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Sample records for pyrrole insecticide chlorfenapyr

  1. The activity of the pyrrole insecticide chlorfenapyr in mosquito bioassay: towards a more rational testing and screening of non-neurotoxic insecticides for malaria vector control.

    Science.gov (United States)

    Oxborough, Richard M; N'Guessan, Raphael; Jones, Rebecca; Kitau, Jovin; Ngufor, Corine; Malone, David; Mosha, Franklin W; Rowland, Mark W

    2015-03-24

    The rapid selection of pyrethroid resistance throughout sub-Saharan Africa is a serious threat to malaria vector control. Chlorfenapyr is a pyrrole insecticide which shows no cross resistance to insecticide classes normally used for vector control and is effective on mosquito nets under experimental hut conditions. Unlike neurotoxic insecticides, chlorfenapyr owes its toxicity to disruption of metabolic pathways in mitochondria that enable cellular respiration. A series of experiments explored whether standard World Health Organization (WHO) guidelines for evaluation of long-lasting insecticidal nets, developed through testing of pyrethroid insecticides, are suitable for evaluation of non-neurotoxic insecticides. The efficacy of WHO recommended cone, cylinder and tunnel tests was compared for pyrethroids and chlorfenapyr. To establish bioassay exposure times predictive of insecticide-treated net (ITN) efficacy in experimental hut trials, standard three-minute bioassays of pyrethroid and chlorfenapyr ITNs were compared with longer exposures. Mosquito behaviour and response to chlorfenapyr ITN in bioassays conducted at night were compared to day and across a range of temperatures representative of highland and lowland transmission. Standard three-minute bioassay of chlorfenapyr produced extremely low levels of mortality compared to pyrethroids. Thirty-minute day-time bioassay produced mortality closer to hut efficacy of chlorfenapyr ITN but still fell short of the WHO threshold. Overnight tunnel test with chlorfenapyr produced 100% mortality and exceeded the WHO threshold of 80%. The endogenous circadian activity rhythm of anophelines results in inactivity by day and raised metabolism and flight activity by night. A model which explains improved toxicity of chlorfenapyr ITN when tested at night, and during the day at higher ambient temperature, is that activation of chlorfenapyr and disruption of respiratory pathways is enhanced when the insect is more metabolically

  2. Chlorfenapyr, a Potent Alternative Insecticide of Phoxim To Control Bradysia odoriphaga (Diptera: Sciaridae).

    Science.gov (United States)

    Zhao, Yunhe; Wang, Qiuhong; Wang, Yao; Zhang, Zhengqun; Wei, Yan; Liu, Feng; Zhou, Chenggang; Mu, Wei

    2017-07-26

    Bradysia odoriphaga is the major pest affecting Chinese chive production, and in China, it has developed widespread resistance to organophosphorus insecticides. Chlorfenapyr is a promising pyrrole insecticide with a unique mechanism of action that does not confer cross-resistance to neurotoxic insecticides. However, the effect of chlorfenapyr on organophosphate-resistant B. odoriphaga is not well understood. The present study evaluated the potential of chlorfenapyr for the control of phoxim-resistant B. odoriphaga. The results showed that chlorfenapyr had significant insecticidal activity to B. odoriphaga in multiple developmental stages, and there were no significant differences in susceptibility between the field (phoxim-resistant) and laboratory (phoxim-susceptible) populations. The pot experiment and field trials confirmed the results of our laboratory bioassays. In the field trial, chlorfenapyr applied at 3.0, 6.0, or 12.0 kg of active ingredient (a.i.)/ha significantly decreased the number of B. odoriphaga and improved the yield compared to phoxim at 6.0 kg of a.i./ha and the control conditions. Moreover, the final residues of chlorfenapyr on plants were below the maximum residue limits (MRLs) as a result of its non-systemic activity. These results demonstrate that chlorfenapyr has potential as a potent alternative to phoxim for controlling B. odoriphaga.

  3. pyrroles

    Indian Academy of Sciences (India)

    and various aldehydes to afford 4H-pyrano[3,2-b]pyrrole derivatives in moderate to good yield using ferric .... (pyran C5), 122.8, 122.4, 128.9, 132.7, 133.0, 141.6. (Ar-C), 179.0 (pyran C2). 2.2f ..... After Michael-type addition of malononitrile.

  4. Activity of bifenthrin, chlorfenapyr, fipronil, and thiamethoxam against Argentine ants (Hymenoptera: Formicidae).

    Science.gov (United States)

    Wiltz, B A; Suiter, D R; Gardner, W A

    2009-12-01

    Bifenthrin, chlorfenapyr, fipronil, and thiamethoxam were evaluated for activity against the Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae). Mobility impairment and lethal times were determined after topical treatments. Ants were immobilized most quickly by bifenthrin, followed by chlorfenapyr and thiamethoxam. After 2 h, the number of fipronil-treated ants unable to walk out of test arenas did not differ from control ants. Median lethal time (LT50) after topical treatment was lowest in the bifenthrin treatment, followed by thiamethoxam, chlorfenapyr, and then fipronil. Mortality due to horizontal exposure was evaluated at 10, 20, or 30 degrees C, with topically treated ant corpses serving as donors. There was low to moderate horizontal activity in bifenthrin and chlorfenapyr treatments, with no temperature effect in bifenthrin treatments and a positive temperature effect in chlorfenapyr treatments. Mortality in the fipronil treatments was highest and was positively correlated with temperature. Thiamethoxam treatments did not differ from controls at 10 degrees C, but mortality increased with temperature. To evaluate contact activity, either all of 20% of the ants in a cohort were exposed to insecticide-treated pine needles. In both tests, mortality was highest in fipronil and bifenthrin treatments, followed by thiamethoxam, with lowest mortality in chlorfenapyr treatments. Effectiveness as a barrier was evaluated by providing a choice between bridges treated with insecticide or water. Although bifenthrin did not provide an impenetrable barrier, it was the only treatment having fewer ants than its paired control. Mortality data suggest that lack of recruitment rather than repellency account for this result.

