suggests that RSK may be a potential new... carbohydrate portions of the natural product. In the course of this work we discovered that the 300 and 400 acetyl groups of the carbohydrate are critical...carbamate modification should render an analog suitable for in vivo evaluation. In summary, the C300 and C400 acetates on the carbohydrate moi- ety of

  20. Airfield Damage Repair (ADR); Polymer Repair of Airfields Summary of Research (United States)


    cured polyurethane has its advantages and disadvantages. A disadvantage to using water as a catalyst is that moisture in the air can trigger...SET® XII 2000 Aromatic Polyurethane (PUB2) Ashland PEP SET® 3501 Phenolic Urethane Catalyst (PUC1) Ashland PEP SET® 3325 Phenolic Urethane Catalyst ...water in one-component polyurethanes . The product is unstable carbamic acid, which splits into carbon dioxide and an amine . The amine then reacts

  1. Influence of phenolic compounds on the growth and arginine deiminase system in a wine lactic acid bacterium


    Alberto, María R.; Manca de Nadra,María C.; Arena, Mario E.


    The influence of seven phenolic compounds, normally present in wine, on the growth and arginine deiminase system (ADI) of Lactobacillus hilgardii X1B, a wine lactic acid bacterium, was established. This system provides energy for bacterial growth and produces citrulline that reacts with ethanol forming the carcinogen ethyl carbamate (EC), found in some wines. The influence of phenolic compounds on bacterial growth was compound dependent. Growth and final pH values increased in presence of arg...

  2. Occurrence of Arginine Deiminase Pathway Enzymes in Arginine Catabolism by Wine Lactic Acid Bacteria


    Liu., S; Pritchard, G. G.; Hardman, M. J.; Pilone, G. J.


    l-Arginine, an amino acid found in significant quantities in grape juice and wine, is known to be catabolized by some wine lactic acid bacteria. The correlation between the occurrence of arginine deiminase pathway enzymes and the ability to catabolize arginine was examined in this study. The activities of the three arginine deiminase pathway enzymes, arginine deiminase, ornithine transcarbamylase, and carbamate kinase, were measured in cell extracts of 35 strains of wine lactic acid bacteria....

  3. Differentiated NSC-34 cells as an in vitro Cell Model for VX (United States)


    June 2014 Published online 11 September 2014 Introduction The organophosphate (OP) nerve agents (NA), including soman, sarin, tabun and VX, act...derived BuChE as a stoichiometric bioscavenger for treatment of nerve agent poisoning . Chem Biol Interact 203:160–6. Sundstrom L, Morrison B III, Bradley...for the sensitive detection of organophosphate pesticides, carbamates and nerve agents. Biosens Bioelectron 25:832–8. Zhang Y, Bhavnani BR. (2006

  4. Diet Restriction and Fasting Exacerbate the Toxicity of Soman in Young and Old Guinea Pigs (United States)


    1985;5:S29-S38. Gordon JJ, Leadbeater L, Maidment MP. The protection of animals against organophosphate poisoning by pretreatment with a carbamate...soman. Drug Chem Toxicol 2004;27:95-110. Clement JG. Effect of fasting on the acute toxicity of HI-6 and its efficacy in soman poisoned mice. Fundam... poisoning in the guinea-pig. J Pharm Pharmacol 1983;35:427-33. Jovic RC. Correlation between signs of toxicity and some biochemical changes in rats poisoned

  5. A Common Mechanism for Resistance to Oxime Reactivation of Acetylcholinesterase Inhibited by Organophosphorus Compounds (United States)


    Organophosphates and Carbamates, Butterworth & Heinemann, Oxford, 1992. pp. 555–577. [2] P. Taylor, Anticholinesterase agents, in: L.L. Brunton, J.S...agent poisoning by in vitro analysis, Toxicol. Appl. Pharmacol. 219 (2007) 226–234. [7] A. Ashani, Z. Radic, I. Tsigelny, D.C. Vellom, N.A. Pickering... organophosphate -inhibited fetal bovine serum acetylcholinesterase by monoquaternary and bisquaternary ligands, Mol. Pharmacol. 55 (1998) 718– 726. [19] Z. Kovarik

  6. The Anticholinergic and Antiglutamatergic Drug Caramiphen Reduces Seizure Duration in Soman-Exposed Rats: Synergism with the Benzodiazepine Diazepam (United States)


    organophosphate poisoning by pretreatment with a carbamate. Toxicol. Appl. Pharmacol. 43, 207–216. Gordon, R.K., Haigh, J.R., Garcia, G.E., Feaster, S.R...value of gacyclidine (GK-11) as adjuvant medication to conventional treatments of organophosphate poisoning : primate experiments mimicking various...Raveh, L., 2008. Therapy against organophosphate poisoning : the impor- tance of anticholinergic drugs with antiglutamatergic properties. Toxicol. Appl

  7. Phenyl N-(2-methylphenylcarbamate

    Directory of Open Access Journals (Sweden)

    Durre Shahwar


    Full Text Available In the title compound, C14H13NO2, the aromatic rings attached to the O and N atoms make dihedral angles of 62.65 (9 and 38.28 (11°, respectively, with the central carbamate group. The benzene rings are oriented at a dihedral angle of 39.22 (10°. In the crystal, a very weak C—H...π interaction occurs.

  8. Synthesis and antibacterial activity of 4“-O-carbamoyl analogs of clarithromycin

    Institute of Scientific and Technical Information of China (English)


    A series of novel 4"-O-carbamoyl analogs of clarithromycin were synthesized and evaluated for their in vitro antibacterial activity. All of the desired compounds showed excellent activity against erythromycin-susceptible S.pneumoniae.Particularly,4-fluorobenzyl carbamate 7a demonstrated potent activity against erythromycin-resistant S.pneumoniae encoded by the mef gene,and remarkably improved activity against erythromycin-resistant S.pneumoniae encoded by the erm gene,and the erm and mef genes.

  9. Exposure of nonbreeding migratory shorebirds to cholinesterase-inhibiting contaminants in the western hemisphere (United States)

    Strum, K.M.; Hooper, M.J.; Johnson, K.A.; Lanctot, Richard B.; Zaccagnini, M.E.; Sandercock, B.K.


    Migratory shorebirds frequently forage and roost in agricultural habitats, where they may be exposed to cholinesterase-inhibiting pesticides. Exposure to organophosphorus and carbamate compounds, common anti-cholinesterases, can cause sublethal effects, even death. To evaluate exposure of migratory shorebirds to organophosphorus and carbamates, we sampled birds stopping over during migration in North America and wintering in South America. We compared plasma cholinesterase activities and body masses of individuals captured at sites with no known sources of organophosphorus or carbamates to those captured in agricultural areas where agrochemicals were recommended for control of crop pests. In South America, plasma acetylcholinesterase and butyrylcholinesterase activity in Buff-breasted Sandpipers was lower at agricultural sites than at reference sites, indicating exposure to organophosphorus and carbamates. Results of plasma cholinesterase reactivation assays and foot-wash analyses were inconclusive. A meta-analysis of six species revealed no widespread effect of agricultural chemicals on cholinesterase activity. however, four of six species were negative for acetylcholinesterase and one of six for butyrylcholinesterase, indicating negative effects of pesticides on cholinesterase activity in a subset of shorebirds. Exposure to cholinesterase inhibitors can decrease body mass, but comparisons between treatments and hemispheres suggest that agrochemicals did not affect migratory shorebirds' body mass. Our study, one of the first to estimate of shorebirds' exposure to cholinesterase-inhibiting pesticides, suggests that shorebirds are being exposed to cholinesterase- inhibiting pesticides at specific sites in the winter range but not at migratory stopover sites. future research should examine potential behavioral effects of exposure and identify other potential sitesand levels of exposure. ?? The Cooper Ornithological Society 2010.

  10. A simple and expedient method for the stepwise synthesis of 2-ethoxy-(4H)-3,1-benzoxazine-4-ones

    Institute of Scientific and Technical Information of China (English)

    Asrin Bahmani; Mahnaz Sharafi-Kolkeshvandi; Farzad Nikpour


    A simple and practical route is described for the synthesis of 2-ethoxy-(4H)-3,1-benzoxazine-4-ones using the coupling reaction of anthranilic acid derivatives with diethyl dicarbonate following with fast cyclization of the carbamate adduct with a dehydrocyclization agent such as cyanuric chloride and N,N'-dicyclohexylcarbodiimide in PEG at room temperature.High yields of the products obtained under mild reaction conditions with simple work-up of the reaction mixture.

  11. Comparison of Current-Use Pesticide and Other Toxicant Urinary Metabolite Levels among Pregnant Women in the CHAMACOS Cohort and NHANES



    Background We measured 34 metabolites of current-use pesticides and other precursor compounds in urine samples collected twice during pregnancy from 538 women living in the Salinas Valley of California, a highly agricultural area (1999–2001). Precursors of these metabolites included fungicides, carbamate, organochlorine, organophosphorus (OP), and pyrethroid insecticides, and triazine and chloroacetanilide herbicides. We also measured ethylenethiourea, a metabolite of the ethylene-bisdithioca...

  12. Synthetic Organic Electrochemistry in Ionic Liquids: The Viscosity Question


    Handy, Scott T.; Steven Bornemann


    Ionic liquids are obvious candidates for use in electrochemical applications due to their ionic character. Nevertheless, relatively little has been done to explore their application in electrosynthesis. We have studied the Shono oxidation of arylamines and carbamates using ionic liquids as recyclable solvents and have noted that the viscosity of the medium is a major problem, although with the addition of sufficient co-solvent, good results and excellent recovery and recycling of the ionic li...


    Institute of Scientific and Technical Information of China (English)


    Synthetic pyrethroids are considered as possible sub-stitutesfor some organophosphate carbamates or organochlo-rine insecticides,and have been used extensivelyfor morethantwo decades[1].Pyrethroids are preferred over otherinsecticides because of their easy degradation into non-toxic or less toxic metabolites under natural conditions.Consequently,there has recently beena dramatic increaseinthe use of pyrethroid pesticides to control insect pests.However,synthetic pyrethroids were also reported to bemore toxi...

  14. Development of acetylcholinesterase biosensors for neurotoxins detection in foods and the environment


    Roepcke, Clarisse Brüning Schmitt


    Acetylcholinesterase (AChE) is responsible for the hydrolysis of acetylcholine in the nervous system. It is inhibited by several substances, like organophosphate and carbamate insecticides, glycoalkaloids, nerve gas and anatoxin-a(s). There is a growing need to develop new technologies to reduce time spent with sample preparation, discriminate between positive and negative samples, and to reduce analysis costs. Over the last decades, AChE biosensors have emerged as an ultra sensitive and rapi...

  15. A rapid and specific derivatization procedure to identify acyl-glucuronides by mass spectrometry. (United States)

    Vaz, Alfin D N; Wang, Wei Wei; Bessire, Andrew J; Sharma, Raman; Hagen, Anne E


    A simple procedure is described to identify acyl-glucuronides by coupled liquid chromatography/mass spectrometry after derivatization to a hydroxamic acid with hydroxylamine. The reaction specificity obviates the need for isolation of the acyl-glucuronide from an extract. Glucuronides derived from carbamic acids, and alkyl- and aromatic amines, are inert to the derivatization reaction conditions, making the hydroxamic acid derivative a fingerprint for acyl-glucuronides.

  16. Determination of trace amounts of selenium in minerals and rocks by flame less atomic-absorption spectrometry; Determinacion de selinio en minerales y rocas por espectrometria de absorcion atomica

    Energy Technology Data Exchange (ETDEWEB)

    Alduan, F. A.; Capdevilla, C.


    The determination of trace amounts of selenium In silicate rocks and feldspar by solvent extraction and graphite furnace atomic-absorption spectrometry has been stu- died. Sodium diethyl-ditio carbamate and ammonium pyrrolidine dithiocarbamate have been tried as chelating agents. The best results are achieved when selenium is extracted Into carbon tetrachloride as the sodium diethyldithiocarbamate complex. The method allows to detect 0,75 ppm of selenium in the sample. Recoveries are about 100%. (Author) 7 refs.

  17. B-type esterases in the snail Xeropicta derbentina: An enzymological analysis to evaluate their use as biomarkers of pesticide exposure

    Energy Technology Data Exchange (ETDEWEB)

    Laguerre, Christel [Universite d' Avignon et des Pays de Vaucluse, UMR 406 UAPV/INRA, F-84914 Avignon (France); INRA, Laboratoire de Toxicologie Environnementale, UMR 406 UAPV/INRA, F-84914 Avignon (France); Sanchez-Hernandez, Juan C. [Laboratory of Ecotoxicology, Faculty of Environmental Science, University of Castilla-La Mancha, Avda. Carlos III s/n, 45071 Toledo (Spain); Koehler, Heinz R. [Animal Physiological Ecology, University of Tuebingen, Konrad-Adenauer-Strasse 20, D-72072 Tuebingen (Germany); Triebskorn, Rita [Animal Physiological Ecology, University of Tuebingen, Konrad-Adenauer-Strasse 20, D-72072 Tuebingen (Germany); Steinbeis-Transfer Center for Ecotoxicology and Ecophysiology, Blumenstrasse 13, D-72108 Rottenburg (Germany); Capowiez, Yvan [INRA, Unite PSH, F- 84914 Avignon (France); Rault, Magali [Universite d' Avignon et des Pays de Vaucluse, UMR 406 UAPV/INRA, F-84914 Avignon (France); INRA, Laboratoire de Toxicologie Environnementale, UMR 406 UAPV/INRA, F-84914 Avignon (France); Mazzia, Christophe [Universite d' Avignon et des Pays de Vaucluse, UMR 406 UAPV/INRA, F-84914 Avignon (France); INRA, Laboratoire de Toxicologie Environnementale, UMR 406 UAPV/INRA, F-84914 Avignon (France)], E-mail:


    The study was prompted to characterize the B-type esterase activities in the terrestrial snail Xeropicta derbentina and to evaluate its sensitivity to organophosphorus and carbamate pesticides. Specific cholinesterase and carboxylesterase activities were mainly obtained with acetylthiocholine (K{sub m} = 77.2 mM; V{sub max} = 38.2 mU/mg protein) and 1-naphthyl acetate (K{sub m} = 222 mM, V{sub max} = 1095 mU/mg protein) substrates, respectively. Acetylcholinesterase activity was concentration-dependently inhibited by chlorpyrifos-oxon, dichlorvos, carbaryl and carbofuran (IC50 = 1.35 x 10{sup -5}-3.80 x 10{sup -8} M). The organophosphate-inhibited acetylcholinesterase activity was reactivated in the presence of pyridine-2-aldoxime methochloride. Carboxylesterase activity was inhibited by organophosphorus insecticides (IC50 = 1.20 x 10{sup -5}-2.98 x 10{sup -8} M) but not by carbamates. B-esterase-specific differences in the inhibition by organophosphates and carbamates are discussed with respect to the buffering capacity of the carboxylesterase to reduce pesticide toxicity. These results suggest that B-type esterases in X. derbentina are suitable biomarkers of pesticide exposure and that this snail could be used as sentinel species in field monitoring of Mediterranean climate regions. - Characterization of the B-type esterases in the terrestrial snail Xeropicta derbentina in order to evaluate pesticide exposure.

  18. Cyclobutane Synthesis and Fragmentation. A Cascade Route to the Lycopodium Alkaloid (-)-Huperzine A. (United States)

    White, James D; Li, Yang; Kim, Jungchul; Terinek, Miroslav


    An asymmetric total synthesis of the nootropic alkaloid (-)-huperzine A was completed using a cascade sequence initiated by an intramolecular aza-Prins reaction and terminated by a stereoelectronically guided fragmentation of a cyclobutylcarbinyl cation as the key step in assembling the bicyclo[3.3.1]nonene core of the natural product. Intramolecular [2 + 2]-photocycloaddition of the crotyl ether of (S)-4-hydroxycyclohex-2-enone afforded a bicyclo[4.2.0]octanone containing an embedded tetrahydrofuran in which the cyclohexanone moiety was converted to a triisopropylsilyl enol ether and functionalized as an allylic azide. The derived primary amine was acylated with α-phenylselenylacrylic acid, and the resulting amide was reacted with trimethylaluminum to give a [2 + 2]-cycloadduct, which underwent retroaldol fission to produce a fused α-phenylselenyl δ-lactam. Periodate oxidation of this lactam led directly to an α-pyridone, which was converted to a fused 2-methoxypyridine. Reductive cleavage of the activated "pyridylic" C-O bond in this tetracycle and elaboration of the resultant hydroxy ketone to a diketone was followed by chemoselective conversion of the methyl ketone in this structure to an endo isopropenyl group. Condensation of the remaining ketone with methyl carbamate in the presence of acid initiated the programmed cascade sequence and furnished a known synthetic precursor to huperzine A. Subsequent demethylation of the carbamate and the methoxypyridine, accompanied by in situ decarboxylation of the intermediate carbamic acid, gave (-)-huperzine A.

  19. Design and synthesis of biotin analogues reversibly binding with streptavidin. (United States)

    Yamamoto, Tomohiro; Aoki, Kiyoshi; Sugiyama, Akira; Doi, Hirofumi; Kodama, Tatsuhiko; Shimizu, Yohei; Kanai, Motomu


    Two new biotin analogues, biotin carbonate 5 and biotin carbamate 6, have been synthesized. These molecules were designed to reversibly bind with streptavidin by replacing the hydrogen-bond donor NH group(s) of biotin's cyclic urea moiety with oxygen. Biotin carbonate 5 was synthesized from L-arabinose (7), which furnishes the desired stereochemistry at the 3,4-cis-dihydroxy groups, in 11% overall yield (over 10 steps). Synthesis of biotin carbamate 6 was accomplished from L-cysteine-derived chiral aldehyde 33 in 11% overall yield (over 7 steps). Surface plasmon resonance analysis of water-soluble biotin carbonate analogue 46 and biotin carbamate analogue 47 revealed that KD values of these compounds for binding to streptavidin were 6.7×10(-6)  M and 1.7×10(-10)  M, respectively. These values were remarkably greater than that of biotin (KD =10(-15)  M), and thus indicate the importance of the nitrogen atoms for the strong binding between biotin and streptavidin.

  20. Mutagenic studies on the effect of Aldicarb "Temik" and vitamin C as antioxidant agent on the white rat:(Chromosomal aberrations and Micronucleus tests

    Directory of Open Access Journals (Sweden)

    Fatma M. Hamam* and Ihab H. Foda


    Full Text Available Widespread contamination of the environment due to increased and frequently indiscriminate usage of insecticides during the last two decades has aroused much concern over the possibility of their radiominetic effect. Evidence accumulating over the years emphasized the indisputable link between certain insecticides, chromosomal damage and possibility of gene mutation. There is a wide variety of insecticides, among which the carbamates. Their chemical relationship to ethyl carbamate makes them worthy of study for their possible deleterious effect on biological system. The main object of the present study is to evaluate the mutagenic effect of a carbamate insecticide" Aldicarb" alone and in combination of vitamin C as an antioxidant agent to decrease their mutagenicity. Male albino rats were tested orally for 48 hours , two doses of aldicarb were used in absence and in the presence of viamin C (1/4 and 1/10 LD50. The obtained data showed highly significant increase in the micronucleus (PCEM and in chromosomal aberrations in rat bone marrow cells at the two doses of aldicarb compared to control group. (P< 0.0001. The frequency of chromosomal aberrations and micronucleus decreased in rats treated with aldicarb and vitamin C than in aldicarb treated group. From these results we concluded that cytogenetic effect of aldicarb might be decreased by the usage of vitamin as an antioxidant agent.