  5. Detection of Reduced Susceptibility to Chlorfenapyr- and Bifenthrin-Containing Products in Field Populations of the Bed Bug (Hemiptera: Cimicidae).

    Science.gov (United States)

    Ashbrook, Aaron R; Scharf, Michael E; Bennett, Gary W; Gondhalekar, Ameya D

    2017-06-01

    Insecticide resistance is a major impediment for effective control of Cimex lectularius L. Previous resistance detection studies with bed bugs have focused on certain pyrethroid, neonicotinoid, organochlorine, organophosphate, and carbamate insecticides. Within the pyrethroid class, resistance studies have mostly been limited to deltamethrin, lambda-cyhalothrin, and alpha- and beta-cyfluthrin. The goal of this study was to develop diagnostic concentration bioassays for assessing bed bug susceptibility levels to chlorfenapyr- and bifenthrin-containing products. First, glass vial and filter paper bioassay methods were compared for their utility in susceptibility monitoring. Statistical comparison of toxicity data between bioassays indicated that the vial assay was less confounded by assay susbtrate effects, required less insecticide, and was faster, especially for chlorfenapyr. Next, using vial diagnostic concentrations (LC99) for each insecticide, 10 laboratory-adapted field strains and the Harlan lab-susceptible strain were screened for susceptibility to chlorfenapyr and bifenthrin. The results of this study reveal recent bed bug susceptibility levels to certain chlorfenapyr- and bifenthrin-containing products. Reduced susceptibility was detected in three and five field strains to chlorfenapyr and bifenthrin, respectively. Detection of reduced susceptibility suggests that certain strains may be segregating toward greater chlorfenapyr and bifenthrin resistance. These results merit continuous resistance monitoring efforts to detect chlorfenapyr and bifenthrin susceptibility shifts. Additionally, to reduce insecticide selection pressures and delay resistance development, adoption of integrated bed bug control strategies that combine chemical and nonchemical methods is recommended. © The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  6. Activity of bifenthrin, chlorfenapyr, fipronil, and thiamethoxam against red imported fire ants (Hymenoptera: Formicidae).

    Science.gov (United States)

    Wiltz, B A; Suiter, D R; Gardner, W A

    2010-06-01

    Bifenthrin, chlorfenapyr, fipronil, and thiamethoxam were evaluated for activity against the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Mobility impairment and lethal times were determined after topical treatments. Both immobilization and mortality occurred most quickly with bifenthrin, followed by thiamethoxam, chlorfenapyr, and fipronil. Mortality due to horizontal exposure was evaluated at 10, 20, or 30 degrees C, with three ratios of topically treated donor ant corpses to live recipients (5, 10, or 20% donors). Bifenthrin had the greatest horizontal activity of the chemicals tested. For chlorfenapyr, the only treatments having higher mortality than controls were the highest percentage donors at either 10 or 30 degrees C. Horizontal activity of fipronil was temperature dependent only with the highest proportion of donors and was lower than that ofbifenthrin but higher than that of chlorfenapyr or thiamethoxam. Mean mortality due to thiamethoxam was similar to that with chlorfenapyr. Significant mortality occurred in all of the 20 and 30 degrees C thiamethoxam treatments, but none of the 10 degrees C treatments. Effectiveness as a barrier was evaluated by providing a choice between bridges treated with insecticide or water. Although bifenthrin did not provide an impenetrable barrier, it was the only treatment having fewer ants than its paired control bridge. Mortality data suggest that a reduction in recruitment rather than repellency account for this result.

  7. Food source provisioning and susceptibility of immature and adult Tribolium castaneum on concrete partially treated with chlorfenapyr (Phantom®)

    Science.gov (United States)

    A series of experiments were conducted in which adults, pupae, and 4-week-old larvae of Tribolium castaneum (Herbst), the red flour beetle, were exposed separately on concrete arenas partially treated (14.4 % of the total area) with the insecticide chlorfenapyr (Phantom®) at 1.1 g active ingredient/...

  8. Clinical and radiological findings in chlorfenapyr poisoning

    Directory of Open Access Journals (Sweden)

    Vemuri Rama Tharaknath

    2013-01-01

    Full Text Available This is a case report of suicidal ingestion of chlorfenapyr, presenting with neurological complications after a latent period of more than a week, and rapidly progressing to death within days of symptoms. Chlorfenapyr is a moderately hazardous pesticide according to World Health Organization toxicity classification, and kills target organism by depriving it of energy through interference with oxidative phosphorylation at mitochondrial level. A pro-pesticide, chlorfenapyr takes time to convert to its active form and either this active form or a toxic metabolite causes delayed neurological symptoms. It causes significant neurotoxicity in rat models. This case report provides for the first time from India (second worldwide, clinical and "radiological evidence" (magnetic resonance imaging showing demyelinating/oedematous changes of "chlorfenapyr neurotoxicity in humans." It also highlights the "latent period" between ingestion and onset of fatal manifestations. Earlier, similar case reports of human deaths with delayed onset neurological symptoms, due to chlorfenapyr poisoning have been reported, from Japan, Columbia, and Korea.

  9. Chlorfenapyr-induced toxic leukoencephalopathy with radiologic reversibility: A case report and literature review

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Byung Hyun; Kim, Seul Kee; Yoon, Woong; Heo, Tae Wook; Lee, Yun Young [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of); Kang, Heonung Keun [Dept. of Radiology, Chonnam National University Hwasun Hospital, Hwasun (Korea, Republic of)

    2016-04-15

    Chlorfenapyr is a widely used, moderately hazardous pesticide. Previous reports have indicated that chlorfenapyr intoxication can be fatal in humans. We reported the first non-fatal case of chlorfenapyr-induced toxic leukoencephalopathy in a 44-year-old female with resolution of extensive and abnormal signal intensities in white matter tracts throughout the brain, brain stem, and spinal cord on serial magnetic resonance imaging.

  10. Physiological selectivity and activity reduction of insecticides by rainfall to predatory wasps of Tuta absoluta.

    Science.gov (United States)

    Barros, Emerson C; Bacci, Leandro; Picanco, Marcelo C; Martins, Júlio C; Rosado, Jander F; Silva, Gerson A

    2015-01-01

    In this study, we carried out three bioassays with nine used insecticides in tomato crops to identify their efficiency against tomato leaf miner Tuta absoluta, the physiological selectivity and the activity reduction of insecticides by three rain regimes to predatory wasps Protonectarina sylveirae and Polybia scutellaris. We assessed the mortality caused by the recommended doses of abamectin, beta-cyfluthrin, cartap, chlorfenapyr, etofenprox, methamidophos, permethrin, phenthoate and spinosad to T. absoluta and wasps at the moment of application. In addition, we evaluated the wasp mortality due to the insecticides for 30 days on plants that did not receive rain and on plants that received 4 or 125 mm of rain. Spinosad, cartap, chlorfenapyr, phenthoate, abamectin and methamidophos caused mortality higher than 90% to T. absoluta, whereas the pyrethroids beta-cyfluthrin, etofenprox and permethrin caused mortality between 8.5% and 46.25%. At the moment of application, all the insecticides were highly toxic to the wasps, causing mortality higher than 80%. In the absence of rain, all the insecticides continued to cause high mortality to the wasps for 30 days after the application. The toxicity of spinosad and methamidophos on both wasp species; beta-cyfluthrin on P. sylveirae and chlorfenapyr and abamectin on P. scutellaris, decreased when the plants received 4 mm of rain. In contrast, the other insecticides only showed reduced toxicity on the wasps when the plants received 125 mm of rain.

  11. Radiation Induced Polymerization of Pyrrole

    International Nuclear Information System (INIS)

    Sarada Idris; Ratnam, C.T.; Ahmad Ashrif Abu Bakar

    2016-01-01

    We demonstrate the polymerization of pyrrole by gamma irradiation. The pyrrole films were exposed to gamma ray from cobalt 60 source at doses ranging from 0 to 150 kGy. The films were subjected to structural and morphological analyses by using FTIR, SEM and AFM techniques. Similar studies were also made on pristine pyrrole film which serve as control. Results revealed that pyrrole has been successfully polymerized through irradiation induced reactions. The SEM images depicted the formation of cauliflower shape upon gamma irradiation. The structural changes of pyrrole also evidenced by FTIR spectra. Surface topography and roughness of pyrrole before and after gamma irradiation found to show significant differences. (author)

  12. 40 CFR 180.513 - Chlorfenapyr; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ...)-1H-pyrrole-3-carbonitrile] in or on the following raw agricultural commodities: Commodity Parts per... only be undertaken when the facility is not in operation, and provided exposed food has been covered... assure safe use, the label and labeling shall conform to that registered by the U.S. Environmental...

  13. Investigation of the lethal and behavioral effects of commercial insecticides on the parasitoid wasp Copidosoma truncatellum.

    Science.gov (United States)

    Ramos, Rodrigo S; de Araújo, Vitor C R; Pereira, Renata R; Martins, Júlio C; Queiroz, Obiratanea S; Silva, Ricardo S; Picanço, Marcelo C

    2018-01-01

    Copidosoma truncatellum (Hymenoptera: Encyrtidae) is an important parasitoid wasp of the soybean looper, Chrysodeixis includens, but its effectiveness can be severely curtailed by the application of certain insecticides. Therefore, to identify insecticides that are potentially compatible with C. truncatellum, the lethal and behavioral effects of nine chemicals used to control the soybean looper were evaluated for their toxicity to the wasp. Chlorantraniliprole, chlorfenapyr, flubendiamide, and indoxacarb were the least toxic insecticides to the parasitoid, resulting in mortalities of less than 25%. In contrast, cartap, deltamethrin, and methomyl caused 100% mortality, and acephate and spinosad caused 76% and 78% mortality, respectively. At least one of the detoxifying enzymes (monooxygenase, glutathione S-transferase, and/or esterases) may be involved in the mechanisms underlying the selectivity of chlorantraniliprole, chlorfenapyr, flubendiamide, and indoxacarb for the parasitoid based on the results for the insecticide plus synergist treatment. Changes in the behavioral patterns (walking time and resting time) of the parasitoid were found with exposure to acephate, flubendiamide, indoxacarb and methomyl, but behavioral avoidance was not observed. Our results indicate that the insecticides chlorantraniliprole and chlorfenapyr are the most suitable for inclusion in integrated pest management strategies for the control of C. includens. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. Ecotoxicological study of insecticide effects on arthropods in common bean.