  1. New Atglistatin closely related analogues: Synthesis and structure-activity relationship towards adipose triglyceride lipase inhibition. (United States)

    Roy, Pierre-Philippe; D'Souza, Kenneth; Cuperlovic-Culf, Miroslava; Kienesberger, Petra C; Touaibia, Mohamed


    Adipose Triglyceride Lipase (ATGL) performs the first and rate-limiting step in lipolysis by hydrolyzing triacylglycerols stored in lipid droplets to diacylglycerols. By mediating lipolysis in adipose and non-adipose tissues, ATGL is a major regulator of overall energy metabolism and plasma lipid levels. Since chronically high levels of plasma lipids are linked to metabolic disorders including insulin resistance and type 2 diabetes, ATGL is an interesting therapeutic target. In the present study, fourteen closely related analogues of Atglistatin (1), a newly discovered ATGL inhibitor, were synthesized, and their ATGL inhibitory activity was evaluated. The effect of these analogues on lipolysis in 3T3-L1 adipocytes clearly shows that inhibition of the enzyme by Atglistatin (1) is due to the presence of the carbamate and N,N-dimethyl moieties on the biaryl central core at meta and para position, respectively. Mono carbamate-substituted analogue C2, in which the carbamate group was in the meta position as in Atglistatin (1), showed slight inhibition. Low dipole moment of Atglistatin (1) compared to the synthesized analogues possibly explains the lower inhibitory activities.

  2. Validating the importance of two acetylcholinesterases in insecticide sensitivities by RNAi in Pardosa pseudoannulata, an important predatory enemy against several insect pests. (United States)

    Meng, Xiangkun; Li, Chunrui; Bao, Haibo; Fang, Jichao; Liu, Zewen; Zhang, Yixi


    The pond wolf spider (Pardosa pseudoannulata) is an important predatory enemy against several insect pests and showed relative different sensitivities to organophosphate and carbamate insecticides compared to insect pests. In our previous studies, two acetylcholinesterases were identified in P. pseudoannulata and played important roles in insecticide sensitivities. In order to understand the contributions of the two acetylcholinesterases to insecticide sensitivities, we firstly employed the RNAi technology in the spider. For a suitable microinjection RNAi method, the injection site, injection volume and interference time were optimized, which then demonstrated that the injection RNAi method was applicable in this spider. With the new RNAi method, it was revealed that both Pp-AChE1 and Pp-AChE2, encoded by genes Ppace1 and Ppace2, were the targets of organophosphate insecticides, but Pp-AChE1 would be more important. In contrast, the carbamate acted selectively on Pp-AChE1. The results showed that Pp-AChE1 was the major catalytic enzyme in P. pseudoannulata and the major target of organophosphate and carbamate insecticides. In a word, an RNAi method was established in the pond wolf spider, which further validated the importance of two acetylcholinesterases in insecticide sensitivities in this spider.

  3. Mechanistic Insights into the Organopolymerization of N-Methyl N-Carboxyanhydrides Mediated by N-Heterocyclic Carbenes

    KAUST Repository

    Falivene, Laura


    We report on a DFT investigation of initiation, propagation, and termination in the organopolymerization of N-methyl N-carboxyanhydrides toward cyclic poly(N-substituted glycine)s, promoted by N-heterocyclic carbenes (NHC). Calculations support the experimentally based hypothesis of two competing initiation pathways. The first leading to formation of a zwitterionic adduct by nucleophilic addition of the NHC to one of the carbonyl groups of monomer. The second via acid–base reactivity, starting with the NHC promoted abstraction of a proton from the methylene group of the monomer, leading to an ion-pair-type adduct, followed by nucleophilic attack of the adduct to a new monomer molecule. Chain elongation can proceed from both the initiation adducts via nucleophilic attack of the carbamate chain-end to a new monomer molecule via concerted elimination of CO2 from the carbamate chain-end. Energy barriers along all the considered termination pathways are remarkably higher that the energy barrier along the chain elongation pathways, consistent with the quasi-living experimental behavior. Analysis of the competing termination pathways suggests that the cyclic species determined via MALDI-TOF MS experiments consists of a zwitterionic species deriving from nucleophilic attack of the N atom of the carbamate chain-end to the C═O group bound to the NHC moiety.

  4. Superfamily-wide portrait of serine hydrolase inhibition achieved by library-versus-library screening. (United States)

    Bachovchin, Daniel A; Ji, Tianyang; Li, Weiwei; Simon, Gabriel M; Blankman, Jacqueline L; Adibekian, Alexander; Hoover, Heather; Niessen, Sherry; Cravatt, Benjamin F


    Serine hydrolases (SHs) are one of the largest and most diverse enzyme classes in mammals. They play fundamental roles in virtually all physiological processes and are targeted by drugs to treat diseases such as diabetes, obesity, and neurodegenerative disorders. Despite this, we lack biological understanding for most of the 110+ predicted mammalian metabolic SHs, in large part because of a dearth of assays to assess their biochemical activities and a lack of selective inhibitors to probe their function in living systems. We show here that the vast majority (> 80%) of mammalian metabolic SHs can be labeled in proteomes by a single, active site-directed fluorophosphonate probe. We exploit this universal activity-based assay in a library-versus-library format to screen 70+ SHs against 140+ structurally diverse carbamates. Lead inhibitors were discovered for ∼40% of the screened enzymes, including many poorly characterized SHs. Global profiles identified carbamate inhibitors that discriminate among highly sequence-related SHs and, conversely, enzymes that share inhibitor sensitivity profiles despite lacking sequence homology. These findings indicate that sequence relatedness is not a strong predictor of shared pharmacology within the SH superfamily. Finally, we show that lead carbamate inhibitors can be optimized into pharmacological probes that inactivate individual SHs with high specificity in vivo.

  5. Cationic poly(ɛ-caprolactone) surface functionalized mesoporous silica nanoparticles and their application in drug delivery (United States)

    Zhang, Yan; Wang, Zhaojun; Zhou, Weimin; Min, Guoquan; Lang, Meidong


    Cationic poly(ɛ-caprolactone) modified hollow mesoporous silica (HMSNs) was achieved by a post graft method via covalent linkage between the silanols on the surface of silica and the trimethoxysilane groups at the end of the poly(γ-(carbamic acid benzyl ester)-ɛ-caprolactone). The trimethoxysilane groups were introduced to poly(γ-(carbamic acid benzyl ester)-ɛ-caprolactone) by ring opening polymerization of γ-(carbamic acid benzyl ester)-ɛ-caprolactone (γCABɛCL) with 3-aminopropyl trimethoxysilane as initiator. Subsequently, the polymer was grafted to the HMSNs and the protected groups of Cbz were removed, thus the amino groups were obtained accordingly. The structure of the polymer was confirmed by 1H NMR. In addition, the TEM and SEM demonstrated that the HMSNs were spherical and the polymer was well coated on the spheres. FTIR, TGA and N2 adsorption results proved that the modified processes were effective and the structure of the HMSNs was well reserved. The cationic surface was further confirmed by zeta potential. Moreover, the potential application of the HMSNs in drug delivery was studied with ammonium glycyrrhizinate (AMG) as model drug. Results showed that the cationic HMSNs could be an efficient AMG carrier.

  6. (13)C and (15)N NMR characterization of amine reactivity and solvent effects in CO2 capture. (United States)

    Perinu, Cristina; Arstad, Bjørnar; Bouzga, Aud M; Jens, Klaus-J


    Factors influencing the reactivity of selected amine absorbents for carbon dioxide (CO2) capture, in terms of the tendency to form amine carbamate, have been studied. Four linear primary alkanolamines at varying chain lengths (MEA, 3A1P, 4A1B , and 5A1P ), two primary amines with different substituents in the β-position to the nitrogen (1A2P and ISOB), a secondary alkanolamine (DEA), and a sterically hindered primary amine (AMP) were investigated. The relationship between the (15)N NMR data of aqueous amines and their ability to form carbamate, as determined at equilibrium by quantitative (13)C NMR experiments, was analyzed, taking into account structural-chemical properties. For all the amines, the (15)N chemical shifts fairly reflected the observed reactivity for carbamate formation. In addition to being a useful tool for the investigation of amine reactivity, (15)N NMR data clearly provided evidence of the importance of solvent effects for the understanding of chemical dynamics in CO2 capture by aqueous amine absorbents.

  7. Detection of Organophosphorus Pesticides with Colorimetry and Computer Image Analysis. (United States)

    Li, Yanjie; Hou, Changjun; Lei, Jincan; Deng, Bo; Huang, Jing; Yang, Mei


    Organophosphorus pesticides (OPs) represent a very important class of pesticides that are widely used in agriculture because of their relatively high-performance and moderate environmental persistence, hence the sensitive and specific detection of OPs is highly significant. Based on the inhibitory effect of acetylcholinesterase (AChE) induced by inhibitors, including OPs and carbamates, a colorimetric analysis was used for detection of OPs with computer image analysis of color density in CMYK (cyan, magenta, yellow and black) color space and non-linear modeling. The results showed that there was a gradually weakened trend of yellow intensity with the increase of the concentration of dichlorvos. The quantitative analysis of dichlorvos was achieved by Artificial Neural Network (ANN) modeling, and the results showed that the established model had a good predictive ability between training sets and predictive sets. Real cabbage samples containing dichlorvos were detected by colorimetry and gas chromatography (GC), respectively. The results showed that there was no significant difference between colorimetry and GC (P > 0.05). The experiments of accuracy, precision and repeatability revealed good performance for detection of OPs. AChE can also be inhibited by carbamates, and therefore this method has potential applications in real samples for OPs and carbamates because of high selectivity and sensitivity.

  8. Propoxur: a novel mechanism for insecticidal action and toxicity. (United States)

    Kovacic, Peter; Somanathan, Ratnasamy


    Propoxur is a carbamate insecticide that has recently attracted considerable attention as a possible treatment option for addressing the bedbug epidemic. The generally accepted mechanism of toxicity for propoxur involves the inhibition of ChE, as is the case for many agents in the category. Considerable research supports the concept that most physiologically active substances induce their effects through multi-faceted action. In this review, we provide evidence that ET--ROS--OS participate mechanistically in both the action and in human toxicity of pesticides, including propoxur. Propoxur is a catechol derivative that contains carbamate and isopropyl groups on the oxygens in its moiety. Metabolic studies with propoxur reveal hydrolysis of the carbamate and dealkylation of the isopropyl group to yield the parent catechol. In addition, nuclear hydroxylation produces a hydroquinone derivative. Both the catechol and this hydroquinone derivative are potentially able to undergo redox cycling with the corresponding quinone to produce ROS. It is primarily for these reasons that we believe propoxur may be similar to other classes of physiologically active compounds in producing effects through ET-ROS-OS. Generally, reactive ROS are generated by metabolic processes that yield ET entities, and this occurs with propoxur as well. Although ROS are commonly associated with toxicity, there is little recognition in the literature that they can also play a role in therapeutic action.

  9. Isomorphous Crystals from Diynes and Bromodiynes Involved in Hydrogen and Halogen Bonds

    Directory of Open Access Journals (Sweden)

    Pierre Baillargeon


    Full Text Available Isomorphous crystals of two diacetylene derivatives with carbamate functionality (BocNH-CH2-diyne-X, where X = H or Br have been obtained. The main feature of these structures is the original 2D arrangement (as supramolecular sheets or walls in which the H bond and halogen bond have a prominent effect on the whole architecture. The two diacetylene compounds harbor neighboring carbamate (Boc protected amine and conjugated alkyne functionalities. They differ only by the nature of the atom located at the penultimate position of the diyne moiety, either a hydrogen atom or a bromine atom. Both of them adopt very similar 2D wall organizations with antiparallel carbamates (as in antiparallel beta pleated sheets. Additional weak interactions inside the same walls between molecular bricks are H bond interactions (diyne-H···O=C or halogen bond interactions (diyne-Br···O=C, respectively. Based on crystallographic atom coordinates, DFT (B3LYP/6-31++G(d,p and DFT (M06-2X/6-31++G(d,p calculations were performed on these isostructural crystals to gain insight into the intermolecular interactions.

  10. Fluensulfone is a nematicide with a mode of action distinct from anticholinesterases and macrocyclic lactones. (United States)

    Kearn, James; Ludlow, Elizabeth; Dillon, James; O'Connor, Vincent; Holden-Dye, Lindy


    Plant parasitic nematodes infest crops and present a threat to food security worldwide. Currently available chemical controls e.g. methyl bromide, organophosphates and carbamates have an unacceptable level of toxicity to non-target organisms and are being withdrawn from use. Fluensulfone is a new nematicide of the fluoroalkenyl thioether group that has significantly reduced environmental impact with low toxicity to non-target insects and mammals. Here, we show that the model genetic organism Caenorhabditis elegans is susceptible to the irreversible nematicidal effects of fluensulfone. Whilst the dose required is higher than that which has nematicidal activity against Meloidogyne spp. the profile of effects on motility, egg-hatching and survival is similar to that reported for plant parasitic nematodes. C. elegans thus provides a tractable experimental paradigm to analyse the effects of fluensulfone on nematode behaviour. We find that fluensulfone has pleiotropic actions and inhibits development, egg-laying, egg-hatching, feeding and locomotion. In the case of feeding and locomotion, an early excitation precedes the gross inhibition. The profile of these effects is notably distinct from other classes of anthelmintic and nematicide: the inhibition of motility caused by fluensulfone is not accompanied by the hypercontraction which is characteristic of organophosphates and carbamates and C. elegans mutants that are resistant to the carbamate aldicarb and the macrocyclic lactone ivermectin retain susceptibility to fluensulfone. These data indicate fluensulfone's mode of action is distinct from currently available nematicides and it therefore presents a promising new chemical entity for crop protection.

  11. Carbon dioxide: A substitute for phosgene

    Energy Technology Data Exchange (ETDEWEB)

    Aresta, M.; Quaranta, E. [Univ. of Bari (Italy)


    One of the many goals of the green chemistry movement is to eliminate the use of phosgene (COCl{sub 2}), an extremely hazardous compound used in many syntheses, including the production of carbamates, organic carbonates, and polymers. One of the most interesting options for eliminating this compound is to replace it with CO{sub 2}. In addition to carbon dioxide`s abundance and benign nature, it has the benefits of recycling carbon and of reducing the amount of CO{sub 2} released into the atmosphere when its use is linked with other processes that emit CO{sub 2}. Several synthetic strategies that do not use phosgene are under development. The authors briefly review the most interesting ones and then expand on the use of CO{sub 2} as a potential building block for organic carbamates, carbonates, and isocyanates. One of these routes, polycarbonate synthesis, is already in industrial-scale operation: PAC Polymers Inc. currently produces CO{sub 2}-epoxide copolymers. The synthesis of carbamates and substituted ureas has been developed, and this process awaits industrial exploitation.

  12. CYP6 P450 enzymes and ACE-1 duplication produce extreme and multiple insecticide resistance in the malaria mosquito Anopheles gambiae.

    Directory of Open Access Journals (Sweden)

    Constant V Edi


    Full Text Available Malaria control relies heavily on pyrethroid insecticides, to which susceptibility is declining in Anopheles mosquitoes. To combat pyrethroid resistance, application of alternative insecticides is advocated for indoor residual spraying (IRS, and carbamates are increasingly important. Emergence of a very strong carbamate resistance phenotype in Anopheles gambiae from Tiassalé, Côte d'Ivoire, West Africa, is therefore a potentially major operational challenge, particularly because these malaria vectors now exhibit resistance to multiple insecticide classes. We investigated the genetic basis of resistance to the most commonly-applied carbamate, bendiocarb, in An. gambiae from Tiassalé. Geographically-replicated whole genome microarray experiments identified elevated P450 enzyme expression as associated with bendiocarb resistance, most notably genes from the CYP6 subfamily. P450s were further implicated in resistance phenotypes by induction of significantly elevated mortality to bendiocarb by the synergist piperonyl butoxide (PBO, which also enhanced the action of pyrethroids and an organophosphate. CYP6P3 and especially CYP6M2 produced bendiocarb resistance via transgenic expression in Drosophila in addition to pyrethroid resistance for both genes, and DDT resistance for CYP6M2 expression. CYP6M2 can thus cause resistance to three distinct classes of insecticide although the biochemical mechanism for carbamates is unclear because, in contrast to CYP6P3, recombinant CYP6M2 did not metabolise bendiocarb in vitro. Strongly bendiocarb resistant mosquitoes also displayed elevated expression of the acetylcholinesterase ACE-1 gene, arising at least in part from gene duplication, which confers a survival advantage to carriers of additional copies of resistant ACE-1 G119S alleles. Our results are alarming for vector-based malaria control. Extreme carbamate resistance in Tiassalé An. gambiae results from coupling of over-expressed target site allelic

  13. CYP6 P450 enzymes and ACE-1 duplication produce extreme and multiple insecticide resistance in the malaria mosquito Anopheles gambiae. (United States)

    Edi, Constant V; Djogbénou, Luc; Jenkins, Adam M; Regna, Kimberly; Muskavitch, Marc A T; Poupardin, Rodolphe; Jones, Christopher M; Essandoh, John; Kétoh, Guillaume K; Paine, Mark J I; Koudou, Benjamin G; Donnelly, Martin J; Ranson, Hilary; Weetman, David


    Malaria control relies heavily on pyrethroid insecticides, to which susceptibility is declining in Anopheles mosquitoes. To combat pyrethroid resistance, application of alternative insecticides is advocated for indoor residual spraying (IRS), and carbamates are increasingly important. Emergence of a very strong carbamate resistance phenotype in Anopheles gambiae from Tiassalé, Côte d'Ivoire, West Africa, is therefore a potentially major operational challenge, particularly because these malaria vectors now exhibit resistance to multiple insecticide classes. We investigated the genetic basis of resistance to the most commonly-applied carbamate, bendiocarb, in An. gambiae from Tiassalé. Geographically-replicated whole genome microarray experiments identified elevated P450 enzyme expression as associated with bendiocarb resistance, most notably genes from the CYP6 subfamily. P450s were further implicated in resistance phenotypes by induction of significantly elevated mortality to bendiocarb by the synergist piperonyl butoxide (PBO), which also enhanced the action of pyrethroids and an organophosphate. CYP6P3 and especially CYP6M2 produced bendiocarb resistance via transgenic expression in Drosophila in addition to pyrethroid resistance for both genes, and DDT resistance for CYP6M2 expression. CYP6M2 can thus cause resistance to three distinct classes of insecticide although the biochemical mechanism for carbamates is unclear because, in contrast to CYP6P3, recombinant CYP6M2 did not metabolise bendiocarb in vitro. Strongly bendiocarb resistant mosquitoes also displayed elevated expression of the acetylcholinesterase ACE-1 gene, arising at least in part from gene duplication, which confers a survival advantage to carriers of additional copies of resistant ACE-1 G119S alleles. Our results are alarming for vector-based malaria control. Extreme carbamate resistance in Tiassalé An. gambiae results from coupling of over-expressed target site allelic variants with

  14. High level of pyrethroid resistance in an Anopheles funestus population of the Chokwe District in Mozambique.

    Directory of Open Access Journals (Sweden)

    Nelson Cuamba

    Full Text Available BACKGROUND: Although Anopheles funestus is difficult to rear, it is crucial to analyse field populations of this malaria vector in order to successfully characterise mechanisms of insecticide resistance observed in this species in Africa. In this study we carried out a large-scale field collection and rearing of An. funestus from Mozambique in order to analyse its susceptibility status to insecticides and to broadly characterise the main resistance mechanisms involved in natural populations. METHODOLOGY/PRINCIPAL FINDINGS: 3,000 F(1 adults were obtained through larval rearing. WHO susceptibility assays indicated a very high resistance to pyrethroids with no mortality recorded after 1 h 30 min exposure and less than 50% mortality at 3 h 30 min. Resistance to the carbamate, bendiocarb was also noted, with 70% mortality after 1h exposure. In contrast, no DDT resistance was observed, indicating that no kdr-type resistance was involved. The sequencing of the acetylcholinesterase gene indicated the absence of the G119S and F455W mutations associated with carbamate and organophosphate resistance. This could explain the absence of malathion resistance in this population. Both biochemical assays and quantitative PCR implicated up-regulated P450 genes in pyrethroid resistance, with GSTs playing a secondary role. The carbamate resistance observed in this population is probably conferred by the observed altered AChE with esterases also involved. CONCLUSION/SIGNIFICANCE: The high level of pyrethroid resistance in this population despite the cessation of pyrethroid use for IRS in 1999 is a serious concern for resistance management strategies such as rotational use of insecticides. As DDT has now been re-introduced for IRS, susceptibility to DDT needs to be closely monitored to prevent the appearance and spread of resistance to this insecticide.