    Science.gov (United States)

    de Barros, Emerson Cristi; Ventura, Hudson Vaner; Gontijo, Pablo Costa; Pereira, Renata Ramos; Picanço, Marcelo Coutinho

    2015-01-01

    Arthropods are an important group of macroorganisms that work to maintain ecosystem health. Despite the agricultural benefits of chemical control against arthropod pests, insecticides can cause environmental damage. We examined the effects of one and two applications of the insecticides chlorfenapyr (0.18 liters a.i. ha-1) and methamidophos (0.45 liters a.i. ha-1), both independently and in combination, on arthropods in plots of common bean. The experiment was repeated for two growing seasons. Principal response curve, richness estimator, and Shannon-Wiener diversity index analyses were performed. The insecticides generally affected the frequency, richness, diversity, and relative abundance of the arthropods. In addition, the arthropods did not experience recovery after the insecticide applications. The results suggest that the insecticide impacts were sufficiently drastic to eliminate many taxa from the studied common bean plots. © The Author 2015. Published by Oxford University Press on behalf of the Entomological Society of America.

  15. Posttreatment Feeding Affects Mortality of Bed Bugs (Hemiptera: Cimicidae) Exposed to Insecticides.

    Science.gov (United States)

    Singh, Narinderpal; Wang, Changlu; Cooper, Richard

    2016-02-01

    Insecticide sprays and dusts are used for controlling bed bugs, Cimex lectularius L. In natural environments, bed bugs have daily access to hosts after they are exposed to insecticides. The established laboratory insecticide bioassay protocols do not provide feeding after insecticide treatments, which can result in inflated mortality compared with what would be encountered in the field. We evaluated the effect of posttreatment feeding on mortality of bed bugs treated with different insecticides. None of the insecticides tested had a significant effect on the amount of blood consumed and percent feeding. The effect of posttreatment feeding on bed bug mortality varied among different insecticides. Feeding significantly reduced mortality in bed bugs exposed to deltamethrin spray, an essential oil mixture (Bed Bug Fix) spray, and diatomaceous earth dust. Feeding increased the mean survival time for bed bugs treated with chlorfenapyr spray and a spray containing an essential oil mixture (Ecoraider), but did not affect the final mortality. First instars hatched from eggs treated with chlorfenapyr liquid spray had reduced feeding compared with nymphs hatched from nontreated eggs. Those nymphs hatched from eggs treated with chlorfenapyr liquid spray and successfully fed had reduced mortality and a higher mean survival time than those without feeding. We conclude that the availability of a bloodmeal after insecticide exposure has a significant effect on bed bug mortality. Protocols for insecticide efficacy testing should consider offering a bloodmeal to the treated bed bugs within 1 to 3 d after treatment. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Comparison of Insecticide Susceptibilities of Empoasca vitis (Hemiptera: Cicadellidae) from Three Main Tea-Growing Regions in China.

    Science.gov (United States)

    Wei, Qi; Yu, Hua-Yang; Niu, Chun-Dong; Yao, Rong; Wu, Shun-Fan; Chen, Zhuo; Gao, Cong-Fen

    2015-06-01

    Empoasca vitis (Göthe) is an important insect pest in tea-growing areas of China, and chemical control is the main tactic for the management of this pest. Due to the pressure of increasing insecticide resistance and more stringent food safety regulations, development of sound IPM strategies for E. vitis is an urgent matter. This study comparatively evaluated four field populations of E. vitis from three different tea-growing regions in China for their susceptibilities to eight insecticides using a simple leaf-dip methodology. E. vitis was found to be most sensitive to indoxacarb (LC505 mg/liter) and sophocarpidine (LC50>95 mg/liter, a botanical pesticide) regardless of populations. Population (geographical) variations were higher for indoxacarb and imidacloprid than other compounds. Judging by the 95% fiducial limits of LC50 values, all populations had similar susceptibilities to chlorfenapyr, bifenthrin, and acetamiprid or imidacloprid. Correlation analysis suggested that chlorfenapyr and indoxacarb or isoprocarb may have a high risk of cross resistance. Considering potency (LC50) and maximum residual levels, chlorfenapyr and bifenthrin are good insecticide options followed by acetamiprid and indoxacarb. These results provide valuable information to intelligently select insecticides for IPM programs that are efficacious against E. vitis while also managing insecticide resistance and maximum residual levels for tea production in China. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Control of pyrethroid-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes with chlorfenapyr in Benin

    NARCIS (Netherlands)

    N'Guessan, R.; Boko, P.; Odjo, A.; Knols, B.G.J.; Akogbeto, M.; Rowland, M.

    2009-01-01

    Objective To compare the efficacy of chlorfenapyr applied on mosquito nets and as an indoor residual spray against populations of Anopheles gambiae and Culex quinquefasciatus in an area of Benin that shows problematic levels of pyrethroid resistance. Method Eight-week trial conducted in experimental

  18. Food source and residual efficacy of chlorfenapyr on sealed and unsealed concrete

    Science.gov (United States)

    Adult Tribolium castaneum (Herbst), the red flour beetle, were exposed at 1 day, and 2, 4, and 6 weeks post-treatment on sealed and unsealed concrete arenas treated with chlorfenapyr at rates of 2.8, 6.9, 13.5, 20.6, 27.5 mg active ingredient/m2. Beetles were held either with or without flour, and a...

  19. Residue behavior and risk assessment of mixed formulation of imidacloprid and chlorfenapyr in chieh-qua under field conditions.

    Science.gov (United States)

    Huang, Jian Xiang; Liu, Cong Yun; Lu, Da Hai; Chen, Jia Jia; Deng, Yi Cai; Wang, Fu Hua

    2015-10-01

    A simple and rapid method based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for the simultaneous determination of imidacloprid and chlorfenapyr residues in chieh-qua. Field trials were designed to investigate the dissipation and terminal residue behavior of the mixed formulation of imidacloprid and chlorfenapyr in chieh-qua in Guangzhou and Nanning areas. Risk assessment was performed by calculating the risk quotient (RQ) values. The developed analytical method exhibited recoveries of 89.9-110.3% with relative standard deviations (RSDs) of 2.8-12.5% at the spiked levels of 0.01, 0.10, and 1.00 mg/kg. The limit of detection (LOD) was 0.003 mg/kg, and the limit of quantification (LOQ) was 0.01 mg/kg for both imidacloprid and chlorfenapyr. It was found that the half-lives of imidacloprid in chieh-qua under field conditions were 3.3 and 3.5 days in Guangzhou and Nanning at a dose of 180 g ai/ha, while the half-lives of chlorfenapyr were 3.3 and 2.6 days, respectively. The terminal residues of imidacloprid and chlorfenapyr were from 0.01 to 0.21 mg/kg and from 0.01 to 0.46 mg/kg, respectively. Results of dietary exposure assessment showed that the RQ values were much lower than 1, indicating that the risk of imidacloprid and chlorfenapyr applied in chieh-qua was negligible to human health under recommended dosage and good agricultural practices. The proposed study would provide guidance for safe and reasonable use of imidacloprid and chlorfenapyr in chieh-qua cultivation in China.

  20. Acute toxicities and sublethal effects of some conventional insecticides on Trichogramma chilonis (Hymenoptera: Trichogrammatidae).

    Science.gov (United States)

    Wang, De-Sen; He, Yu-Rong; Guo, Xiang-Ling; Luo, Yong-Li

    2012-08-01

    The acute toxicity of 10 conventional insecticides to adult of Trichogramma chilonis Ishii (Hymenoptera: Trichogrammatidae) was bioassayed by membrane method, and then their sublethal effects on the parasitoid were evaluated in the laboratory. Based on sublethal concentration (LC30) values at 8 h after treatment, we determined that adult T. chilonis were the most susceptible to chlorfenapyr, followed by fipronil, spinosad, avermectins, beta-cypermethrin, and cartap, with lethal concentration (LC)30 values of 0.3133, 0.3269, 1.5408, 3.2961, 6.1469, and 9.021 mg/liter, respectively. The field-recommended concentrations of chlorfluazuron, indoxacarb, Bacillus thuringiensis, and tebufenozide caused Cartap and spinosad also reduced longevity (8 and 7.9 d) and fecundity (110.77 and 117.2) of treated adults, but cartap enhanced the female percentage of F1 offspring (61.6%), resulting a statistical higher R0, r(m), and lambda of treated T. chilonis. In contrast, chlorfluazuron and tebufenozide increased longevity (16.4 and 15.4 d) and fecundity (248 and 256.9) of treated adults but slightly decreased the female percentage of F1 offspring (31.4 and 38.1%). Although chlorfenapyr showed no adverse influence on longevity and fecundity, it remarkably reduced the female percentage of F1 offspring (13.5%), leading to a lower R0, r(m), and lambda of treated T. chilonis. Indoxacarb, B. thuringiensis, and beta-cypermethrin had no obvious sublethal effects on the longevity and fecundity of treated adults. Based on these results, we consider B. thuringienesis, chlorfluazuron, indoxacarb, beta-cypermethrin, and tebufenozide safe to T. chilonis, suggesting that these insecticides are compatible with this parasitoid when being used in the field. However, fipronil, chlorfenapyr, spinosad, and avermectins were very harmful to T. chilonis. Timing of application of these insecticides was critical.