  15. Development of an analytical strategy based on LC-MS/MS for the measurement of different classes of pesticides and theirs metabolites in meconium: application and characterisation of foetal exposure in France. (United States)

    Berton, Thierry; Mayhoub, Flora; Chardon, Karen; Duca, Radu-Corneliu; Lestremau, Francois; Bach, Véronique; Tack, Karine


    It is important to evaluate the impact of pesticides on human health because exposure to these compounds has been linked to harmful effects in many research studies. This exposure may be particularly harmful during the early stages of development (e.g. the prenatal period). The aim of the present study was to develop an analytical strategy for quantifying a number of pesticides and their metabolites in meconium (the neonate's first faeces), in order to characterize the extent of foetal exposure. The meconium sample was dried and grinded in order to homogenize the sample, prior to solid-liquid extraction and a purification by solid-phase extraction using a weak anion mixed-mode polymeric sorbent. Analyte separation and quantification was performed by liquid chromatography coupled to electrospray-triple quadrupole mass spectrometry. Five pesticide families (carbamates, organophosphates, pyrethroids, phenylureas and phenoxy herbicides) and their metabolites could be quantified in meconium with limits of quantification ranging between 0.2 ng/g and 200 ng/g. This method was applied to a set of 171 meconium samples collected in the Picardie region of northern France. The highest prevalence was observed for metabolites of organophosphates and carbamates (57.9% and 22.8%, respectively). The parent pesticides were rarely present and were only found at very low concentrations, except for the pyrethroids cyfluthrin and cypermethrin, which were found in 7.6% of meconium samples at concentrations of between 43.8 and 480 ng/g. The most frequently detected contaminant was the organophosphate metabolite dimethyl thiophosphate detected in 49.1% of the samples and quantified with a median concentration of 344 ng/g. These data evidence significant foetal exposure to organophosphate pesticides, pyrethroids and carbamates.

  16. Toxicological and biochemical characterizations of AChE in phosalone-susceptible and resistant populations of the common pistachio psyllid, Agonoscena pistaciae. (United States)

    Alizadeh, Ali; Talebi-Jahromi, Khalil; Hosseininaveh, Vahid; Ghadamyari, Mohammad


    The toxicological and biochemical characteristics of acetylcholinesterases (AChE) in nine populations of the common pistachio psyllid, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Psyllidae), were investigated in Kerman Province, Iran. Nine A. pistaciae populations were collected from pistachio orchards, Pistacia vera L. (Sapindales: Anacardiaceae), located in Rafsanjan, Anar, Bam, Kerman, Shahrbabak, Herat, Sirjan, Pariz, and Paghaleh regions of Kerman province. The previous bioassay results showed these populations were susceptible or resistant to phosalone, and the Rafsanjan population was most resistant, with a resistance ratio of 11.3. The specific activity of AChE in the Rafsanjan population was significantly higher than in the susceptible population (Bam). The affinity (K(M)) and hydrolyzing efficiency (Vmax) of AChE on acetylthiocholine iodide, butyrylthiocholine iodide, and propionylthiocholine odide as artificial substrates were clearly lower in the Bam population than that in the Rafsanjan population. These results indicated that the AChE of the Rafsanjan population had lower affinity to these substrates than that of the susceptible population. The higher Vmax value in the Rafsanjan population compared to the susceptible population suggests a possible over expression of AChE in the Rafsanjan population. The in vitro inhibitory effect of several organophosphates and carbamates on AChE of the Rafsanjan and Bam populations was determined. Based on I50, the results showed that the ratios of AChE insensitivity of the resistant to susceptible populations were 23 and 21.7-fold to monocrotophos and phosphamidon, respectively. Whereas, the insensitivity ratios for Rafsanjan population were 0.86, 0.8, 0.78, 0.46, and 0.43 for carbaryl, eserine, propoxur, m-tolyl methyl carbamate, and carbofuran, respectively, suggesting negatively correlated sensitivity to organophosphate-insensitive AChE. Therefore, AChE from the Rafsanjan population showed negatively

  17. Comparison of solid phase- and liquid/liquid-extraction for the purification of hair extract prior to multi-class pesticides analysis. (United States)

    Duca, Radu-Corneliu; Salquebre, Guillaume; Hardy, Emilie; Appenzeller, Brice M R


    The present study focuses on the influence of a purification step - after extraction of pesticides from hair and before analysis of the extract - on the sensitivity of analytical methods including compounds from different chemical classes (both parent and metabolites). Sixty-seven pesticides and metabolites from different chemical classes were tested here: organochlorines, organophosphates, carbamates, pyrethroids, ureas, azoles, phenylpyrazoles and neonicotinoids. Two gas chromatography-negative chemical ionization-tandem mass spectrometry methods and one based on ultra-performance liquid chromatography-electrospray tandem mass spectrometry were used. Seven solid-phase extraction cartridges: C18, S-DVB, PS-DVB, GCB, GCB/PSA, SAX/PSA and Florisil/PSA were tested and compared to more classical liquid-liquid extraction procedures using ethyl acetate, hexane and dichloromethane. Although LLE allowed obtaining good results for some compounds, on the whole, SPE clearly provided better recovery for the majority of the pesticide residues tested in the present study. GCB/PSA was clearly the best suited to non-polar compounds such as organochlorines, pyrethroids and organophosphates, with recovery ranging from 45.9% (diflufenican) to 117.1% (parathion methyl). For hydrophilic metabolites (e.g. dialkyl phosphates and other organophosphate metabolites, pyrethroid metabolites, phenols and carbamate metabolites), the best results were obtained with PS-DVB, with recovery ranged from 10.3% (malathion monocarboxylic acid) to 93.1% (para-nitrophenol). For hydrophilic parent pesticides (e.g. neonicotinoids, carbamates, azoles) and metabolites without nucleophilic functions, the best recovery was obtained with SAX/PSA, with recovery ranging from 52.1% (3-hydroxycarbofuran) to 100.9% (3,4-dichloroaniline). Solid phase extraction was found to be more suitable than the liquid-liquid extraction for pesticides and their metabolites determination in terms of number of extracted compounds

  18. An artemisinin-derived dimer has highly potent anti-cytomegalovirus (CMV and anti-cancer activities.

    Directory of Open Access Journals (Sweden)

    Ran He

    Full Text Available We recently reported that two artemisinin-derived dimers (dimer primary alcohol 606 and dimer sulfone 4-carbamate 832-4 are significantly more potent in inhibiting human cytomegalovirus (CMV replication than artemisinin-derived monomers. In our continued evaluation of the activities of artemisinins in CMV inhibition, twelve artemisinin-derived dimers and five artemisinin-derived monomers were used. Dimers as a group were found to be potent inhibitors of CMV replication. Comparison of CMV inhibition and the slope parameter of dimers and monomers suggest that dimers are distinct in their anti-CMV activities. A deoxy dimer (574, lacking the endoperoxide bridge, did not have any effect on CMV replication, suggesting a role for the endoperoxide bridge in CMV inhibition. Differences in anti-CMV activity were observed among three structural analogs of dimer sulfone 4-carbamate 832-4 indicating that the exact placement and oxidation state of the sulfur atom may contribute to its anti-CMV activity. Of all tested dimers, artemisinin-derived diphenyl phosphate dimer 838 proved to be the most potent inhibitor of CMV replication, with a selectivity index of approximately 1500, compared to our previously reported dimer sulfone 4-carbamate 832-4 with a selectivity index of about 900. Diphenyl phosphate dimer 838 was highly active against a Ganciclovir-resistant CMV strain and was also the most active dimer in inhibition of cancer cell growth. Thus, diphenyl phosphate dimer 838 may represent a lead for development of a highly potent and safe anti-CMV compound.

  19. New organic nitrate-containing benzyloxy isonipecotanilide derivatives with vasodilatory and anti-platelet activity. (United States)

    de Candia, Modesto; Marini, Elisabetta; Zaetta, Giorgia; Cellamare, Saverio; Di Stilo, Antonella; Altomare, Cosimo D


    A number of new nitric oxide (NO)-precursors were synthesized by grafting nitrate-containing moieties on the structures of the benzyloxy isonipecotanilide derivatives 1 and 2 already reported as moderately potent antiplatelet agents. Various nitrooxy (ONO2)-alkyl side chains were covalently linked to the piperidine nitrogen of the parent compounds through carbamate and amide linkage, and the synthesis of a benzyl nitrate analog (15) of compound 1 was also achieved. The in vitro vasodilatory activities, as well as platelet anti-aggregatory effects, of the newly synthesized organic nitrates were assessed. The (ONO2)methyl carbamate-based derivative 5a and the benzyl nitrate analog 15, which on the other hand retain activity as inhibitors of ADP-induced platelet aggregation, exhibited strong NO-mediated vasodilatory effects on pre-contracted rat aorta strips, with EC50 values in the low nanomolar range (13 and 29 nM, respectively). Experiments carried out with the selectively inhibited soluble guanylate cyclase (sGC), which is the key enzyme of the NO-mediated pathway leading to vascular smooth muscle relaxation, confirmed the involvement of NO in the observed vasodilation. The nitrate derivatives proved to be stable in acidic aqueous solution and at pH 7.4. In human serum, unlike 5a, which showed not to undergo enzyme-catalyzed decomposition, the other tested (ONO2)-alkyl carbamate-based compounds (5b and 5e) and benzyl nitrate 15 underwent a faster degradation. However, their decomposition rates in serum were quite slow (t½>2.6 h), which suggests that nitrate moiety is poorly metabolized in blood plasma and that much of the in vitro anti-platelet activity has to be attributed to the intact (ONO2)-containing molecules.

  20. Submillisecond organic synthesis: Outpacing Fries rearrangement through microfluidic rapid mixing. (United States)

    Kim, Heejin; Min, Kyoung-Ik; Inoue, Keita; Im, Do Jin; Kim, Dong-Pyo; Yoshida, Jun-ichi


    In chemical synthesis, rapid intramolecular rearrangements often foil attempts at site-selective bimolecular functionalization. We developed a microfluidic technique that outpaces the very rapid anionic Fries rearrangement to chemoselectively functionalize iodophenyl carbamates at the ortho position. Central to the technique is a chip microreactor of our design, which can deliver a reaction time in the submillisecond range even at cryogenic temperatures. The microreactor was applied to the synthesis of afesal, a bioactive molecule exhibiting anthelmintic activity, to demonstrate its potential for practical synthesis and production.

  1. Insecticide resistance and activities of relative enzymes in different populations of the white backed planthopper

    Institute of Scientific and Technical Information of China (English)


    @@ White backed planthopper (WBPH), Sogatella furcifera (Horvath), is one of the most devastating insect pests on rice in Asia. Its control mainly depended on the chemical pesticides. Surveys of insecticide susceptibility revealed that organophosphorus and carbamate resistance has emerged since early 1980s in China and Japan. WBPH has the long distance migration property, and Heinrichs(1994) considered that the migration might influence the resistance level of planthoppers. So we conducted the comparative studies on insecticide susceptibility and activities of resistance relative enzymes in four WBPH populations collected from Zhejiang, Yunnan, and Hainan provinces of China in 1997.

  2. Production of N-13 labeled compounds with high specific activity

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Kazutoshi; Sasaki, Motoji; Yoshida, Yuichiro; Haradahira, Terushi; Inoue, Osamu [National Inst. of Radiological Sciences, Chiba (Japan)


    Nitrogen-13 was produced by irradiating ultra pure water saturated with a pure gas (N2, O2, He, H2) with 18 MeV protons. Ion species generated by irradiation were analyzed with radio ion chromatography systems. An automated equipment was developed to synthesize anhydrous (13N)NH3 as a synthetic precursor and (13N)p-nitrophenyl carbamate ((13N)NPC) as a model compound, using the (13N)NH3. The radiochemical yield and specific activity of (13N)NPC was high enough to carry out the receptor study with PET. (author)

  3. A model for estimating CO2 solubility in aqueous alkanolamines

    DEFF Research Database (Denmark)

    Gabrielsen, Jostein; Michelsen, Michael Locht; Stenby, Erling Halfdan


    Partial pressures of carbon dioxide (CO2) over aqueous solutions of monoethanolamine (MEA), diethanolamine (DEA), and N-methyldiethanolamine (MDEA) have been correlated using a simple approach where only one chemical equilibrium reaction is taken into account and assuming ideal gas and ideal liquid...... properties. The approach combines the Henry's law constant and the chemical reaction equilibrium constant for the formation of carbamate for primary and secondary alkanolamines (MEA, DEA) or bicarbonate for tertiary alkanolamines(MDEA), resulting in an explicit expression for calculating the partial pressure...

  4. Detection of Carbofuran with Immobilized Acetylcholinesterase Based on Carbon Nanotubes-Chitosan Modified Electrode

    Directory of Open Access Journals (Sweden)

    Shuping Zhang


    Full Text Available A sensitive and stable enzyme biosensor based on efficient immobilization of acetylcholinesterase (AChE to MWNTs-modified glassy carbon electrode (GCE with chitosan (CS by layer-by-layer (LBL technique for rapid determination of carbofuran has been devised. According to the inhibitory effect of carbamate pesticide on the enzymatic activity of AChE, we use carbofuran as a model pesticide. The inhibitory effect of carbofuran on the biosensor was proportional to concentration of carbofuran in the range from  g/L to  g/L with a detection limit of  g/L. This biosensor is a promising new method for pesticide analysis.

  5. Silver(I)-Catalyzed Synthesis of β-Oxopropylcarbamates from Propargylic Alcohols and CO2 Surrogate: A Gas-Free Process. (United States)

    Song, Qing-Wen; Zhou, Zhi-Hua; Yin, Hong; He, Liang-Nian


    The utilization of carbon dioxide poses major challenges owing to its high thermodynamic stability and kinetic inertness. To circumvent these problems, a simple reaction system is reported comprising ammonium carbamates as carbon dioxide surrogates, propargylic alcohols, and a silver(I) catalyst, for the effective conversion of a wide range of alcohols and secondary amines into the corresponding β-oxopropylcarbamates. A key feature of this strategy includes quantitative use of a carbon resource with high product yields under gas-free and mild reaction conditions. Notably, this catalytic protocol also works well for the carboxylative cyclization of propargylic amines and carbon dioxide surrogates to afford 2-oxazolidinones.

  6. Synthesis of Benzoxazolinone by Selenium-Catalyzed Carbonylation with Carbon Monoxide%硒催化羰基化合成苯并(哑/心)唑啉酮

    Institute of Scientific and Technical Information of China (English)

    凌冈; 陈金铸; 陆世维


    @@ Benzoxazolinones are a known class of commercially available compounds that are widely used in agriculture and industry. Traditionally, these compounds are made by the intramolecular cyclization of phenyl N-(2-hydroxyphenyl)carbamate which is produced by the reaction of o-aminophenol with phenyl chloroformate[1], this route needs a large number of steps from commercially available starting materials; another method is the reaction of o-aminophenol with much more urea, a lot of NH3 is released during the process[2,3]; the last method is from salicylic acid by treatment with hydroxylamine and commercial polyphosphoric acid, the yield of the reaction is 33%[4].

  7. Aqueous Titanium Trichloride Promoted Reductive Cyclization of o-Nitrostyrenes to Indoles: Development and Application to the Synthesis of Rizatriptan and Aspidospermidine. (United States)

    Tong, Shuo; Xu, Zhengren; Mamboury, Mathias; Wang, Qian; Zhu, Jieping


    Treatment of o-nitrostyrenes with aqueous TiCl3 solution at room temperature afforded indoles through a formal reductive C(sp(2) )-H amination process. A range of functions such as halides (Cl, Br), carbonyl (ester, carbamate), cyano, hydroxy, and amino groups were tolerated. From β,β-disubstituted o-nitrostyrenes, 2,3-disubstituted indoles were formed by a domino reduction/cyclization/migration process. Mild conditions, simple experimental procedure, ready accessibility of the starting materials and good to excellent yields characterize the present transformation. The methodology was used as a key step in a concise synthesis of rizatriptan and a formal total synthesis of aspidospermidine.

  8. Mechanistic studies of carbon monoxide reduction

    Energy Technology Data Exchange (ETDEWEB)

    Geoffroy, G.L.


    The progress made during the current grant period (1 January 1988--1 April 1990) in three different areas of research is summarized. The research areas are: (1) oxidatively-induced double carbonylation reactions to form {alpha}-ketoacyl complexes and studies of the reactivity of the resulting compounds, (2) mechanistic studies of the carbonylation of nitroaromatics to form isocyanates, carbamates, and ureas, and (3) studies of the formation and reactivity of unusual metallacycles and alkylidene ligands supported on binuclear iron carbonyl fragments. 18 refs., 5 figs., 1 tab.

  9. Synthesis and application of a new fluorous-tagged ammonia equivalent

    DEFF Research Database (Denmark)

    Nielsen, Simon Dalsgaard; Smith, Garrick; Begtrup, Mikael


    A novel fluorous-tagged ammonia equivalent has been developed. It is based on a nitrogen-oxygen bond, which can be cleaved in a traceless manner by a molybdenum complex or samarium diiodide. The application in the synthesis of ureas, amides, sulfonamides, and carbamates is described. The scope...... of the fluorous N--O linker is exemplified by the synthesis of itopride, a drug used for the treatment of functional dyspepsia. Itopride was synthesized with the aid of fluorous purification methods and the product was isolated in good overall yield, with high purity....

  10. Chemoenzymatic preparation of optically active trans-cyclohexane-1,2-diamine derivatives: an efficient synthesis of the analgesic U-(-)-50,488. (United States)

    González-Sabín, Javier; Gotor, Vicente; Rebolledo, Francisca


    Stereoespecific syntheses of (+/-)-trans-N,N-cyclohexane-1,2-diamines ((+/-)-4 a-g) were carried out from the corresponding (+/-)-trans-N,N-dialkylaminocyclohexanols by successive treatment with mesyl chloride and aqueous ammonia. The stereochemical outcome indicates the formation of a meso-aziridinium ion intermediate. Kinetic resolutions of diamines (+/-)-4 were efficiently accomplished in aminolysis reactions catalyzed by lipase B from Candida antarctica with ethyl acetate as the solvent and acyl donor. Acetamides and the remaining diamines, isolated as the benzyloxycarbonyl derivatives, were obtained with very high ee values (92-99%). One of the carbamates was used as a precursor of the analgesic U-(-)-50,488.

  11. Syntheses of aporphine and homoaporphine alkaloids by intramolecular ortho-arylation of phenols with aryl halides via SRN1 reactions in liquid ammonia. (United States)

    Barolo, Silvia M; Teng, Xin; Cuny, Gregory D; Rossi, Roberto A


    The photostimulated intramolecular ortho-arylation reactions of bromoarenes linked with pendant phenoxy containing N-substituted tetrahydroisoquinolines in liquid ammonia afforded aporphine (54-82% yield) alkaloid derivatives via SRN1 reactions. This strategy was extended for the first time to the synthesis of a homoaporphine derivative (40% yield). Tetrahydroisoquinoline precursors that contained electron-withdrawing groups on nitrogen (i.e., amides, sulfonamides, and carbamates) gave cyclized products, whereas precursors with basic nitrogens (i.e., NH or NMe) either failed to yield cyclized products or gave aporphines in only low yield.

  12. Protection against Acetylcholinesterase Inhibitor Toxicity by Alpha- Adrenergic Agonists (United States)


    in Rats 22 " fable 4 Prevalence of Soman-Evoked Behaviors at the Time of Maximal Expression 23 Table 5 Open-field Motor Activity 2 Days After Soman... Brecht , K.M. and Lenz, D.E. (1987). Effect of carboxylesterase inhibition on carbamate protection against soman toxicity. In: Proceedings of the 1987...Medical Defense Bioscience Review, Aberdeen Proving Ground. pp. 17-24. 33. Maxwell, D.M., Brecht . K.M. and O’neill, B.L1 (1987).The effect of

  13. The determination of aluminum, copper, iron, and lead in glycol formulations by atomic absorption spectroscopy (United States)


    Initial screening tests and the results obtained in developing procedures to determine Al, Cu, Fe, and Pb in glycol formulations are described. Atomic absorption completion was selected for Cu, Fe and Pb, and after comparison with emission spectroscopy, was selected for Al also. Before completion, carbon, iron, and lead are extracted with diethyl dithio carbamate (DDC) into methyl isobutyl ketone (MIBK). Aluminum was also extracted into MIBK using 8-hydroxyquinoline as a chelating agent. As little as 0.02 mg/l carbon and 0.06 mg/l lead or iron may be determined in glycol formulations. As little as 0.3 mg/l aluminum may be determined.

  14. Novel histamine H3-receptor antagonists and partial agonists with a non-aminergic structure


    Nickel, Tobias; Bauer, Ulrich; Schlicker, Eberhard; Kathmann, Markus; Göthert, Manfred; Sasse, Astrid; Stark, Holger; Schunack, Walter


    We determined the affinities of eight novel histamine H3-receptor ligands (ethers and carbamates) for H3-receptor binding sites and their agonistic/antagonistic effects in two functional H3-receptor models. The compounds differ from histamine in that the ethylamine chain is replaced by a propyloxy chain; in the three ethers mentioned below (FUB 335, 373 and 407), R is n-pentyl, 3-methylbutyl and 3,3-dimethylbutyl, respectively.The compounds monophasically inhibited [3H]-Nα-methylhistamine bin...

  15. End-labeled amino terminated monotelechelic glycopolymers generated by ROMP and Cu(I-catalyzed azide–alkyne cycloaddition

    Directory of Open Access Journals (Sweden)

    Ronald Okoth


    Full Text Available Functionalizable monotelechelic polymers are useful materials for chemical biology and materials science. We report here the synthesis of a capping agent that can be used to terminate polymers prepared by ring-opening metathesis polymerization of norbornenes bearing an activated ester. The terminating agent is a cis-butene derivative bearing a Teoc (2-trimethylsilylethyl carbamate protected primary amine. Post-polymerization modification of the polymer was accomplished by amidation with an azido-amine linker followed by Cu(I-catalyzed azide–alkyne cycloaddition with propargyl sugars. Subsequent Teoc deprotection and conjugation with pyrenyl isothiocyanates afforded well-defined end-labeled glycopolymers.

  16. Practical and Efficient Synthesis of α-Aminophosphonic Acids Containing 1,2,3,4-Tetrahydroquinoline or 1,2,3,4-Tetrahydroisoquinoline Heterocycles. (United States)

    Ordóñez, Mario; Arizpe, Alicia; Sayago, Fracisco J; Jiménez, Ana I; Cativiela, Carlos


    We report here a practical and efficient synthesis of α-aminophosphonic acid incorporated into 1,2,3,4-tetrahydroquinoline and 1,2,3,4-tetrahydroisoquinoline heterocycles, which could be considered to be conformationally constrained analogues of pipecolic acid. The principal contribution of this synthesis is the introduction of the phosphonate group in the N-acyliminium ion intermediates, obtained from activation of the quinoline and isoquinoline heterocycles or from the appropriate δ-lactam with benzyl chloroformate. Finally, the hydrolysis of phosphonate moiety with simultaneous cleavage of the carbamate afforded the target compounds.

  17. tert-Butyl N-(thiophen-2-ylcarbamate

    Directory of Open Access Journals (Sweden)

    Gene C. Hsu


    Full Text Available In the title compound, C9H13NO2S, the dihedral angle between the thiophene ring and the carbamate group is 15.79 (14°. In the crystal structure, intramolecular C—H...O interactions in tandem with the tert-butyl groups render the packing of adjacent molecules in the [001] direction nearly perpendicular [the angle between adjacent thiophene rings is 74.83 (7°]. An intermolecular N—H...O hydrogen bond gives rise to a chain extending along [001]. The crystal studied was found to be a racemic twin.

  18. Effect of solvents on the fumonisins analysis by high-performance liquid chromatography with AccQ.Fluor as the derivatizing reagent. (United States)

    Velázquez, C; Llovera, M; Plana, J; Canela, R


    The effect of several solvent systems on the chromatographic response of fumonisin B1 and B2 derived with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AccQ.Fluor) is described. Naturally contaminated corn samples were extracted and purified by a standard method. Then, samples were dissolved in different solvents, derived with AccQ.Fluor reagent and analysed using HPLC. Results were solvent dependent, methanol being the best one among all assayed solvents for both fumonisins studied and acetonitrile the poorest. o-Phthaldialdehyde (OPA) reagent was used as a reference method.

  19. Control of enzyme synthesis in the arginine deiminase pathway of Streptococcus faecalis.


    Simon, J.P.; Wargnies, B; Stalon, V


    The formation of the arginine deiminase pathway enzymes in Streptococcus faecalis ATCC 11700 was investigated. The addition of arginine to growing cells resulted in the coinduction of arginine diminase (EC, ornithine carbamoyltransferase (EC, and carbamate kinase (EC Growth on glucose-arginine or on glucose-fumarate-arginine produced a decrease in the specific activity of the arginine fermentation system. Aeration had a weak repressing effect on the arginine deimin...

  20. Effects of Three Drugs on Membrane Metabolism Against Cysticerci cellulosae in vitro

    Institute of Scientific and Technical Information of China (English)

    HAO Yanhong; LI Qingzhang; GAO Xuejun; LIU Yongjie; GAO Wenxue


    To investigate the effects and mechanisms of the benzimidazole carbamate and benmidine drugs on Cysticerci cellulosae and choose effective drugs on Cysticerci cellulosae, the membrane metabolism of Cysticerci cellulosae in vitro was tested after three kinds of drugs which were used respectively. The indexes included the contents of lipids, the contents of SA and the changes of the membrane fluidity. The results showed that oxfendazole could inhibit the membrane metabolism of immature and mature Cysticerci cellulosae in vitro, and albendazole only inhibited the mature one, while thibendimidine neither acted on the immature nor mature one.

  1. Time course of cholinesterase inhibition in adult rats treated acutely with carbaryl, carbofuran, formetanate, methomyl, methiocarb, oxamyl or propoxur. (United States)

    Padilla, S; Marshall, R S; Hunter, D L; Lowit, A


    To compare the toxicity of seven N-methyl carbamates, time course profiles for brain and red blood cell (RBC) cholinesterase (ChE) inhibition were established for each. Adult, male, Long Evans rats (n=4-5 dose group) were dosed orally with either carbaryl (30 mg/kg in corn oil); carbofuran (0.5 mg/kg in corn oil); formetanate HCl (10 mg/kg in water); methomyl (3 mg/kg in water); methiocarb (25 mg/kg in corn oil); oxamyl (1 mg/kg in water); or propoxur (20 mg/kg in corn oil). This level of dosing produced at least 40% brain ChE inhibition. Brain and blood were taken from 0.5 to 24 h after dosing for analysis of ChE activity using two different methods: (1) a radiometric method which limits the amount of reactivation of ChE activity, and (2) a spectrophotometric method (Ellman method using traditional, unmodified conditions) which may encourage reactivation. The time of peak ChE inhibition was similar for all seven N-methyl carbamate pesticides: 0.5-1.0 h after dosing. By 24 h, brain and RBC ChE activity in all animals returned to normal. The spectrophotometric method underestimated ChE inhibition. Moreover, there was a strong, direct correlation between brain and RBC ChE activity (radiometric assay) for all seven compounds combined (r(2)=0.73, slope 1.1), while the spectrophotometric analysis of the same samples showed a poor correlation (r(2)=0.09). For formetanate, propoxur, methomyl, and methiocarb, brain and RBC ChE inhibitions were not different over time, but for carbaryl, carbofuran and oxamyl, the RBC ChE was slightly more inhibited than brain ChE. These data indicate (1) the radiometric method is superior for analyses of ChE activity in tissues from carbamate-treated animals (2) that animals treated with these N-methyl carbamate pesticides are affected rapidly, and recover rapidly, and (3) generally, assessment of RBC ChE is an accurate predictor of brain ChE inhibition for these seven pesticides.

  2. Organo-mineral interactions mask the true sorption potential of biochars in soils. (United States)

    Singh, Neera; Kookana, Rai S


    The sorption of carbaryl (1-naphthyl methyl carbamate) and ethion [O,O,O',O'-tetraethyl S,S'-methylene bis(phosphorodithioate)] was studied in whole soils as well as after treatment of soil with 2% hydrofluoric acid (HF) to remove paramagnetic materials and to oxidize most forms of labile carbon by photo-oxidation with high energy (UV) on organo-mineral interactions of char in whole soils. This has implications for the modification of surfaces of the freshly applied biochars in soils due to organo-mineral interactions.

  3. Asymmetric Cooperative Catalysis in a Three-Component Reaction: Mechanism and Origin of Enantio- and Diastereoselectivities. (United States)

    Kisan, Hemanta K; Sunoj, Raghavan B


    Mechanistic insights gained through density functional theory (DFT M06 and B3LYP) computations on a three-component cooperative asymmetric catalytic reaction between a diazo ester, a carbamate, and an imine, catalyzed by dirhodium acetate and chiral phosphoric acid (Brønsted acid), are presented. The addition of the dirhodium-bound enol to the imine yielding an α,β-diamino ester is energetically more preferred over a potentially competitive protonation of the same enol leading to an α-amino ester.

  4. Mechanistic investigation of the NH-sulfoximination of sulfide. Evidence for λ(6)-sulfanenitrile intermediates. (United States)

    Lohier, Jean-François; Glachet, Thomas; Marzag, Hamid; Gaumont, Annie-Claude; Reboul, Vincent


    We report a new procedure for the preparation of NH-sulfoximines from sulfides using PIDA as an oxidant and ammonium carbamate as the ammonia source. Excellent yields were obtained with a wide range of sulfides. The formation of acetoxy- and methoxy-λ(6)-sulfanenitrile as intermediates was proposed, both of which were converted to the NH-sulfoximine by the action of the solvent. The structure of these intermediates was confirmed by (1)H, (13)C and (15)N NMR and HRMS analysis.

  5. Nematicides and nonconventional soil amendments in the management of root-knot nematode on cotton. (United States)

    Jorgenson, E C


    Granular and liquid commercial humates, with micronutrients, and a microbial fermentation product were compared in several combinations with nematicides for their effects on cotton lint yield and root-knot nematode suppression. Fumigant nematicides effectively reduced cotton root galling caused by root-knot nematodes, and cotton lint yields increased. Organophosphates and carbamates were not effective. Occasionally, cotton lint yields were increased or maintained with combination treatments o f humates, micronutrients, and a microbial fermentation product, but galling o f cotton roots by root-knot nematodes was usually not reduced by these treatments.

  6. Effects of several nematicides and benomyl on the incidence of weather fleck of tobacco

    Energy Technology Data Exchange (ETDEWEB)

    Miller, P.M.; Taylor, G.S.


    Four nematicides, including: 80% 1,3-dichloropropene and related chlorinated C/sub 3/ hydrocarbons + 20% methylisothiocyanate; 1,3-dichloropropene and related chlorinated C/sub 3/ hydrocarbons; ethyl-4-(methylthio)-m-tolyl isopropylphosphoramidate, and O,O-diethyl O-(p-(methylsulfinyl)phenyl) phosphorothioate gave good to excellent control of Pratylenchus penetrans. These nematicides also increase severity of weather fleck of tobacco. Methyl 1-(butylcarbamoyl)-2-benzimidazole-carbamate (benomyl) reduced P. penetrans populations over 50% and reduced the severity of fleck until late harvest. 5 references, 2 tables.

  7. The role of metal centres in reduction and carboxylation reactions utilizing carbon dioxide

    Energy Technology Data Exchange (ETDEWEB)

    Aresta, M.; Quaranta, E.; Tommasi, I. (Bari Univ. (Italy))


    The utilisation of carbon dioxide in synthesis of chemicals has been confined for a long time essentially to urea and salicylic acid synthesis. Quite recently, after the discovery of transition metal-carbon dioxide complexes, the direct carboxylation of organic substrates has been investigated, the reactions can be categorized as: functionalization of olefins, CO[sub 2] insertion into C-H bond via C-H activation, reaction with strained rings, reaction with amines to afford carbamates, synthesis or organic carbonates via reaction with oxetanes. (A.B.). 41 refs, 8 figs., 2 tabs.

  8. Zinc-promoted simple synthesis of oligomer-free N(alpha)-Fmoc-amino acids using Fmoc-Cl as an acylating agent under neutral conditions. (United States)

    Gopi, H N; Suresh Babu, V V


    A range of N(alpha)-Fmoc-protected amino acids, including those that contain t-butyl moiety, have been synthesized by employing Fmoc-Cl utilizing the activated, commercial zinc dust-promoted synthesis of carbamates under neutral conditions. A general procedure is described that circumvents the oligomerization side reaction normally noticed in Schotten-Baumann conditions. It is a simple, convenient and clean method. Thus, Fmoc-amino acids are obtained in high yield (85-92%) and purity as checked by thin-layer chromatography, high-performance liquid chromatography and other physical methods.

  9. Synthesis of some new Thieno[2,3-b]pyridines, Pyrimidino[4',5':4,5]thieno[2,3-b]pyridine and Pyridines Incorporating 5-Bromobenzofuran-2-yl Moiety. (United States)

    Abdelriheem, Nadia Abdelhamed; Ahmad, Sayed Abdel-Kader; Abdelhamid, Abdou Osman


    2-Sulfanyl-6-(2-thienyl)pyridine-3-carbonitrile, 1-Amino-6-(5-bromo-benzofuran-2-yl)-2-oxo-1,2-dihydro-pyridine-3-carbonitrile, thieno[2,3-b]pyridins, pyrimidino[4',5':4,5] thieno[2,3-b]pyridine, quinazoline and carbamate derivatives were synthesized from sodium 3-(5-bromobenzofuran-2-yl)-3-oxoprop-1-en-1-olate with. The newly synthesized compounds were elucidated by elemental analysis, spectral data, and alternative synthesis whenever possible and chemical transportation.

  10. PIXE analysis of heavy metals in water at sub-ppb levels (United States)

    Cecchi, R.; Ghermandi, G.; Calvelli, G.; Mittner, P.


    In order to determine the metal concentrations in natural water, we have used a preconcentration technique based on the extraction of the metals as carbamates and we have studied the treatment of large sample volumes (300-500 cm 3) for checking the capability of this method in low concentrations PIXE measurements. In analysis of solutions containing 1000, 500, 100, 50 and 10 {pg}/{cm 3} (ppt) of Fe, Co, Ni. Cu, Cd, Hg and Pb and Pd as internal standard, we have obtained a linear behaviour of the experimental results versus the nominal concentrations. The detection limits should permit PIXE application in measuring the amount of metal in sea water samples.

  11. 2-Phenyl-tetrahydropyrimidine-4(1H-ones – cyclic benzaldehyde aminals as precursors for functionalised β2-amino acids

    Directory of Open Access Journals (Sweden)

    Markus Nahrwold


    Full Text Available Novel procedures have been developed to condense benzaldehyde effectively with β-amino acid amides to cyclic benzyl aminals. Double carbamate protection of the heterocycle resulted in fully protected chiral β-alanine derivatives. These serve as universal precursors for the asymmetric synthesis of functionalised β2-amino acids containing acid-labile protected side chains. Diastereoselective alkylation of the tetrahydropyrimidinone is followed by a chemoselective two step degradation of the heterocycle to release the free β2-amino acid. In the course of this study, an L-asparagine derivative was condensed with benzaldehyde and subsequently converted to orthogonally protected (R-β2-homoaspartate.

  12. Proton Exchange in a Paramagnetic Chemical Exchange Saturation Transfer Agent from Experimental Studies and ab Initio Metadynamics Simulation. (United States)

    Pollet, Rodolphe; Bonnet, Célia S; Retailleau, Pascal; Durand, Philippe; Tóth, Éva


    The proton-exchange process between water and a carbamate has been studied experimentally and theoretically in a lanthanide-based paramagnetic chemical exchange saturation transfer agent endowed with potential multimodality detection capabilities (optical imaging, or T1 MRI for the Gd(III) analogue). In addition to an in-depth structural analysis by a combined approach (using X-ray crystallography, NMR, and molecular dynamics), our ab initio simulation in aqueous solution sheds light on the reaction mechanism for this proton exchange, which involves structural Grotthuss diffusion.

  13. Degradation of the pesticide carbofuran on clay and soil surfaces upon sunlight exposure. (United States)

    Mountacer, H; Atifi, A; Wong-Wah-Chung, P; Sarakha, M


    In the present study, the photolysis of carbofuran has been undertaken under sunlight conditions and at the surface of model supports such as clay films and different soils collected from two different sites in Morocco (Tirs and Dahs). In all conditions, an efficient degradation occurred owing to direct light absorption and also to photoinduced processes involving either clays or natural organic matter moities. On kaolin films, the photodegradation kinetics appears to follow a first-order process that clearly depends on the film thickness. The diffusion of carbofuran from the lower part to the illuminated surface was found to be negligible when compared to the photolysis process within the range of 20-70 μm. Thus, the photolysis rate constant at the surface of the solid support, k (0), was evaluated to be 7.0 × 10(-3) min(-1). Under these experimental conditions, the quantum yield was found equal to 2.1 × 10(-4). On soil surfaces, the disappearance rate constant was mainly attributed to photoinduced processes arising from natural organic matter. From the analytical point of view, the products were formed through (1) hydroxylation on the aromatic ring, (2) homolytic scission of the carbamate C-O bond leading to radical species formation, and (3) photohydrolysis of the carbamate C-O bond.


    Institute of Scientific and Technical Information of China (English)

    毛莹博; 方建军; 文娅; 赵文娟; 王珊; 魏志聪


    In this paper, through a series of experiment studies about the different ammonia-ammonium coupling of leaching system for the effect of copper oxide ore leaching, a significant influence sequence of the different ammonia-ammonium coupling of leaching system on the leaching rate of copper is determined as following : ammonia-ammonium carbamate > ammonia-ammonium carbonate > ammonia-ammonium chloride > ammonia-ammonium fluoride > ammonia-ammonium bicarbonate > ammonia-ammonium sulfate. The ammonia-ammonium carbamate leaching system is adopted as the experiment study of high calcium and magnesium, low grade and argillaceous copper oxide ore in Xinjiang Water, and the copper leaching rate is as high as 85. 25% .%通过不同氨-铵浸出体系对氧化铜矿浸出影响的试验研究,确定了不同氨-铵浸出体系对铜浸出率的显著性影响顺序是:氨-氨基甲酸铵>氨-碳酸铵>氨-氯化铵>氨-氟化铵>氨-碳酸氢铵>氨-硫酸铵.采用氨-氨基甲酸铵浸出体系对新疆滴水高钙镁低品位泥质氧化铜矿进行浸出试验,铜浸出率高达85.25%.

  15. Carcinogenic compounds in alcoholic beverages: an update. (United States)

    Pflaum, Tabea; Hausler, Thomas; Baumung, Claudia; Ackermann, Svenja; Kuballa, Thomas; Rehm, Jürgen; Lachenmeier, Dirk W


    The consumption of alcoholic beverages has been classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC) since 1988. More recently, in 2010, ethanol as the major constituent of alcoholic beverages and its metabolite acetaldehyde were also classified as carcinogenic to humans. Alcoholic beverages as multi-component mixtures may additionally contain further known or suspected human carcinogens as constituent or contaminant. This review will discuss the occurrence and toxicology of eighteen carcinogenic compounds (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, glyphosate, lead, 3-MCPD, 4-methylimidazole, N-nitrosodimethylamine, pulegone, ochratoxin A, safrole) occurring in alcoholic beverages as identified based on monograph reviews by the IARC. For most of the compounds of alcoholic beverages, quantitative risk assessment provided evidence for only a very low risk (such as margins of exposure above 10,000). The highest risk was found for ethanol, which may reach exposures in ranges known to increase the cancer risk even at moderate drinking (margin of exposure around 1). Other constituents that could pose a risk to the drinker were inorganic lead, arsenic, acetaldehyde, cadmium and ethyl carbamate, for most of which mitigation by good manufacturing practices is possible. Nevertheless, due to the major effect of ethanol, the cancer burden due to alcohol consumption can only be reduced by reducing alcohol consumption in general or by lowering the alcoholic strength of beverages.