  1. Toxicity of nine insecticides on four natural enemies of Spodoptera exigua

    Science.gov (United States)

    Liu, Yongqiang; Li, Xiangying; Zhou, Chao; Liu, Feng; Mu, Wei

    2016-01-01

    Spodoptera exigua, which feeds on various crops worldwide, has natural enemies that are susceptible to the insecticides used against S. exigua. We investigate the toxicity and residue risk of 9 insecticides on the development of H. axyridis, C. sinica, S. manilae and T. remus. S. manilae and T. remus adults were sensitive to all 9 insecticides (LC50 less than 2.75 mg a.i. liter−1), while H. axyridis and C. sinica adults were less sensitive (LC50 between 6 × 10−5 mg a.i. liter−1 and 78.95 mg a.i. liter−1). Emamectin benzoate, spinosad, indoxacarb, alpha-cypermethrin, chlorfenapyr and chlorantraniliprole showed no toxicity on H. axyridis, C. sinica, S. manilae and T. remus pupae with the recommended field concentrations. The risk analysis indicated that chlorantraniliprole is harmless to larvae of four natural enemies and adult of H. axyridis, C. sinica and S. manilae. Emamectin benzoate and spinosad had higher safety to the development of H. axyridis, C. sinica, S. manilae and T. remus with the risk duration less than 4d. Indoxacarb, tebufenozide, chlorfenapyr, methomyl, alpha-cypermethrin and chlorpyrifos showed dangerously toxic and long risk duration on S. manilae and T. remus adults. PMID:27958333

  2. Toxicity of nine insecticides on four natural enemies of Spodoptera exigua.

    Science.gov (United States)

    Liu, Yongqiang; Li, Xiangying; Zhou, Chao; Liu, Feng; Mu, Wei

    2016-12-13

    Spodoptera exigua, which feeds on various crops worldwide, has natural enemies that are susceptible to the insecticides used against S. exigua. We investigate the toxicity and residue risk of 9 insecticides on the development of H. axyridis, C. sinica, S. manilae and T. remus. S. manilae and T. remus adults were sensitive to all 9 insecticides (LC 50 less than 2.75 mg a.i. liter -1 ), while H. axyridis and C. sinica adults were less sensitive (LC 50 between 6 × 10 -5  mg a.i. liter -1 and 78.95 mg a.i. liter -1 ). Emamectin benzoate, spinosad, indoxacarb, alpha-cypermethrin, chlorfenapyr and chlorantraniliprole showed no toxicity on H. axyridis, C. sinica, S. manilae and T. remus pupae with the recommended field concentrations. The risk analysis indicated that chlorantraniliprole is harmless to larvae of four natural enemies and adult of H. axyridis, C. sinica and S. manilae. Emamectin benzoate and spinosad had higher safety to the development of H. axyridis, C. sinica, S. manilae and T. remus with the risk duration less than 4d. Indoxacarb, tebufenozide, chlorfenapyr, methomyl, alpha-cypermethrin and chlorpyrifos showed dangerously toxic and long risk duration on S. manilae and T. remus adults.

  3. Effect of gamma radiation on the toxicity of milbemectin and chlorfenapyr in acaricide resistant and susceptible strains of Tetranychus urticae Koch (Acari: Tetranychidae)

    International Nuclear Information System (INIS)

    Nicastro, Roberto L.; Arthur, Valter; Machi, Andre R.; Sato, Mario E.

    2011-01-01

    The spider mite Tetranychus urticae Koch is considered one of the most important phytophagous mites, causing considerable damage in several agricultural crops. The aim of this study was to evaluate the effect of gamma radiation on the toxicity of the acaricides milbemectin and chlorfenapyr in resistant and susceptible strains of T. urticae. The R and S strains for milbemectin and chlorfenapyr were irradiated with gamma radiation at Gamma cell-220 source at doses of 5, 10, 20, 40 e 80 Gy. Five concentrations of milbemectin and chlorfenapyr were evaluated, making applications 24 hours after irradiation. Mites of the controls were sprayed with the same acaricide concentrations used for the R and S strains but they were not exposed to gamma radiation. Experiments on the effects of gamma radiation on the growth rates of mites for acaricide resistant and susceptible strains of T. urticae were also carried out. Tests with the Milbemectin S strain showed an increased susceptibility to the acaricide milbemectin, when the mites were irradiated (20 Gy), in comparison with the control (non irradiated mites). For the Milbemectin R strain, there was no significant influence of gamma irradiation on the toxicity of milbemectin to the mites of this strain. For the Chlorfenapyr S strain, the effect of gamma radiation was similar to that observed for Milbemectin S strain, with increased toxicity of chlorfenapyr to the mites of this susceptible strain. In the case of the Chlorfenapyr R strain, the mites exposed to gamma radiation showed to be more tolerant to chlorfenapyr, considering the LC 10 values. The same trend was observed for the LC 50 values, however, there was no significant difference with the control. The experiments showed that doses of 200 and 300 Gy eliminated the mite populations of acaricide resistant and susceptible strains of T. urticae, in a period of ten days. The dose of 100 Gy did not lead to total elimination of the mite populations, but reduced significantly

  4. Effect of gamma radiation on the toxicity of milbemectin and chlorfenapyr in acaricide resistant and susceptible strains of Tetranychus urticae Koch (Acari: Tetranychidae)

    Energy Technology Data Exchange (ETDEWEB)

    Nicastro, Roberto L.; Arthur, Valter; Machi, Andre R., E-mail: rnicastro@cena.usp.br, E-mail: arthur@cena.usp.br [Laboratorio de Radiobiologia e Ambiente (CENA/USP), Piracicaba, SP (Brazil); Sato, Mario E., E-mail: mesato@biologico.sp.gov.br [Laboratorio de Acarologia, Instituto Biologico, Campinas, SP (Brazil)