  16. Mutagenic and cytotoxic activities of benfuracarb insecticide. (United States)

    Eren, Yasin; Erdoğmuş, Sevim Feyza; Akyıl, Dilek; Özkara, Arzu


    Benfuracarb is a carbamate insecticide used to control insect pests in vegetables and it has anti-acetylcholinesterase activity lower than other carbamates. Cytotoxic effects of benfuracarb were evaluated by using root growth inhibition (EC50), mitotic index (MI), and mitotic phase determinations on the root meristem cells of Allium cepa and mutagenic effects were determined in Salmonella typhymurium Ames test by TA98 and TA100 strains with and without metabolic activation. In Allium test, 1 % DMSO was used as negative control group and 10 ppm MMS was used as positive control group. 75 ppm concentration of benfuracarb was found as EC50. In MI and mitotic phases determination study, 37.5, 75 and 150 ppm doses of benfuracarb were used. Dose-dependent cytotoxic activity was found by root growth inhibition and MI studies. It was identified that mitotic inhibition activity of benfuracarb was higher than 10 ppm MMS. In Ames test, mutagenic activity was not observed and over 200 µg/plate of benfuracarb was determined as cytotoxic to S. typhymurium strains. Benfuracarb can be called as "mitotic inhibitor" but not called as mutagen.

  17. Carboxylesterase-2 is a highly sensitive target of the antiobesity agent orlistat with profound implications in the activation of anticancer prodrugs. (United States)

    Xiao, Da; Shi, Deshi; Yang, Dongfang; Barthel, Benjamin; Koch, Tad H; Yan, Bingfang


    Orlistat has been the most used anti-obesity drug and the mechanism of its action is to reduce lipid absorption by inhibiting gastrointestinal lipases. These enzymes, like carboxylesterases (CESs), structurally belong to the α/β hydrolase fold superfamily. Lipases and CESs are functionally related as well. Some CESs (e.g., human CES1) have been shown to hydrolyze lipids. This study was designed to test the hypothesis that orlistat inhibits CESs with higher potency toward CES1 than CES2, a carboxylesterase with little lipase activity. Liver microsomes and recombinant CESs were tested for the inhibition of the hydrolysis of standard substrates and the anticancer prodrugs pentyl carbamate of p-aminobenzyl carbamate of doxazolidine (PPD) and irinotecan. Contrary to the hypothesis, orlistat at 1 nM inhibited CES2 activity by 75% but no inhibition on CES1, placing CES2 one of the most sensitive targets of orlistat. The inhibition varied among some CES2 polymorphic variants. Pretreatment with orlistat reduced the cell killing activity of PPD. Certain mouse but not rat CESs were also highly sensitive. CES2 is responsible for the hydrolysis of many common drugs and abundantly expressed in the gastrointestinal track and liver. Inhibition of this carboxylesterase probably presents a major source for altered therapeutic activity of these medicines if co-administered with orlistat. In addition, orlistat has been linked to various types of organ toxicities, and this study provides an alternative target potentially involved in these toxicological responses.

  18. Insecticide resistance in bedbugs in Thailand and laboratory evaluation of insecticides for the control of Cimex hemipterus and Cimex lectularius (Hemiptera: Cimicidae). (United States)

    Tawatsin, Apiwat; Thavara, Usavadee; Chompoosri, Jakkrawarn; Phusup, Yutthana; Jonjang, Nisarat; Khumsawads, Chayada; Bhakdeenuan, Payu; Sawanpanyalert, Pathom; Asavadachanukorn, Preecha; Mulla, Mir S; Siriyasatien, Padet; Debboun, Mustapha


    Bedbugs are found in many countries around the world, and in some regions they are resistant to numerous insecticides. This study surveyed bedbugs in Thailand and determined their resistance to insecticides. The surveys were carried out in six provinces that attract large numbers of foreign tourists: Bangkok, Chonburi, Chiang Mai, Ubon Ratchathani, Phuket, and Krabi. Bedbugs were collected from hotels and colonized in the laboratory to evaluate their resistance to insecticides. Cimex hemipterus (F.) was found in some hotels in Bangkok, Chonburi, Phuket, and Krabi, whereas Cimex lectularius L. was found only in hotels in Chiang Mai. No bedbugs were found in Ubon Ratchathani. The colonized bedbugs showed resistance to groups of insecticides, including organochlorines (dichlorodiphenyl trichloroethane, dieldrin), carbamates (bendiocarb, propoxur), organophosphates (malathion, fenitrothion), and pyrethroids (cyfluthrin, deltamethrin, permethrin, lambda-cyhalothrin, etofenprox) in tests using World Health Organization insecticide-impregnated papers. The new insecticides imidacloprid (neonicotinoid group), chlorfenapyr (pyrrole group), and fipronil (phenylpyrazole group) were effective against the bedbugs; however, organophosphate (diazinon), carbamates (fenobucarb, propoxur), and pyrethroids (bifenthrin, cypermethrin, esfenvalerate, etofenprox) were ineffective. Aerosols containing various pyrethroid insecticides with two to four different active ingredients were effective against the bedbugs. The results obtained from this study suggested that both species of bedbugs in Thailand have developed marked resistance to various groups of insecticides, especially those in the pyrethroid group, which are the most common insecticides used for pest control. Therefore, an integrated pest management should be implemented for managing bedbugs in Thailand.

  19. Hydrogen Bonds between Acidic Protons from Alkynes (C–H···O and Amides (N–H···O and Carbonyl Oxygen Atoms as Acceptor Partners

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    Pierre Baillargeon


    Full Text Available Crystals of tert-butyl (2S-2-(prop-2-yn-1-ylcarbamoylpyrrolidine-1-carboxylate (Boc-L-Pro-NHCH2CCH have been obtained. The title compound crystallizes easily as sharp needles in orthorhombic system, space group P 21 21 21 with a = 9.2890(2, b = 9.7292(2, c = 15.7918(4 Å, V = 1427.18(6 Å3, and Z = 4. The main feature of the structure is the orientation of the carbamate and amide. Their dipoles add up and the molecule displays an electric dipole moment of 5.61 D from B3LYP/6-31G(d calculations. The antiparallel H bonding of amides and the alignment of dipoles induce columnar stacking (the dipole moment along the columnar a axis is 4.46 D for each molecule. The other components across the other axes are, therefore weaker, (3.17 D and 1.23 D along the b and c axes, resp.. The resulting anisotropic columns pack side by side, in an antiparallel fashion mostly by (alkyne CH···O=C (carbamate interactions.

  20. Current Perspectives on Plague Vector Control in Madagascar: Susceptibility Status of Xenopsylla cheopis to 12 Insecticides. (United States)

    Miarinjara, Adélaïde; Boyer, Sébastien


    Plague is a rodent disease transmissible to humans by infected flea bites, and Madagascar is one of the countries with the highest plague incidence in the world. This study reports the susceptibility of the main plague vector Xenopsylla cheopis to 12 different insecticides belonging to 4 insecticide families (carbamates, organophosphates, pyrethroids and organochlorines). Eight populations from different geographical regions of Madagascar previously resistant to deltamethrin were tested with a World Health Organization standard bioassay. Insecticide susceptibility varied amongst populations, but all of them were resistant to six insecticides belonging to pyrethroid and carbamate insecticides (alphacypermethrin, lambdacyhalothrin, etofenprox, deltamethrin, bendiocarb and propoxur). Only one insecticide (dieldrin) was an efficient pulicide for all flea populations. Cross resistances were suspected. This study proposes at least three alternative insecticides (malathion, fenitrothion and cyfluthrin) to replace deltamethrin during plague epidemic responses, but the most efficient insecticide may be different for each population studied. We highlight the importance of continuous insecticide susceptibility surveillance in the areas of high plague risk in Madagascar.

  1. Widespread pyrethroid and DDT resistance in the major malaria vector Anopheles funestus in East Africa is driven by metabolic resistance mechanisms.

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    Charles Mulamba

    Full Text Available BACKGROUND: Establishing the extent, geographical distribution and mechanisms of insecticide resistance in malaria vectors is a prerequisite for resistance management. Here, we report a widespread distribution of insecticide resistance in the major malaria vector An. funestus across Uganda and western Kenya under the control of metabolic resistance mechanisms. METHODOLOGY/PRINCIPAL FINDINGS: Female An. funestus collected throughout Uganda and western Kenya exhibited a Plasmodium infection rate between 4.2 to 10.4%. Widespread resistance against both type I (permethrin and II (deltamethrin pyrethroids and DDT was observed across Uganda and western Kenya. All populations remain highly susceptible to carbamate, organophosphate and dieldrin insecticides. Knockdown resistance plays no role in the pyrethroid and DDT resistance as no kdr mutation associated with resistance was detected despite the presence of a F1021C replacement. Additionally, no signature of selection was observed on the sodium channel gene. Synergist assays and qRT-PCR indicated that metabolic resistance plays a major role notably through elevated expression of cytochrome P450s. DDT resistance mechanisms differ from West Africa as the L119F-GSTe2 mutation only explains a small proportion of the genetic variance to DDT resistance. CONCLUSION: The extensive distribution of pyrethroid and DDT resistance in East African An. funestus populations represents a challenge to the control of this vector. However, the observed carbamate and organophosphate susceptibility offers alternative solutions for resistance management.

  2. β-d-Glucosidase as "key enzyme" for sorghum cyanogenic glucoside (dhurrin) removal and beer bioflavouring. (United States)

    Tokpohozin, Sedjro Emile; Fischer, Susann; Sacher, Bertram; Becker, Thomas


    Sorghum malt used during African beer processing contains a high level of cyanogenic glucoside (dhurrin), up to 1375 ppm. In traditional sorghum malting and mashing, dhurrin is not sufficiently hydrolyzed due to uncontrolled germination and a high gelatinization temperature. The cyanide content of traditional African beers (11 ppm) is higher than the minimum dose (1 ppm) required to form carcinogenic ethyl carbamate during alcoholic fermentation. In the detoxification process, aryl-β-d-glucosidase (dhurrinase) is the "key component". For significant dhurrin hydrolysis during mashing, optimizing dhurrinase synthesis during malting is a good solution to reduce dhurrin completely to below the harmful dose in the sorghum wort. Lactic acid bacteria which exhibit aryl-β-d-glucosidase prior to alcoholic fermentation may help to reduce ethyl carbamate content in alcoholic beverages. Moreover, some specific β-d-glucosidases have a dual property, being able to cleave and synthesize glucosides bonds and thereby generating good precursors for beer bioflavouring.

  3. Purification and properties of the inducible enzyme cyanase. (United States)

    Anderson, P M


    Cyanase (cyanate hydrolase EC has been purified 270-fold to a high state of purity from Escherichia coli B. The native enzyme has a molecular weight of approximately 150 000 as estimated by sucrose density gradient centrifugation and gel-filtration chromatography on Bio-Gel P-300. The enzyme is an oligomer composed of apparently identical subunits which have a molecular weight of approximately 15 000 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Amino acid analyses showed that the enzyme contains no tryptophan and a single histidine residue, based on a subunit molecular weight of 14 661. Catalytic hydrolysis of cyanate was found to be dependent on the patience of bicarbonate and to be affected by ionic strength. The concentration of bicarbonate required to give half-maximal activity in the presence of 2 mM potassium cyanate was 0.1 mM. The apparent Km for cyanate in the presence of 3 mM bicarbonate is 0.6 mM. The initial product of the reaction is carbamate (or a related, unstable compound and/or carbamate precursor) which subsequently decomposes to ammonia and bicarbonate.


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    Full Text Available Teak wood (Tectona grandis Lf. in the form of sawdust a byproduct/waste from the furniture industry has a considerable amount and has not been utilized optimally. This study aims to determine the content of extractive teak wood (Tectona grandis Lf.. The method used is the hot water solubility. Muna's teak wood powder weighing 4,076 g soaked in distilled water as much as 100 ml glass flask, then heated in a water bath at a temperature of 100 oC for 3 hours. The content of extractive dissolved in a liquid further characterized using Py-GCMS. Results of the analysis of Py-GCMS to extract teak wood showed concentrations of some substances, such as Carbamic acid (70,70%, mono ammonium salt (CAS Ammonium carbamate (70,70%, Acetic acid (CAS Ethylic acid (10,52%, Acetic acid (CAS Ethylic acid (2,35%, Acetic acid (CAS Ethylic acid (3,26%, and Phenol (CAS Izal (13,17%

  5. Pesticides residues in the Prochilodus costatus (Valenciennes, 1850) fish caught in the São Francisco River, Brazil. (United States)

    Oliveira, Fabiano A; Reis, Lilian P G; Soto-Blanco, Benito; Melo, Marília M


    The objective of this study was to determine the levels of pesticides in the fish Prochilodus costatus caught in São Francisco River, one of most important rivers in Brazil. Thirty-six fish were captured in three different areas, and samples of the dorsal muscle and pooled viscera were collected for toxicological analysis. We evaluated the presence of 150 different classes of insecticides, fungicides, herbicides and acaricides by multiresidue analysis technique using liquid chromatography-tandem mass spectrometry (LC-MS/MS), with the limit of detection of 5 ppb. In this study, organophosphorus and carbamate pesticides were detected at the highest levels in the caught fish. Among the 41 organophosphorus pesticides surveyed, nine types were detected (chlorpyrifos, diazinon, dichlorvos, disulfoton, ethion, etrimfos, phosalone, phosmet and pyrazophos) in the muscle, viscera pool, or both in 22 (61.1%) fish. Sampled tissues of 20 (55.6%) fish exhibited at least one of the eight evaluated carbamate pesticides and their metabolites: aldicarb, aldicarb sulfoxide, carbaryl, carbofuran, carbosulfan, furathiocarb, methomyl and propoxur. Fungicides (carbendazim, benalaxyl, kresoxim-methyl, trifloxystrobin, pyraclostrobin and its metabolite BF 500 pyraclostrobin), herbicides (pyridate and fluasifop p-butyl), acaricide (propargite) and pyrethroid (flumethrin) were also detected. In conclusion, P. costatus fish caught in the São Francisco River contained residues of 17 different pesticides, in both muscles and the viscera pool, indicating heavy environmental contamination by pesticides in the study area.

  6. Pesticides in the propolis at São Saulo State, Brazil - doi: 10.4025/actascianimsci.v34i4.15859 Pesticides in the propolis at São Saulo State, Brazil - doi: 10.4025/actascianimsci.v34i4.15859

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    Samir Moura Kadri


    Full Text Available The increasing demand for propolis has caused a raise in its production. However, an increasingly pesticide-dependent agriculture is a great concern with regard to bees, their produce and environmental contamination. Current analysis evaluates the presence of pesticides (organochlorines, organophosphates, pyrethroids, carbamates, herbicides, fungicides and acaricides in samples of propolis from the state of São Paulo, Brazil. Beekeepers from several localities in the state provided samples of propolis (50, which were collected, stored in non-toxic plastic bags and maintained in a freezer for analyses. Possible pesticide residues were examined by gas chromatography method but no pesticide residues were detected in the examined propolis samples. Propolis analyzed in the state of São Paulo did not show any pesticide contamination. The increasing demand for propolis has caused a raise in its production. However, an increasingly pesticide-dependent agriculture is a great concern with regard to bees, their produce and environmental contamination. Current analysis evaluates the presence of pesticides (organochlorines, organophosphates, pyrethroids, carbamates, herbicides, fungicides and acaricides in samples of propolis from the state of São Paulo, Brazil. Beekeepers from several localities in the state provided samples of propolis (50, which were collected, stored in non-toxic plastic bags and maintained in a freezer for analyses. Possible pesticide residues were examined by gas chromatography method but no pesticide residues were detected in the examined propolis samples. Propolis analyzed in the state of São Paulo did not show any pesticide contamination.

  7. Utilization of an intramolecular hydrogen bond to increase the CNS penetration of an NK(1) receptor antagonist. (United States)

    Ashwood, V A; Field, M J; Horwell, D C; Julien-Larose, C; Lewthwaite, R A; McCleary, S; Pritchard, M C; Raphy, J; Singh, L


    This paper describes the synthesis and physical and biological effects of introducing different substituents at the alpha-position of the tryptophan containing neurokinin-1 receptor antagonist [(R)-2-(1H-indol-3-yl)-1-methyl-1-((S)-1-phenyl-ethylcarbamoyl)-ethyl]-carbamic acid benzofuran-2-ylmethyl ester (CI 1021). The described compounds all exhibit less than 5 nM binding affinities for the human neurokinin-1 receptor and selectivity over the tachykinin NK(2) and NK(3) receptor subtypes. Application of variable temperature nuclear magnetic resonance spectroscopy studies of the amide and urethane protons was utilized to determine the existence of an intramolecular hydrogen bond. This intramolecular hydrogen bond increases the apparent lipophilicity to allow increased central nervous system penetration and pharmacological activity (gerbil foot tap test) in the case of the highest affinity compound [(S)-1-dimethylaminomethyl-2-(1H-indol-3-yl)-1-((S)-1-phenyl-ethylcarbamoyl)-ethyl]-carbamic acid benzofuran-2-ylmethyl ester (PD 174424) over those analogues that could not form an intramolecular hydrogen bond.

  8. Coextracted dissolved organic carbon has a suppressive effect on the acetylcholinesterase inhibition assay. (United States)

    Neale, Peta A; Escher, Beate I


    The acetylcholinesterase (AChE) inhibition assay is frequently applied to detect organophosphates and carbamate pesticides in different water types, including dissolved organic carbon (DOC)-rich wastewater and surface water. The aim of the present study was to quantify the effect of coextracted DOC from different water samples on the commonly used enzyme-based AChE inhibition assay. Approximately 40% to 70% of DOC is typically recovered by solid-phase extraction, and this comprises not only organic micropollutants but also natural organic matter. The inhibition of the water extracts in the assay differed greatly from the expected mixture effects based on chemical analysis of organophosphates and carbamates. Binary mixture experiments with the known AChE inhibitor parathion and the water extracts showed reduced toxicity in comparison with predictions using the mixture models of concentration addition and independent action. In addition, the extracts and reference organic matter had a suppressive effect on a constant concentration of parathion. The present study thus indicated that concentrations of DOC as low as 2 mg carbon/L can impair the AChE inhibition assay and, consequently, that only samples with a final DOC concentration of less than 2 mgC /L are suitable for this assay. To check for potential suppression in environmental samples, standard addition experiments using an AChE-inhibiting reference compound are recommended.

  9. A new class of single-component absorbents for reversible carbon dioxide capture under mild conditions. (United States)

    Barzagli, Francesco; Lai, Sarah; Mani, Fabrizio


    Some inexpensive and commercially available secondary amines reversibly react with CO2 at room temperature and ambient pressure to yield carbonated species in the liquid phase in the absence of any additional solvent. These solvent-free absorbents have a high CO2 capture capacity (0.63-0.65 mol CO2 /mol amine) at 1.0 bar (=100 kPa), combined with low-temperature reversibility at ambient pressure. (13) C NMR spectroscopy analysis identified the carbonated species as the carbamate salts and unexpected carbamic acids. These absorbents were used for CO2 (15 and 40 % in air) capture in continuous cycles of absorption-desorption carried out in packed columns, yielding an absorption efficiency of up to 98.5 % at absorption temperatures of 40-45 °C and desorption temperatures of 70-85 °C at ambient pressure. The absence of any parasitic solvent that requires to be heated and stability towards moisture and heating could result in some of these solvent-free absorbents being a viable alternative to aqueous amines for CO2 chemical capture.

  10. Reconstitution of an active arginine deiminase pathway in Mycoplasma pneumoniae M129. (United States)

    Rechnitzer, Hagai; Rottem, Shlomo; Herrmann, Richard


    Some species of the genus Mycoplasma code for the arginine deiminase pathway (ADI), which enables these bacteria to produce ATP from arginine by the successive reaction of three enzymes: arginine deiminase (ArcA), ornithine carbamoyltransferase (ArcB), and carbamate kinase (ArcC). It so far appears that independently isolated strains of Mycoplasma pneumoniae encode an almost identical truncated version of the ADI pathway in which the proteins ArcA and ArcB have lost their original enzymatic activities due to the deletion of significant regions of these proteins. To study the consequences of a functional ADI pathway, M. pneumoniae M129 was successfully transformed with the cloned functional arcA, arcB, and arcC genes from Mycoplasma fermentans. Enzymatic tests showed that while the M. pneumoniae ArcAB and ArcABC transformants possess functional arginine deiminase, ornithine carbamoyltransferase, and carbamate kinase, they were unable to grow on arginine as the sole energy source. Nevertheless, infection of a lung epithelial cell line, A549, with the M. pneumoniae transformants showed that almost 100% of the infected host cells were nonviable, while most of the lung cells infected with nontransformed M. pneumoniae were viable under the same experimental conditions.

  11. Alkyl amine and vegetable oil mixture-a viable candidate for CO2 capture and utilization. (United States)

    Uma Maheswari, A; Palanivelu, K


    In this present work, the absorption of CO2 in alkyl amines and vegetable oil mixture has been evaluated. The results showed that the absorption is higher in alkyl amines and vegetable oil mixture compared with the aqueous alkyl amines. In addition to that, by employing the greener and non-toxic vegetable oil media, the CO2 gas has been captured as well as converted into value-added products, such as carbamates of ethylenediamine, diethylenetriamine, and triethylenetetramine. The carbamates have been isolated and characterized by Fourier transform infrared and (1)H and (13)C nuclear magnetic resonance spectroscopic techniques. The formation of these products in precipitate form has not been observed in the case of aqueous medium. Among the various alkyl amine and vegetable oil combinations, triethylenetetramine in coconut oil medium showed the maximum CO2 capture capacity of 72%. The coconut oil used for the process has been recovered, recycled, and reused for 3 cycles. Thus, this novel scheme seems to be a better alternative to conquer the drawback of aqueous amine-based CO2 capture as well as for the capture and utilization of the CO2 gas to gain the value-added products.

  12. Mechanisms of low temperature capture and regeneration of CO2 using diamino protic ionic liquids. (United States)

    Simons, Tristan J; Verheyen, Thomas; Izgorodina, Ekaterina I; Vijayaraghavan, R; Young, Scott; Pearson, Andrew K; Pas, Steven J; MacFarlane, Douglas R


    Carbon dioxide (CO2) chemical absorption and regeneration was investigated in two diamino carboxylate protic ionic liquids (PILs), dimethylethylenediamine formate (DMEDAH formate) and dimethylpropylenediamine acetate (DMPDAH acetate), using novel calorimetric techniques. The PILs under study have previously been shown to possess a CO2 absorption capacity similar to the industrial standard, 30% aqueous MEA, while requiring much lower temperatures to release the captured CO2. We show that this is in part due to the fact that the PILs exhibit enthalpies of CO2 desorption as low as 40 kJ mol(-1), significantly lower than the 85 kJ mol(-1) required for 30% aqueous MEA. Computational and spectroscopic analyses were used to probe the mechanism of CO2 capture, which was found to proceed via the formation of carbamate moieties on the primary amine of both DMEDAH and DMPDAH. Evidence was also found that weakly acidic counter-ions such as formate and acetate provide, unexpectedly, an additional proton acceptor site in the traditional carbamate mechanism, revealing opportunities to increase CO2 uptake capacity in the future through careful design of the anion and cation used in the PIL capture agent.

  13. Nitrosamine formation in amine scrubbing at desorber temperatures. (United States)

    Fine, Nathan A; Goldman, Mark J; Rochelle, Gary T


    Amine scrubbing is a thermodynamically efficient and industrially proven method for carbon capture, but amine solvents can nitrosate in the desorber, forming potentially carcinogenic nitrosamines. The kinetics of reactions involving nitrite and monoethanolamine (MEA), diethanolamine (DEA), methylethanolamine (MMEA), and methyldiethanolamine (MDEA) were determined under desorber conditions. The nitrosations of MEA, DEA, and MMEA are first order in nitrite, carbamate species, and hydronium ion. Nitrosation of MDEA, a tertiary amine, is not catalyzed by the addition of CO2 since it cannot form a stable carbamate. Concentrated and CO2 loaded MEA was blended with low concentrations of N-(2-hydroxyethyl) glycine (HeGly), hydroxyethyl-ethylenediamine (HEEDA), and DEA, secondary amines common in MEA degradation. Nitrosamine yield was proportional to the concentration of secondary amine and was a function of CO2 loading and temperature. Blends of tertiary amines with piperazine (PZ) showed n-nitrosopiperazine (MNPZ) yields close to unity, validating the slow nitrosation rates hypothesized for tertiary amines. These results provide a useful tool for estimating nitrosamine accumulation over a range of amine solvents.

  14. Herbicide and pesticide occurrence in the soils of children's playgrounds in Sarajevo, Bosnia and Herzegovina. (United States)

    Sapcanin, Aida; Cakal, Mirsada; Imamovic, Belma; Salihovic, Mirsada; Pehlic, Ekrem; Jacimovic, Zeljko; Jancan, Gordan


    Pesticide pollution in Sarajevo public playgrounds is an important health and environmental issue, and the lack of information about it is causing concerns amongst the general population as well as researchers. Since children are in direct contact with surface soils on children's playgrounds, such soils should be much more carefully examined. Furthermore, herbicides and pesticides get transmitted from soil surfaces brought from outside the urban areas, or they get dispersed following their direct applications in urban areas. Infants' and children's health can be directly affected by polluted soils because of the inherent toxicity and widespread use of the different pesticides in urban environments such as playgrounds. In addition to that, the presence of chromated copper arsenate (CCA) wood preservative pesticide found as soil pollutant in playing equipment was also documented. Soil samples from playgrounds were collected and analyzed for triazines, carbamates, dithiocarbamates, phenolic herbicides and organochlorine pesticides. Samples for the determination of heavy metals Cu, Cr and As were prepared by microwave-assisted acid digestion, and the findings were determined by using an inductively coupled plasma optical emission spectrometer. Triazines, carbamates, dithiocarbamates, chlorphenoxy compounds, phenolic herbicides, organochlorine pesticides and organotin compounds were detected in playground soils and their determined concentrations (mg/kg) were respectively found as follows: playground soils.

  15. Acetylcholinesterase as a Biomarker in Environmental and Occupational Medicine: New Insights and Future Perspectives

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    Maria Giulia Lionetto


    Full Text Available Acetylcholinesterase (AChE is a key enzyme in the nervous system. It terminates nerve impulses by catalysing the hydrolysis of neurotransmitter acetylcholine. As a specific molecular target of organophosphate and carbamate pesticides, acetylcholinesterase activity and its inhibition has been early recognized to be a human biological marker of pesticide poisoning. Measurement of AChE inhibition has been increasingly used in the last two decades as a biomarker of effect on nervous system following exposure to organophosphate and carbamate pesticides in occupational and environmental medicine. The success of this biomarker arises from the fact that it meets a number of characteristics necessary for the successful application of a biological response as biomarker in human biomonitoring: the response is easy to measure, it shows a dose-dependent behavior to pollutant exposure, it is sensitive, and it exhibits a link to health adverse effects. The aim of this work is to review and discuss the recent findings about acetylcholinesterase, including its sensitivity to other pollutants and the expression of different splice variants. These insights open new perspective for the future use of this biomarker in environmental and occupational human health monitoring.

  16. Current Perspectives on Plague Vector Control in Madagascar: Susceptibility Status of Xenopsylla cheopis to 12 Insecticides.

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    Adélaïde Miarinjara


    Full Text Available Plague is a rodent disease transmissible to humans by infected flea bites, and Madagascar is one of the countries with the highest plague incidence in the world. This study reports the susceptibility of the main plague vector Xenopsylla cheopis to 12 different insecticides belonging to 4 insecticide families (carbamates, organophosphates, pyrethroids and organochlorines. Eight populations from different geographical regions of Madagascar previously resistant to deltamethrin were tested with a World Health Organization standard bioassay. Insecticide susceptibility varied amongst populations, but all of them were resistant to six insecticides belonging to pyrethroid and carbamate insecticides (alphacypermethrin, lambdacyhalothrin, etofenprox, deltamethrin, bendiocarb and propoxur. Only one insecticide (dieldrin was an efficient pulicide for all flea populations. Cross resistances were suspected. This study proposes at least three alternative insecticides (malathion, fenitrothion and cyfluthrin to replace deltamethrin during plague epidemic responses, but the most efficient insecticide may be different for each population studied. We highlight the importance of continuous insecticide susceptibility surveillance in the areas of high plague risk in Madagascar.

  17. Multi-function oxidases are responsible for the synergistic interactions occurring between repellents and insecticides in mosquitoes

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    Duchon Stéphane


    Full Text Available Abstract Background With the spread of pyrethroid resistance in mosquitoes, the combination of an insecticide (carbamate or organophosphate with a repellent (DEET is considered as a promising alternative strategy for the treatment of mosquito nets and other relevant materials. The efficacy of these mixtures comes from the fact that they reproduce pyrethroid features and that positive interactions occur between insecticides and repellent. To better understand the mechanisms involved and assess the impact of detoxifying enzymes (oxidases and esterases in these interactions, bioassays were carried out in the laboratory against the main dengue vector Aedes aegypti. Methods Topical applications of DEET and propoxur (carbamate, used alone or as a mixture, were carried out on female mosquitoes, using inhibitors of the two main detoxification pathways in the insect. PBO, an inhibitor of multi-function oxidases, and DEF, an inhibitor of esterases, were applied one hour prior to the main treatment. Results Results showed that synergism between DEET and propoxur disappeared in the presence of PBO but not with DEF. This suggests that oxidases, contrary to esterases, play a key role in the interactions occurring between DEET and cholinesterase inhibitors in mosquitoes. Conclusion These findings are of great interest for the implementation of "combination nets" in the field. They support the need to combine insecticide with repellent to overcome insecticide resistance in mosquitoes of public health importance.

  18. Current Perspectives on Plague Vector Control in Madagascar: Susceptibility Status of Xenopsylla cheopis to 12 Insecticides (United States)

    Miarinjara, Adélaïde; Boyer, Sébastien


    Plague is a rodent disease transmissible to humans by infected flea bites, and Madagascar is one of the countries with the highest plague incidence in the world. This study reports the susceptibility of the main plague vector Xenopsylla cheopis to 12 different insecticides belonging to 4 insecticide families (carbamates, organophosphates, pyrethroids and organochlorines). Eight populations from different geographical regions of Madagascar previously resistant to deltamethrin were tested with a World Health Organization standard bioassay. Insecticide susceptibility varied amongst populations, but all of them were resistant to six insecticides belonging to pyrethroid and carbamate insecticides (alphacypermethrin, lambdacyhalothrin, etofenprox, deltamethrin, bendiocarb and propoxur). Only one insecticide (dieldrin) was an efficient pulicide for all flea populations. Cross resistances were suspected. This study proposes at least three alternative insecticides (malathion, fenitrothion and cyfluthrin) to replace deltamethrin during plague epidemic responses, but the most efficient insecticide may be different for each population studied. We highlight the importance of continuous insecticide susceptibility surveillance in the areas of high plague risk in Madagascar. PMID:26844772

  19. Insecticide susceptibility of Anopheles coluzzii and Anopheles gambiae mosquitoes in Ibadan, Southwest Nigeria. (United States)

    Okorie, P N; Ademowo, O G; Irving, H; Kelly-Hope, L A; Wondji, C S


    The emergence of insecticide resistance in Anopheles (Diptera: Culicidae) mosquitoes has great implications for malaria control in Nigeria. This study aimed to determine the dynamics of insecticide susceptibility levels and the frequency of knock-down resistance (kdr) mutations (L1014F) in wild Anopheles coluzzii Coetzee & Wilkerson sp. n. and Anopheles gambiae Giles from the Ojoo and Bodija areas of Ibadan, in southwest Nigeria. Insecticide susceptibility to pyrethroids, organophosphates, carbamates and organochlorines was assessed using World Health Organization (WHO) bioassays. A subset of the mosquitoes exposed to pyrethroids and DDT was used for species and molecular form identification; kdr genotyping was determined using the TaqMan real-time polymerase chain reaction assay. The mosquitoes were resistant to pyrethroids and DDT but completely susceptible to organophosphates and carbamates. Bodija samples (n = 186) consisted of An. gambiae (91.4%) and An. coluzzii (8.1%) and included one An. coluzzii/An. gambiae hybrid specimen. All mosquitoes screened in Ojoo (n = 26) were An. gambiae. The 1014F kdr mutation was detected at frequencies of 24.5 and 5.8% in Bodija and Ojoo, respectively. No correlation was observed between kdr genotypes and resistance phenotypes. The results indicate that metabolic resistance probably plays an important role in the development of resistance and highlight the need to implement insecticide resistance management strategies.

  20. Effect of temperature and pH on carbamoylation and phosphorylation of serum cholinesterases. Theoretical interpretation of activation energies in complex reactions (United States)

    Simeon, Vera; Reiner, Elsa; Vernon, C. A.


    1. The effect of temperature and pH was studied on the kinetics of inhibition of horse serum and human serum cholinesterase by four organophosphorus compounds and five carbamates. 2. For all compounds, and at each pH and temperature, the inhibition followed the kinetics of a bimolecular reaction with the inhibitor in excess, and with a negligible concentration of the Michaelis complex. 3. The second-order rate constants (ka) for inhibition of human serum cholinesterase by one organophosphate and one carbamate increased from 5° to 40°C with an apparent activation energy of 46kJ/mol (11kcal/mol). 4. The ka constant for inhibition of horse serum cholinesterase increased with temperature from 5° to 30°C, and then decreased from 30° to 40°C. The theoretical interpretation of such an unusual effect of temperature is derived. 5. The increase of ka with pH (human serum cholinesterase) followed the dissociation curve for a single group on the enzyme (pK7.5). 6. Rate constants for decarbamoylation (k+3) were determined, and the time-course of inhibition was calculated from the ka and k+3 constants. PMID:4677141

  1. Effect of pesticide exposure on acetylcholinesterase activity in subsistence farmers from Campeche, Mexico. (United States)

    Rendón von Osten, Jaime; Epomex, Centro; Tinoco-Ojanguren, Rolando; Soares, Amadeu M V M; Guilhermino, Lucia


    The authors surveyed agricultural production methods and pesticide use among subsistence farmers (campesinos) in 4 rural communities of Campeche, Mexico. Self-reports of symptoms of poisoning resulting from occupational pesticide exposure were elicited by questionnaire (N = 121), and acetylcholinesterase (AChE) activity during insecticide use was evaluated from blood samples (N = 127). In individuals from 2 of the 4 communities, AChE activity was significantly lower (p < 0.05) than the mean of activity determined for individuals in a reference group. Results of this study show that erythrocyte AChE inhibition provides a good biomarker of exposure to organophosphate pesticides in field studies with human populations. Carbamates, particularly carbofuran, seem to be more associated with exuberant and diversified symptomatology of pesticide exposure than organophosphates. Studies in field communities where both carbamates and organophosphates are suspected to exist should include blood AChE determinations, symptomatology surveys, and socioeconomic questionnaires. The authors recommend that the Mexican National Health Ministry authorities specify additional provisions regarding the use of protective equipment and the adoption of other safety practices during field work, increase information campaigns about the risks of pesticide use and the value of safety practices, and increase programs of medical monitoring and assistance for rural communities dealing with pesticides.

  2. Dienophile-Modified Mannosamine Derivatives for Metabolic Labeling of Sialic Acids: A Comparative Study. (United States)

    Dold, Jeremias E G A; Pfotzer, Jessica; Späte, Anne-Katrin; Wittmann, Valentin


    Sialic acids play an important role in numerous cell adhesion processes and sialylation levels are known to be altered under certain pathogenic conditions such as cancer. Metabolic glycoengineering with mannosamine derivatives is a convenient way to introduce non-natural chemical reporter groups into sialylated glycoconjugates offering the opportunity to label sialic acids using bioorthogonal ligation chemistry. The labeling intensity not only depends on the rate of the ligation reaction but also on the extent to which the natural sialic acids are replaced by the modified ones, i.e. the incorporation efficiency. Here we present a comparative study of eight mannosamine derivatives featuring terminal alkenes as chemical reporter groups that can be labeled by an inverse-electron-demand Diels-Alder (DAinv) reaction. The derivatives differ in chain length as well as the type of linkage (comprising carbamates, amides, and a urea) that connects the terminal alkene to the sugar. As a general trend, increasing chain lengths result in higher DAinv reactivity and at the same time reduced incorporation efficiency. Carbamates are better accepted than amides with the same chain length; nevertheless do the latter result in more intense cell-surface staining visible in life-cell fluorescence microscopy. Finally, a urea derivative was shown to be accepted.

  3. Site-directed mutagenesis of an acetylcholinesterase gene from the yellow fever mosquito Aedes aegypti confers insecticide insensitivity. (United States)

    Vaughan, A; Rocheleau, T; ffrench-Constant, R


    Insecticide resistance is a serious problem facing the effective control of insect vectors of disease. Insensitive acetylcholinesterase (AChE) confers resistance to organophosphorus (OP) and carbamate insecticides and is a widespread resistance mechanism in vector mosquitoes. Although the point mutations that underlie AChE insensitivity have been described from Drosophila, the Colorado potato beetle, and house flies, no resistance associated mutations have been documented from mosquitoes to date. We are therefore using a cloned acetylcholinesterase gene from the yellow fever mosquito Aedes aegypti as a model in which to perform site directed mutagenesis in order to understand the effects of potential resistance associated mutations. The same resistance associated amino-acid replacements as found in other insects also confer OP and carbamate resistance to the mosquito enzyme. Here we describe the levels of resistance conferred by different combinations of these mutations and the effects of these mutations on the kinetics of the AChE enzyme. Over-expression of these constructs in baculovirus will facilitate purification of each of the mutant enzymes and a more detailed analysis of their associated inhibition kinetics.

  4. Evidence for inhibition of cholinesterases in insect and mammalian nervous systems by the insect repellent deet

    Directory of Open Access Journals (Sweden)

    Dimitrov Mitko


    Full Text Available Abstract Background N,N-Diethyl-3-methylbenzamide (deet remains the gold standard for insect repellents. About 200 million people use it every year and over 8 billion doses have been applied over the past 50 years. Despite the widespread and increased interest in the use of deet in public health programmes, controversies remain concerning both the identification of its target sites at the olfactory system and its mechanism of toxicity in insects, mammals and humans. Here, we investigated the molecular target site for deet and the consequences of its interactions with carbamate insecticides on the cholinergic system. Results By using toxicological, biochemical and electrophysiological techniques, we show that deet is not simply a behaviour-modifying chemical but that it also inhibits cholinesterase activity, in both insect and mammalian neuronal preparations. Deet is commonly used in combination with insecticides and we show that deet has the capacity to strengthen the toxicity of carbamates, a class of insecticides known to block acetylcholinesterase. Conclusion These findings question the safety of deet, particularly in combination with other chemicals, and they highlight the importance of a multidisciplinary approach to the development of safer insect repellents for use in public health.

  5. Carbonic anhydrase promotes the absorption rate of CO2 in post-combustion processes. (United States)

    Vinoba, Mari; Bhagiyalakshmi, Margandan; Grace, Andrews Nirmala; Kim, Dae Hoon; Yoon, Yeoil; Nam, Sung Chan; Baek, Il Hyun; Jeong, Soon Kwan


    The rate of carbon dioxide (CO2) absorption by monoethanol amine (MEA), diethanol amine (DEA), N-methyl-2,2'-iminodiethanol (MDEA), and 2-amino-2-methyl 1-propanol (AMP) solutions was found to be enhanced by the addition of bovine carbonic anhydrase (CA), has been investigated using a vapor-liquid equilibrium (VLE) device. The enthalpy (-ΔHabs) of CO2 absorption and the absorption capacities of aqueous amines were measured in the presence and/or absence of CA enzyme via differential reaction calorimeter (DRC). The reaction temperature (ΔT) under adiabatic conditions was determined based on the DRC analysis. Bicarbonate and carbamate species formation mechanisms were elucidated by (1)H and (13)C NMR spectral analysis. The overall CO2 absorption rate (flux) and rate constant (kapp) followed the order MEA > DEA > AMP > MDEA in the absence or presence of CA. Hydration of CO2 by MDEA in the presence of CA directly produced bicarbonate, whereas AMP produced unstable carbamate intermediate, then underwent hydrolytic reaction and converted to bicarbonate. The MDEA > AMP > DEA > MEA reverse ordering of the enhanced CO2 flux and kapp in the presence of CA was due to bicarbonate formation by the tertiary and sterically hindered amines. Thus, CA increased the rate of CO2 absorption by MDEA by a factor of 3 relative to the rate of absorption by MDEA alone. The thermal effects suggested that CA yielded a higher activity at 40 °C.