    2011-07-01

    The spider mite Tetranychus urticae Koch is considered one of the most important phytophagous mites, causing considerable damage in several agricultural crops. The aim of this study was to evaluate the effect of gamma radiation on the toxicity of the acaricides milbemectin and chlorfenapyr in resistant and susceptible strains of T. urticae. The R and S strains for milbemectin and chlorfenapyr were irradiated with gamma radiation at Gamma cell-220 source at doses of 5, 10, 20, 40 e 80 Gy. Five concentrations of milbemectin and chlorfenapyr were evaluated, making applications 24 hours after irradiation. Mites of the controls were sprayed with the same acaricide concentrations used for the R and S strains but they were not exposed to gamma radiation. Experiments on the effects of gamma radiation on the growth rates of mites for acaricide resistant and susceptible strains of T. urticae were also carried out. Tests with the Milbemectin S strain showed an increased susceptibility to the acaricide milbemectin, when the mites were irradiated (20 Gy), in comparison with the control (non irradiated mites). For the Milbemectin R strain, there was no significant influence of gamma irradiation on the toxicity of milbemectin to the mites of this strain. For the Chlorfenapyr S strain, the effect of gamma radiation was similar to that observed for Milbemectin S strain, with increased toxicity of chlorfenapyr to the mites of this susceptible strain. In the case of the Chlorfenapyr R strain, the mites exposed to gamma radiation showed to be more tolerant to chlorfenapyr, considering the LC{sub 10} values. The same trend was observed for the LC{sub 50} values, however, there was no significant difference with the control. The experiments showed that doses of 200 and 300 Gy eliminated the mite populations of acaricide resistant and susceptible strains of T. urticae, in a period of ten days. The dose of 100 Gy did not lead to total elimination of the mite populations, but reduced

  5. Syntheses of Calix[4]Pyrroles by Amberlyst-15 Catalyzed Cyclocondensations of Pyrrole with Selected Ketones

    Directory of Open Access Journals (Sweden)

    Tanuja Bisht

    2007-11-01

    Full Text Available A facile and efficient protocol is reported for the synthesis of calix[4]pyrrolesand N-confused calix[4]pyrroles in moderate to excellent yields by reaction of dialkyl orcycloalkyl ketones with pyrrole catalyzed by reusable AmberlystTM-15 under eco-friendlyconditions.

  6. GRINDING SOLVENT-FREE PAAL-KNORR PYRROLE SYNTHESIS ...

    African Journals Online (AJOL)

    Paal-Knorr pyrrole synthesis on smectites as recyclable and green catalysts. Bull. Chem. Soc. .... 1-Propyl-2,5-dimethyl-1H-pyrrole (8a). Oil (reported as oil .... of pyrroles catalyzed by zirconium chloride under solvent-free conditions . Ultrason.

  7. The nonadiabatic deactivation paths of pyrrole

    International Nuclear Information System (INIS)

    Barbatti, Mario; Vazdar, Mario; Aquino, Adelia J. A.; Eckert-Maksic, Mirjana; Lischka, Hans

    2006-01-01

    Multireference configuration interaction (MRCI) calculations have been performed for pyrrole with the aim of providing an explanation for the experimentally observed photochemical deactivation processes. Potential energy curves and minima on the crossing seam were determined using the analytic MRCI gradient and nonadiabatic coupling features of the COLUMBUS program system. A new deactivation mechanism based on an out-of-plane ring deformation is presented. This mechanism directly couples the charge transfer 1 ππ* and ground states. It may be responsible for more than 50% of the observed photofragments of ππ*-excited pyrrole. The ring deformation mechanism should act complementary to the previously proposed NH-stretching mechanism, thus offering a more complete interpretation of the pyrrole photodynamics

  8. Insecticide exposure affects DNA and antioxidant enzymes activity in honey bee species Apis florea and A. dorsata: Evidence from Punjab, Pakistan.

    Science.gov (United States)

    Hayat, Khizar; Afzal, Muhammad; Aqueel, Muhammad Anjum; Ali, Sajjad; Saeed, Muhammad Farhan; Khan, Qaiser M; Ashfaq, Muhammad; Damalas, Christos A

    2018-04-23

    Insecticide exposure can affect honey bees in agro-ecosystems, posing behavioral stresses that can lead to population decline. In this study, insecticide incidence, DNA damage, and antioxidant enzyme activity were studied in Apis florea and A. dorsata honey bee samples collected from insecticide-treated and insecticide-free areas of Punjab, Pakistan. Seven insecticides: chlorpyrifos, dimethoate, imidacloprid, phorate, emamectin, chlorfenapyr, and acetamiprid were detected in seven samples of A. florea and five samples of A. dorsata. In total, 12 samples (22.2%) of honey bees were found positive to insecticide presence out of 54 samples. The most frequently detected insecticide was chlorpyrifos, which was found in four samples (7.4%), with a concentration ranging from 0.01 to 0.05 μg/g and an average concentration 0.03 μg/g. The comet assay or single cell gel electrophoresis assay, a simple way to measure DNA strand breaks in eukaryotic cells, was used to microscopically find damage of DNA at the level of a single cell. Comet tail lengths of DNA in A. florea and A. dorsata samples from insecticide-treated areas were significantly higher (P honey bee samples from insecticide-treated and insecticide-free areas, while glutathione S-transferase (GST) activity showed a significant reduction in response to insecticide exposure. Significant positive correlations were detected between enzyme activity and insecticide concentration in honey bee species from insecticide-treated areas compared with control groups. Toxicity from pesticide exposure at sub-lethal levels after application or from exposure to pesticide residues should not be underestimated in honey bees, as it may induce physiological impairment that can decline honey bees' health. Copyright © 2018. Published by Elsevier B.V.