  6. Trapping of muscle relaxant methocarbamol degradation product by complexation with copper(II) ion: Spectroscopic and quantum chemical studies (United States)

    Mansour, Ahmed M.; Shehab, Ola R.


    Structural properties of methocarbamol (Mcm) were extensively studied both experimentally and theoretically using FT IR, 1H NMR, UV-Vis., geometry optimization, Mulliken charge, and molecular electrostatic potential. Stability arises from hyper-conjugative interactions, charge delocalization and H-bonding was analyzed using natural bond orbital (NBO) analysis. Mcm was decomposed in ethanol/water mixture at 80 °C to guaifenesin [(RS)-3-(2-methoxyphenoxy)propane-1,2-diol] and carbamate ion [NH2COO-], where the degradation mechanism was explained by trapping the carbamate ion via the complexation with copper(II) ion. The structure of the isolated complex ([Cu(NH2COO)2(H2O)]ṡ4H2O) was elucidated by spectral, thermal, and magnetic tools. Electronic spectra were discussed by TD-DFT and the descriptions of frontier molecular orbitals and the relocations of the electron density were determined. Calculated g-tensor values showed best agreement with experimental values from EPR when carried out using both the B3LYP and B3PW91 functional.

  7. Potent 5-nitrofuran derivatives inhibitors of Trypanosoma cruzi growth: Electrochemical, spectroscopic and biological studies (United States)

    Maria Aravena, C.; Claudio Olea, A.; Cerecetto, Hugo; González, Mercedes; Maya, Juan Diego; Rodríguez-Becerra, Jorge


    Cyclic voltammetry and electron spin resonance techniques were used in the investigation of several potential antiprotozoal containing thiosemicarbazone and carbamate nitrofurans. In the electrochemical behaviour, a self-protonation process involving the nitro group was observed. The reactivity of the nitro anion radical for these derivatives with glutathione, a biological relevant thiol, was also studied in means of cyclic voltammetry. These studies demonstrated that glutathione could react with radical species from 5-nitrofuryl system. Furthermore, from the voltammetric results, some parameters of biological significance as E71 (indicative of the biological nitro anion radical formation), and K (thermodynamic indicator the of oxygen redox cycling) have been calculated. We also evaluated the stability of the nitro anion radical in terms of the dimerization constant ( kd). The nitrofuran-free radicals from cyclic voltammetry were characterized by electron spin resonance. A clear dependence between both the thiosemicarbazone or carbamate substructure and the length of the linker, furyl- or furylpropenyl-spacer, and the delocalization of the unpaired electron was observed. Through of biological assays we obtained important parameters that account for the selective anti-trypanosomal activity of these derivatives. The trypomastigote viability study showed that all derivatives are as active as in the epimastigote form of the parasite in a doses dependent manner.

  8. Quantitative analysis on CO2 absorption and desorption in monoethanolamine (MEA) solution by using 13C NMR%13C NMR定量分析一乙醇胺(MEA)与CO2的吸收和解吸特性

    Institute of Scientific and Technical Information of China (English)

    郭超; 陈绍云; 陈思铭; 张永春


    13C NMR是一种有效的测定有机胺与CO2反应过程中离子浓度变化的检测手段。本文采用13C NMR分析了一乙醇胺(MEA)吸收与解吸CO2过程,吸收与解吸实验温度分别在313K和393K下进行。结果表明,吸收CO2过程中生成了MEA氨基甲酸盐、质子胺MEAH+与HCO3-/CO32-,并且CO2与MEA反应时先生成MEA氨基甲酸盐,当溶液吸收的CO2担载量达到0.455molCO2/mol 胺时,才产生HCO3-/CO32-离子。在MEA吸收CO2过程中,MEA氨基甲酸盐的摩尔分数先增加后减少。在解吸过程中,MEA氨基甲酸盐的摩尔分数同样先增加后减少。HCO3-/CO32-在解吸过程中很容易就能被解吸,而生成的MEA氨基甲酸盐中大约有75%在解吸过程中并没有被解吸。%13C NMR spectroscopy is a suitable analytical method to get quantitative information on the species distribution in aqueous amine solutions loaded with carbon dioxide (CO2). 13C NMR is used for quantitative analysis on CO2 absorption and desorption in monoethanolamine (MEA) solution. Temperatures of absorption and desorption experiments are 313K and 393K,respectively. From 13C NMR spectroscopy,it is found that the main MEA species under the absorption conditions studied are free amine,protonated amine,MEA carbamate,and HCO3-/CO32-. At absorption step,MEA carbamate is produced first,when CO2 loading is getting higher to 0.455mol CO2/mol amine in this experiment,HCO3-/CO32- appears. The mole fraction of the MEA carbamate increases first with absorption time,reaches their maximum,and then decreases. The mole fraction of HCO3-/CO32-consistently increases with the increase of absorption time. At the desorption step,the mole fraction of MEA carbamate increases at early stage,reaches a maximum,and then decreases up to the end. After the desorption process,all HCO3-/CO32-can be stripped while about 75%of MEA carbamate still exist in the MEA solution.

  9. Update on resistance status of Anopheles gambiae s.s. to conventional insecticides at a previous WHOPES field site, "Yaokoffikro", 6 years after the political crisis in Côte d'Ivoire

    Directory of Open Access Journals (Sweden)

    Koffi Alphonsine A


    Full Text Available Abstract Background At Yaokoffikro field site near Bouaké, in central Côte d'Ivoire, a group of experimental huts built in 1996 served over many years for the evaluation of insecticides against highly resistant mosquitoes. Breeding sites of mosquitoes and selection pressure in the area were maintained by local farming practices until a war broke out in September 2002. Six years after the crisis, we conducted bioassays and biochemical analysis to update the resistance status of Anopheles gambiae s.s. populations and detect other potential mechanisms of resistance that might have evolved. Methods An. gambiae s.s. larvae from Yaokoffikro were collected in breeding sites and reared to adults. Resistance status of this population to insecticides was assessed using WHO bioassay test kits for adult mosquitoes with seven insecticides: two pyrethroids, a pseudo-pyrethroid, an organochloride, two carbamates and an organophosphate. Molecular and biochemical assays were carried out to identify the L1014F kdr and ace-1R alleles in individual mosquitoes and to detect potential increase in mixed function oxidases (MFO, non-specific esterases (NSE and glutathione S-transferases (GST activity. Results High pyrethroids, DDT and carbamate resistance was confirmed in An. gambiae s.s. populations from Yaokoffikro. Mortality rates were less than 70% with pyrethroids and etofenprox, 12% with DDT, and less than 22% with the carbamates. Tolerance to fenitrothion was observed, with 95% mortality after 24 h. PCR analysis of samples from the site showed high allelic frequency of the L1014F kdr (0.94 and the ace-1R (0.50 as before the crisis. In addition, increased activity of NSE, GST and to a lesser extent MFO was found relative to the reference strain Kisumu. This was the first report detecting enhanced activity of these enzymes in An. gambiae s.s from Yaokoffikro, which could have serious implications in detoxification of insecticides. Their specific roles in

  10. The side effect of Paecilomyces fumosoroseusapplication on the black ant, Dolichoderus thoracicus, the predator of Helopeltis antoniiand cocoa pod borer

    Directory of Open Access Journals (Sweden)

    Endang Sulistyowai


    Full Text Available Paecilomyces fumosoroseuswas known as one of the effective biological agents of cocoa pod borer and Helopeltis antonii. To find out the side effect of application of P. fumosoroseuson black ant, Dolichoderus thoracicus, a series of observations were carried out at the Laboratory of Pest and Diseases Indonesian Coffee and Cocoa Research Institute (ICCRI and in a cocoa plantation of Glenmore, Banyuwangi district, since June until October, 2004. Laboratory research used four concentrations of P. fumosoroseusnamely 105, 106, 107 and 108 spores/ml, while in the field used concentration 2, 4, 6, 8 g dry spores/ml. Each trial as compared with spraying of carbamate and synthetic pyrethroid insecticides as control and untreated This research was designed by randomized block design and four replications. The results showed that in the laboratory, direct spraying suspension of P. fumosoroseuskilled black ant between 20—39% which infected fungi about 2.5—12.5%. The relationship between log of spores concentration of P. fumosoroseus and probit of ant mortality followed the regression equation Y = 3.653 + 0.097 X with LC 50 was 8 x 10 13 spore/ml. The period needed to kill a half of ant population at the laboratory (LT 50 at concentration 107 spores/ml followed the regression equation Y = 1.851 + 1.522 X, with LT50 is 12,01 days. The effect of pyrethroid and carbamate insecticide on ants mortality were 91.25% and 98.75% respectively. In the field, the effect of P. fumosoroseusspray on black ant population was very low, with the percentage of ant mortality at cocoa leaf nest were 0.25–0.46% and at cocoa leaf nest in plastic bag were 0.06–0.21%, while carbamate and pyrethroid synthetic effect were 37.35% and 52.37% at cocoa leaf nest, and 19.15% and 46.67% at cocoa leaf nest in plastic bags. Key words : Cocoa, capsid, Helopeltis antonii, biological control, biological agents, Paecilomyces fumosoroseus, Dolichoderus tharacicus.

  11. Strain-related effects of fenbendazole treatment on murine experimental autoimmune encephalomyelitis. (United States)

    Ramp, A A; Hall, C; Orian, J M


    Parasitic infections are a concern in animal facilities, in view of their influence on physiological processes and the immune status of animals. Pinworms are effectively controlled with the anthelminthic fenbendazole (FBZ, [5-(phenylthio)-1H-benzamidazol-2-yl]carbamic acid methyl ester; C(15)H(13)N(3)O(2)S); however, questions remain as to whether prolonged FBZ exposure alters the disease course in specific experimental models, such as those pertaining to the immune system. We report that a three-month regimen of FBZ-medicated feed severely affected the onset and disease severity of murine experimental autoimmune encephalomyelitis (EAE), a disease that mimics multiple sclerosis. Differences were recorded between mouse strains used. Our data suggest that where the use of FBZ is mandatory, its full effect should be verified on the particular EAE variant adopted by the laboratory.

  12. Research Progress on the Indirect Hydrogenation of Carbon Dioxide to Methanol. (United States)

    Du, Xian-Long; Jiang, Zheng; Su, Dang Sheng; Wang, Jian-Qiang


    Methanol is a sustainable source of liquid fuels and one of the most useful organic chemicals. To date, most of the work in this area has focused on the direct hydrogenation of CO2 to methanol. However, this process requires high operating temperatures (200-250 °C), which limits the theoretical yield of methanol. Thus, it is desirable to find a new strategy for the efficient conversion of CO2 to methanol at relatively low reaction temperatures. This Minireview seeks to outline the recent advances on the indirect hydrogenation of CO2 to methanol. Much emphasis is placed on discussing specific systems, including hydrogenation of CO2 derivatives (organic carbonates, carbamates, formates, cyclic carbonates, etc.) and cascade reactions, with the aim of critically highlighting both the achievements and remaining challenges associated with this field.

  13. A Versatile Synthesis of 1,3,5-Triamino-2,4,6-Trinitrobenzene (TATB)

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, A R; Pagoria, P F; Schmidt, R D; Coburn, M D; Lee, G S; Hsu, P C


    A safe and versatile synthesis of high-purity 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) based on vicarious nucleophilic substitution (VNS) chemistry has now been achieved. The starting material can be selected from a variety of inexpensive nitroarenes obtained from commercial suppliers (4-nitroaniline, picric acid) or U.S. stockpiles (ammonium picrate, TNT). The use of picric acid and ammonium picrate (Explosive D) is preferred as both compounds are directly converted to picramide in the presence of ammonium salts (diammonium hydrogen phosphate, ammonium carbamate) in sulfolane at elevated temperature. The picramide resulting from this process is directly converted to TATB using an optimized VNS reaction employing inexpensive hydroxylamine as the nucleophilic aminating reagent. A crucial element in our synthesis is a novel and efficient purification of TATB.

  14. Model study on the clinical signs and residue concentrations of sublethal carbofuran poisoning in birds. (United States)

    Lehel, J; Laczay, P; Déri, J; Darin, E G; Budai, P


    The incidence of fatal poisoning of birds of prey caused by carbofuran has increased markedly in Hungary since 2007. An experimental model with broiler chickens was used to study clinical signs of sublethal carbofuran poisoning in birds and to measure the residue concentrations of carbamate in tissues after exposure. Eight chickens were treated with a carbofuran-containing insecticide orally by gastric tube at a single dose of 2.5 mg/kg body weight, and clinical signs of poisoning were observed. Gas chromatography was used to determine carbofuran concentrations in the blood, muscle, and liver samples, and in stomach contents. Poisoning was characterized by typical muscarinic and nicotinic clinical signs without mortality. Carbofuran in the stomach and edible tissues of acutely poisoned birds may lead to secondary poisoning of predators and may also present risks to human health.

  15. Attenuation of cellular antioxidant defense mechanisms in kidney of rats intoxicated with carbofuran. (United States)

    Kaur, Bhupindervir; Khera, Alka; Sandhir, Rajat


    Carbofuran, an anticholinestrase carbamate, is commonly used as an insecticide. Its toxic effect on kidney is less established. The present study was designed to investigate the effect of carbofuran on kidneys and to understand the mechanism involved in its nephrotoxicity. Male Wistar rats were divided into two groups of eight animals each; control animals received sunflower oil (vehicle) and carbofuran exposed animals were treated with carbofuran (1 mg/kg body weight) orally for 28 days. At the end of the treatment, significant increase was observed in urea and creatinine levels in serum along with the inhibition of acetylcholinesterase, suggesting nephrotoxicity. The antioxidant defense system of animals treated with carbofuran was altered in terms of increased lipid peroxidation, reduced glutathione, and total thiols and decreased activity of antioxidant enzymes (superoxide dismutase and catalase). The results indicate that carbofuran is nephrotoxic and increased oxidative stress appears to be involved in its nephrotoxic effects.

  16. Electrochemical nonenzymatic sensor based on CoO decorated reduced graphene oxide for the simultaneous determination of carbofuran and carbaryl in fruits and vegetables. (United States)

    Wang, MingYan; Huang, JunRao; Wang, Meng; Zhang, DongEn; Chen, Jun


    A novel nonenzymatic sensor based on cobalt (II) oxide (CoO)-decorated reduced graphene oxide (rGO) was developed for the detection of carbofuran (CBF) and carbaryl (CBR). Two well-defined and separate differential pulse voltammetric peaks for CBF and CBR were obtained with the CoO/rGO sensor in a mixed solution, making the simultaneous detection of both carbamate pesticides possible. The nonenzymatic sensor demonstrated a linear relationship over a wide concentration range of 0.2-70 μM (R=0.9996) for CBF and 0.5-200 μM (R=0.9995) for CBR. The lower detection limit of the sensor was 4.2 μg/L for CBF and 7.5 μg/L for CBR (S/N=3). The developed sensor was used to detect CBF and CBR in fruit and vegetable samples and yielded satisfactory results.

  17. Photocatalytic degradation of carbofuran in TiO2 aqueous solution: kinetics using design of experiments and mechanism by HPLC/MS/MS. (United States)

    Yang, Hai; Zhou, Shuolin; Liu, Huajie; Yan, Weiwei; Yang, Liping; Yij, Bing


    The photocatalytic degradation kinetics of carbofuran was optimized by central composite design based on response surface methodology for the first time. Three variables, TiO2 concentration, initial pH value and the concentration of carbofuran, were selected to determine the dependence of degradation efficiencies on independent variables. Response surface methodology modeling results indicated that the degradation efficiency of carbofuran was highly affected by the initial pH value and the concentration of carbofuran. Then nine degradation intermediates were detected by HPLC/MS/MS. The Frontier Electron Densities of carbofuran were calculated to predict the active sites on carbofuran attacked by hydroxyl radicals and photoholes. Point charges were used to elucidate the chemisorption pattern on TiO2 catalysts during the photocatalytic process. By combining the experimental results and calculation data, the photocatalytic degradation pathways of carbofuran were proposed, including the addition of hydroxyl radicals and the cleavage of the carbamate side chain.

  18. Degradation of carbofuran by ozonation. (United States)

    Suneethi, S; Joseph, Kurian


    Degradation of commercial grade carbofuran (2, 3 dihydro-2, 2-dimethyl-7 benzo furanyl-N-methyl carbamate) in aqueous solution by ozone oxidation was investigated using bench scale experiments. The degradation rate was strongly influenced by the ozone dosage, pH, initial concentration of carbofuran and contact time of ozonation. Carbofuran solution of 200ppm concentration was degraded by 79% within 10 minutes consuming 87 mg of ozone at pH 4. The associated TOC reduction was observed to be 53%. Ammonium (20 mg/L) and nitrate (30 mg/L) ions were detected in the effluent as degradation products of ozonation. The results support the effectiveness of ozonation for degradation of organic pesticides such as carbofuran.

  19. Wine features related to safety and consumer health: an integrated perspective. (United States)

    Pozo-Bayón, M Ángeles; Monagas, María; Bartolomé, Begoña; Moreno-Arribas, M Victoria


    This review presents a global view of the current situation of the scientific knowledge about aspects of wine with possible repercussions (positive or negative) on consumer health and wine safety. The presence in wine of some potential harmful compounds such as phytosanitary products, trace metal compounds, sulfites, and some toxics of microbial origin, such as ochratoxin A, ethyl carbamate, and biogenic amines, is discussed. The different strategies and alternative methodologies that are being carried out to reduce or to avoid the presence of these substances in wines are also discussed. In recent years much work has focused on establishing the scientific explanations for the positive biological effects of some wine compounds. In this review, we also examine the latest knowledge regarding wine and health, focusing on two types of compounds that have been related to the positive effects of moderate wine consumption, such as phenolic compounds and bioactive peptides.

  20. Rapid quantification of cyanamide by ultra-high-pressure liquid chromatography in fertilizer, soil or plant samples. (United States)

    Nagumo, Yoshifumi; Tanaka, Kazuya; Tewari, Kaushal; Thiraporn, Khwankaew; Tsuchida, Toru; Honma, Toshimitsu; Ohtake, Norikuni; Sueyoshi, Kuni; Takahashi, Yoshihiko; Ohyama, Takuji


    A rapid and simple method for determination of cyanamide in fertilizer, soil and plants has been developed. In this method, cyanamide is extracted with 2% acetic acid and the extract separated by centrifugation. It is then purified by passing through a membrane filter. The extract was derivatized with 6-aminoquinolyl-N-hydroxysuccinimidyl-carbamate and the derivatized compound separated by ultra-high-pressure liquid chromatography. It is then detected with a UV detector at 260 nm by the same method as is used for amino acid analysis. The proposed method is fast, simple and cheap and also has good selectivity and sensitivity for the determination of cyanamide in a wide range of biotic and abiotic materials.

  1. Oxygen-Binding Characteristics of Hemoglobins from Hypoxia and Hypercapnia Tolerant African Mole Rats

    DEFF Research Database (Denmark)

    Weber, Roy E.; Jarvis, Jennifer U. M; Fago, Angela;


    ) originating from a range of different biomes and soil types. The study shows no evidence for distinguishing interspecific differences in hematological characters (e.g. DPG and Hb levels and isoHb differentiation). Additionally small differences observed in Hb’s intrinsic O2 affinity and in the effects of pH...... transport of respiratory gases, we analysed hematological characters, as well as the Hb-O2 affinities and their sensitivities to pH (the Bohr effect), CO2, temperature and to the major red cell allosteric effector, DPG, in 4 eusocial and 2 strictly-solitary species of African mole rats (family Bathyergidae......, DPG and temperature were not clearly correlated with sociality and soil-type. However, it reveals palpable, species-specific reductions in the specific (pH-independent) effect of CO2 on Hb-O2 affinity (carbamate formation) compared to other mammalian Hbs, which would be adaptive in safeguarding...

  2. Thermoset Shape-Memory Polyurethane with Intrinsic Plasticity Enabled by Transcarbamoylation. (United States)

    Zheng, Ning; Fang, Zizheng; Zou, Weike; Zhao, Qian; Xie, Tao


    Thermoset polymers are known for their superior thermomechanical properties, but the chemical crosslinking typically leads to intractability. This is reflected in the great differences between thermoset and thermoplastic shape-memory polymers; the former exhibit a robust shape memory but are not capable of redefining the permanent shape. Contrary to current knowledge, we reveal here that a classical thermoset shape-memory polyurethane is readily capable of permanent reshaping (plasticity) after a topological network rearrangement that is induced by transcarbamoylation. By employing the Jianzhi technique (also known as kirigami), unexpected shape-shifting versatility was observed for this otherwise classical material. As the essential carbamate moiety in polyurethanes is one of the most common polymer building units, we anticipate that our finding will have significant benefits beyond shape shifting.

  3. Application of carbon dioxide towards the development of smart materials, green reaction schemes and metallic nanoparticle synthesis (United States)

    Mohammed, Fiaz S.

    Global carbon dioxide (CO2) emissions have steadily risen over the last 50 years, with 34 billion tons of CO2 released in 2009 alone. Its potential as a greenhouse gas has negatively affected of our lives and environment by the resulting ocean acidification and climate change. To mitigate atmospheric CO2, various strategies have been implemented for CO2 separation, capture, storage and use as a chemical feedstock. The use of CO2 in various chemical industries is attractive as its non-flammable, non-toxic, and relatively inert properties have made it an inherently safer alternative to traditional organic solvents, as well as, a greener carbon feedstock. Also, the accessible critical properties, appreciable critical density, high diffusivity and tunable thermophysical properties make liquid and supercritical CO2 an attractive solvent for industrial applications. In recent years, significant progress has been made in the field of tunable solvent media by employing the reversible reaction of CO2 with amines to produce carbamates. This class of compounds possesses ionic properties that are significantly different from their amines resulting in a non-ionic to ionic switching mechanism that provides for switchable solvent properties, reversible surfactants, low molecular weight organogelators and stimuli responsive materials. The focus of this dissertation is therefore the implementation of the reversible CO2—amine reaction for the formation of smart surfaces, greener amine protection mechanisms, and cationic metallic nanoparticle synthesis. Chapter 2 of this dissertation demonstrates the reversible reaction of CO2 with amine-containing self-assembled monolayers to yield "smart" surfaces that undergo a reversible change in structure, charge, and wettability upon reaction with CO2. The formation carbamate esters are also a widely implemented mechanism for amine protection during organic synthesis. However, traditional methods of protection incur increased solvent use and

  4. Inactivation of urease by catechol: Kinetics and structure. (United States)

    Mazzei, Luca; Cianci, Michele; Musiani, Francesco; Lente, Gábor; Palombo, Marta; Ciurli, Stefano


    Urease is a Ni(II)-containing enzyme that catalyzes the hydrolysis of urea to yield ammonia and carbamate at a rate 10(15) times higher than the uncatalyzed reaction. Urease is a virulence factor of several human pathogens, in addition to decreasing the efficiency of soil organic nitrogen fertilization. Therefore, efficient urease inhibitors are actively sought. In this study, we describe a molecular characterization of the interaction between urease from Sporosarcina pasteurii (SPU) and Canavalia ensiformis (jack bean, JBU) with catechol, a model polyphenol. In particular, catechol irreversibly inactivates both SPU and JBU with a complex radical-based autocatalytic multistep mechanism. The crystal structure of the SPU-catechol complex, determined at 1.50Å resolution, reveals the structural details of the enzyme inhibition.

  5. Superior DeNOx activity of V2O5–WO3/TiO2 catalysts prepared by deposition–precipitation method

    DEFF Research Database (Denmark)

    Putluru, Siva Sankar Reddy; Schill, Leonhard; Gardini, Diego


    electron microscopy, H2-temperature programmed reduction and NH3-temperature programmed desorption. The catalysts exhibited only crystalline TiO2 phases with the active metal and promoter in highly dispersed or amorphous state. The 3 wt% V2O5–10 wt% WO3/TiO2 catalyst prepared by DP using ammonium carbamate......V2O5–WO3/TiO2 catalysts were prepared by incipient wetness impregnation and deposition–precipitation (DP) methods. The catalysts were characterized by N2 physisorption, X-ray powder diffraction, Fourier transform infra red spectroscopy, electron paramagnetic resonance spectroscopy, transmission...... as a precipitating agent was found to be the most active and selective to N2. The superior activity of the catalyst can be ascribed to the altered acidic and redox properties of vanadium. The catalysts did not show increased potassium resistance with the change in preparation method or with increasing vanadium...

  6. Synthesis and properties of new bolaform and macrocyclic galactose-based surfactants obtained by olefin metathesis. (United States)

    Satgé, Céline; Granet, Robert; Verneuil, Bernard; Champavier, Yves; Krausz, Pierre


    A series of galactose-based surfactants with various structures likely to display new interesting properties were synthesized. Four monocatenary surfactants were elaborated by microwave-assisted galactosylation of undecanol or 10-undecenol. These compounds were slightly soluble in water. Their tensioactive properties were determined at 45 degrees C. Olefin metathesis was used to synthesize the two single-chain bolaforms from undec-10-enyl galactopyranosides; two pseudomacrocyclic bolaforms were prepared by grafting two carbamates at O-4 and O-4' sugar positions of the single-chain bolaforms. These four surfactants are insoluble in water and undergo monolayer compression. Cyclization of these bolaforms by olefin metathesis led to macrocyclic surfactant analogues of archaeobacterial membrane components.

  7. Effects of pesticides on songbird productivity in conjunction with pecan cultivation in southern Georgia: A multiple-exposure experimental design (United States)

    Patnode, K.A.; White, D.H.


    A prototypic experimental design was used to assess sublethal effects of multiple and varied organophosphates and carbamates on reproduction in birds. The design allowed for classification of pesticide exposure according to toxicity of applied compounds and type and frequency of applications. Daily survival rates (DSRs) of nests, eggs, and nestlings were determined for northern mockingbirds (Mimus polyglottos), brown thrashers (Toxostoma rufum), and northern cardinals (Cardinalis cardinalis) nesting along edges of pecan orchards and row crops in southern Georgia [USA]. Egg and nestling DSRs for all species combined varied inversely (P 0.05) among three exposure levels. Brain cholinesterase activities were age-dependent and substantiated adult, but not nestling, exposure. Results suggest that increasing exposure to pesticides may reduce songbird productivity.

  8. Collateral damage: rapid exposure-induced evolution of pesticide resistance leads to increased susceptibility to parasites. (United States)

    Jansen, Mieke; Stoks, Robby; Coors, Anja; van Doorslaer, Wendy; de Meester, Luc


    Although natural populations may evolve resistance to anthropogenic stressors such as pollutants, this evolved resistance may carry costs. Using an experimental evolution approach, we exposed different Daphnia magna populations in outdoor containers to the carbamate pesticide carbaryl and control conditions, and assessed the resulting populations for both their resistance to carbaryl as well as their susceptibility to infection by the widespread bacterial microparasite Pasteuria ramosa. Our results show that carbaryl selection led to rapid evolution of carbaryl resistance with seemingly no cost when assessed in a benign environment. However, carbaryl-resistant populations were more susceptible to parasite infection than control populations. Exposure to both stressors reveals a synergistic effect on sterilization rate by P. ramosa, but this synergism did not evolve under pesticide selection. Assessing costs of rapid adaptive evolution to anthropogenic stress in a semi-natural context may be crucial to avoid too optimistic predictions for the fitness of the evolving populations.

  9. [Determination of insecticide-resistance and resistance mechanisms of Blattella germanica (Dictyoptera: Blattellidae)]. (United States)

    Díaz, Pantoja Cristina; Alvarez Gavilán, Yudelmis; de Armas Rodríguez, Yaxsier; Bisset Lazcano, Juan A


    In this paper, the level of resistance to four insecticides of 3 Blatella germanica strains collected from various places in the City of Havana province was evaluated. These strains were resistant to two pyrethroids (cypermethrin and lambda-cyalothrine) and to organophosphorate malathion but susceptible to carbamate propoxur. The values of alpha and beta esterases, acetylcholinesterase and gluthatione-S-transferase were estimated in three strains involved in the study. The results of the study showed high esterase activity in all the strains, mainly beta esterases and two of the three strains presented with high gluthation-S-transferase enzyme. No changes in acetylcholinesterase were demonstrated in relation to the reference strain. The association of levels of resistance to insecticides, the possible resistance mechanisms in each strain and the results of the enzymatic activity were also analyzed.

  10. Atomic basis for therapeutic activation of neuronal potassium channels

    DEFF Research Database (Denmark)

    Kim, Robin Y; Yau, Michael C; Galpin, Jason D


    chemical interactions required for retigabine action. Introduction of a non-natural isosteric H-bond-deficient Trp analogue abolishes channel potentiation, indicating that retigabine effects rely strongly on formation of a H-bond with the conserved pore Trp. Supporting this model, substitution...... with fluorinated Trp analogues, with increased H-bonding propensity, strengthens retigabine potency. In addition, potency of numerous retigabine analogues correlates with the negative electrostatic surface potential of a carbonyl/carbamate oxygen atom present in most KCNQ activators. These findings functionally...... pinpoint an atomic-scale interaction essential for effects of retigabine and provide stringent constraints that may guide rational improvement of the emerging drug class of KCNQ channel activators....

  11. An efficient synthesis of loline alkaloids (United States)

    Cakmak, Mesut; Mayer, Peter; Trauner, Dirk


    Loline (1) is a small alkaloid that, in spite of its simple-looking structure, has posed surprising challenges to synthetic chemists. It has been known for more than a century and has been the subject of extensive biological investigations, but only two total syntheses have been achieved to date. Here, we report an asymmetric total synthesis of loline that, with less then ten steps, is remarkably short. Our synthesis incorporates a Sharpless epoxidation, a Grubbs olefin metathesis and an unprecedented transannular aminobromination, which converts an eight-membered cyclic carbamate into a bromopyrrolizidine. The synthesis is marked by a high degree of chemo- and stereoselectivity and gives access to several members of the loline alkaloid family. It delivers sufficient material to support a programme aimed at studying the complex interactions between plants, fungi, insects and bacteria brokered by loline alkaloids.

  12. [Survey of pesticide residues in imported spices and herbs (1997.4-2011.3)]. (United States)

    Kobayashi, Maki; Ohtsuka, Kenji; Tamura, Yasuhiro; Tomizawa, Sanae; Kinoshita, Teruaki; Kamijo, Kyoko; Iwakoshi, Keiko; Sato, Chizuko; Nagayama, Toshihiro; Takano, Ichiro


    A survey of pesticide residues in 313 samples of imported spices and herbs on the Tokyo market from April 1997 to March 2011 was carried out. Thirty-seven kinds of pesticides, including organophosphorus, organochlorine, pyrethroid, carbamate and others, were detected between levels of trace (below 0.01 ppm) and 3.3 ppm from 64 samples. The rate of detection was highest in peel (100%) followed by stem (66.7%), fruit (34.5%), bark (33.3%), flower (31.3%) and leaf (14.7%). No residues were detected in root, seed or whole grass. Organochlorine pesticides were detected in all plant parts. The insecticides were detected in products from all production areas, suggesting that their use is common. Residue levels of these pesticides were calculated as less than 1% of their ADI values, based on the daily intake of spices and herbs. Therefore, these spices and herbs should be safe when consumed in customary amounts.

  13. [3,3]-sigmatropic rearrangements of fluorinated allyl (Thio)cyanates - a tool for the synthesis of fluorinated (Thio)ureas. (United States)

    Ramb, Daniel C; Kost, Lisa; Haufe, Günter


    The first (thio)cyanate to iso(thio)cyanate rearrangements based on 2-fluoroallylic alcohols are presented. Long-chain 2-fluoroallylic alcohols were converted to corresponding N-unsubstituted carbamates by treatment with trichloroacetyl isocyanate. Dehydration using trifluoroacetic anhydride in the presence of triethylamine formed intermediate allylic cyanates, which immediately underwent sigmatropic rearrangement to fluorinated allyl isocyanates. Without isolation the latter delivered fluorinated ureas by addition of amines. The thiocyanate to isothiocyanate rearrangements started from the same fluorinated allylic alcohols, which were first converted to mesylates. Heating in THF with potassium thiocyanate led to fluorinated allyl isothiocyanates, via [3,3]-sigmatropic rearrangement of intermediate allyl thiocyanates. The formed products were further reacted with amines to fluorinated thioureas.

  14. Synthesis of Norcarbovir Analogues, the First Examples of Cyclobutene Nucleosides Unsubstituted at the Vinylic Position. (United States)

    Gourdel-Martin, Marie-Edith; Huet, François


    Two cyclobutene nucleosides, 27 and 29, analogous to the yet unknown norcarbovir, and with adenine and hypoxanthine as the base moieties, respectively, were synthesized starting from cis-3-cyclobutene-1,2-dicarboxylic anhydride (6). Its reduction to lactone 9 followed by reaction with ammonia and then Hofmann rearrangement led to cyclic carbamate 15 which was the key intermediate of these syntheses. Its tert-butoxycarbonyl derivative 17 led to the ring opening of the heterocyclic moiety at low temperature. Compound 18 was thus obtained, and the successive benzylation and then treatment with hydrochloric acid yielded hydrochloride 21. Construction of bases was achieved in satisfying overall yields provided that mild experimental conditions from 21 to 27 or 29 were used to restrict the unwanted electrocyclic ring opening. Nitropyrimidine 31 was also prepared from 21 via the intermediate 23.

  15. Photocatalysis of fenoxycarb over silver-modified zeolites. (United States)

    Ahern, John; Kanan, Sofian; Sara, Ziad; Job, Thomas; Alnaizy, Raafat; Abu Farha, Nedal; Patterson, Howard


    Two samples of silver doped into zeolite Y were prepared and characterized. ICP and SEM-EDS analysis indicate that the AgY1 sample contains twice the amount of silver compared to the AgY2 sample. Solid state luminescence spectroscopy shows variations in the emission modes of the site-selective luminescence where various luminophores might be excited upon selecting the proper excitation energy. The selected material effectively decomposed the pesticide fenoxycarb in aqueous solution. The photodecomposition of fenoxycarb reached 80 % upon irradiation for 60 min in the presence of the AgY1 catalyst. 2-(4-Phenoxy-phenoxy)ethyl] carbamic acid (1) and 1-amine-2-(phenoxy-4-ol) ethane (2) were identified as products for both uncatalyzed solution and the catalyzed fenoxycarb with AgY2 catalyst. Whereas, compound (2) was the only product identified in the catalyzed reaction with AgY1.

  16. Herbicide-resistance conferred by expression of a catalytic antibody in Arabidopsis thaliana. (United States)

    Weiss, Yael; Shulman, Avidor; Ben Shir, Irina; Keinan, Ehud; Wolf, Shmuel


    Engineering herbicide resistance in crops facilitates control of weed species, particularly those that are closely related to the crop, and may be useful in selecting lines that have undergone multiple transformation events. Here we show that herbicide-resistant plants can be engineered by designing an herbicide and expressing a catalytic antibody that destroys the herbicide in planta. First, we developed a carbamate herbicide that can be catalytically destroyed by the aldolase antibody 38C2. This compound has herbicidal activity on all three plant species tested. Second, the light chain and half of the heavy chain (Fab) of the catalytic antibody were targeted to the endoplasmic reticulum in two classes of Arabidopsis thaliana transformants. Third, the two transgenic plants were crossed to produce an herbicide-resistant F1 hybrid. The in vitro catalytic activity of the protein from F1 hybrids corroborates that catalytic antibodies can be constitutively expressed in transgenic plants, and that they can confer a unique trait.

  17. Fast and Convenient Synthesis of Amine-Terminated Polylactide as a Macroinitiator for ω-Benzyloxycarbonyl-L-Lysine-N-Carboxyanhydrides

    Directory of Open Access Journals (Sweden)

    Mingjie Ju


    Full Text Available Amine-terminated poly (L-lactide (NH2-PLLA with various chain lengths were successfully synthesized by sequential tert-butyl-N-(3-hydroxypropyl carbamate initiated bulk ring-opening polymerization (ROP of L-lactide (L-LA in the presence of Stannous(II 2-ethylhexanoate (Sn(Oct2 and deprotection of the N-tert-butoxycarbonyl (Boc group at the end of the polymer chain. The polymers obtained were characterized by FT-IR, 1H NMR, and GPC method. NH2-PLLA thus prepared was used to initiate the polymerization of ω-benzyloxycarbonyl-L-lysine-N-carboxyanhydride (Lys (Z-NCA, and the result confirmed the high nucleophilicity of the terminal amine group. This method was not only suitable for the preparation of low molecular weight NH2-PLLA, but also quite efficient in the synthesis of high molecular weight samples.

  18. Mold Resistance and Leachability of 5-Methyl Carbendazim Fungicide%5-甲基多菌灵的防霉性和抗流失性

    Institute of Scientific and Technical Information of China (English)

    崔爱玲; 黄涛; 翟炜; 程康华


    In order to develop carbendazim fungicide for wood-based products,2-carbamatebenzimidazole carbendazim (MBC) was modified to 2-carbamate-5-methyl-benzimidazole (MMBC).Mold resistance and leachability of MMBC were tested.The results showed that mold resistance of MMBC was better than pentachlorophenol sodium (Na-pcp) and leachability was improved compared with MBC.%为开发防霉效果优良的木材用防霉剂,对2-氨基甲酸甲酯苯并咪唑(多菌灵,MBC)进行改性,得到2-氨基甲酸甲酯-5-甲基苯并咪唑(MMBC).经检测MMBC处理材的防霉性和抗流失性,结果表明:MMBC的防霉性优于传统防霉剂五氯酚钠,且流失率较改性前有所降低.

  19. Aspects of carbon dioxide utilization

    Energy Technology Data Exchange (ETDEWEB)

    Omae, Iwao [Omae Research Laboratories, 335-23 Mizuno, Sayama, Saitama 350-1317 (Japan)


    Carbon dioxide reacts with hydrogen, alcohols, acetals, epoxides, amines, carbon-carbon unsaturated compounds, etc. in supercritical carbon dioxide or in other solvents in the presence of metal compounds as catalysts. The products of these reactions are formic acid, formic acid esters, formamides, methanol, dimethyl carbonate, alkylene carbonates, carbamic acid esters, lactones, carboxylic acids, polycarbonate (bisphenol-based engineering polymer), aliphatic polycarbonates, etc. Especially, the productions of formic acid, formic acid methyl ester and dimethylformamide with a ruthenium catalyst; dimethyl carbonate and urethanes with a dialkyltin catalyst; 2-pyrone with a nickel-phosphine catalyst; diphenyl carbonate with a lead phenoxide catalyst; the alternating copolymerization of carbon dioxide and epoxides with a zinc catalyst has attracted attentions as the industrial utilizations of carbon dioxide. The further development of these production processes is expected. (author)

  20. Progress towards bioorthogonal catalysis with organometallic compounds. (United States)

    Völker, Timo; Dempwolff, Felix; Graumann, Peter L; Meggers, Eric


    The catalysis of bioorthogonal transformations inside living organisms is a formidable challenge--yet bears great potential for future applications in chemical biology and medicinal chemistry. We herein disclose highly active organometallic ruthenium complexes for bioorthogonal catalysis under biologically relevant conditions and inside living cells. The catalysts uncage allyl carbamate protected amines with unprecedented high turnover numbers of up to 270 cycles in the presence of water, air, and millimolar concentrations of thiols. By live-cell imaging of HeLa cells and with the aid of a caged fluorescent probe we could reveal a rapid development of intense fluorescence within the cellular cytoplasm and therefore support the proposed bioorthogonality of the catalysts. In addition, to illustrate the manifold applications of bioorthogonal catalysis, we developed a method for catalytic in-cell activation of a caged anticancer drug, which efficiently induced apoptosis in HeLa cells.