  9. Synergistic action of octopamine receptor agonists on the activity of selected novel insecticides for control of dengue vector Aedes aegypti (Diptera: Culicidae) mosquito.

    Science.gov (United States)

    Ahmed, Mohamed Ahmed Ibrahim; Vogel, Christoph Franz Adam

    2015-05-01

    Studying insecticide resistance in mosquitoes has attracted the attention of many scientists to elucidate the pathways of resistance development and to design novel strategies in order to prevent or minimize the spread and evolution of resistance. Here, we tested the synergistic action of piperonyl butoxide (PBO) and two octopamine receptor (OR) agonists, amitraz (AMZ) and chlordimeform (CDM) on selected novel insecticides to increase their lethal action on the fourth instar larvae of Aedes aegypti L. However, chlorfenapyr was the most toxic insecticide (LC50 = 193, 102, and 48 ng/ml, after 24, 48, and 72 h exposure, respectively) tested. Further, PBO synergized all insecticides and the most toxic combinatorial insecticide was nitenpyram even after 48 and 72 h exposure. In addition, OR agonists significantly synergized most of the selected insecticides especially after 48 and 72 h exposure. The results imply that the synergistic effects of amitraz are a promising approach in increasing the potency of certain insecticides in controlling the dengue vector Ae. aegypti mosquito. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Oxidative coupling and polymerization of pyrroles

    International Nuclear Information System (INIS)

    Hansen, Gregers Hendrik; Henriksen, Rikke Morck; Kamounah, Fadhil S.; Lund, Torben; Hammerich, Ole

    2005-01-01

    The electrochemical oxidation of 2,4-dimethyl-3-ethylpyrrole in acetonitrile has been studied using cyclic voltammetry, constant current coulometry, preparative electrolyses and ab initio calculations. The product analysis after the preparative electrolyses was carried out by HPLC combined with UV-vis and electrospray ionization MS detection. The aim of the work was to address some of the unresolved problems in the oxidative oligomerization and polymerization of alkylpyrroles. The title compound was chosen as a model for studies of pyrroles that are more basic than the solvent-supporting electrolyte system and for that reason are forced to serve as the base accepting the protons released during the coupling steps. The voltammograms obtained by cyclic voltammetry at a substrate concentration of 2 mM and voltage scan rates between 0.02 and 2 V s -1 showed a characteristic trace-crossing phenomenon that could be demonstrated by digital simulation to be related to that fact that the deprotonations of the initially formed dimer dication are slow with second order rate constants in the range 10 3 -10 4 M -1 s -1 . The relative stability of the different tautomers of the protonated pyrrole monomer and the corresponding 2,2'-dimer was determined by ab initio calculations at the RHF 6-31G(d) level. The studies also included investigations of the effects resulting from addition of a non-nucleophilic base, 2,6-di-tert-butylpyridine, to the voltammetry solutions. The major product observed after preparative electrolyses was a trimer the structure of which is proposed to include a central 2H-pyrrole unit. Since 2H-pyrroles are stronger bases than the corresponding 1H-pyrroles, the trimer is effectively protected against further oxidation by protonation. Two other trimers were observed as minor or trace products as well as a 1H,2H-dimer and several tetramers, also in trace amounts. In addition to the dimer, the trimers and the tetramers, a number of other minor products could be

  11. Activity of Selected Formulated Biorational and Synthetic Insecticides Against Larvae of Helicoverpa armigera (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Vivan, L M; Torres, J B; Fernandes, P L S

    2017-02-01

    This work studied 17 insecticides belonging to nucleopolyhedrovirus (NPV), Bacillus thuringiensis (Bt kurstaki and Bt aizawai), benzoylureas (insect growth regulators [IGRs]), carbamates, organophosphates, spinosyns, and diamides against larvae of Helicoverpa armigera (Hübner), invasive species in the South American continent. Larvae of different instars were fed for 7 d with untreated or insecticide-treated diets. Mortality was recorded daily for 7 d, and surviving larvae were individually weighed on the seventh day. The NPV and Bt insecticides caused 100% mortality of first-instar larvae and first-instar and second-instar larvae, respectively. However, both NPV and Bt-based products caused low mortality of third-instar larvae and did not kill older larvae. The IGR lufenuron was highly effective against all three ages of larvae tested, whereas teflubenzuron and triflumuron produced maximum 60% mortality of second-instar larvae and lower than 50% to older larvae. Thiodicarb, chlorantraniliprole, indoxacarb, chlorpyrifos, and chlorfenapyr, irrespective of tested age, caused 100% mortality of larvae, with the last two insecticides reaching 100% mortality within 2 d of feeding on the treated diet. Flubendiamide caused lower mortality but significantly affected the weight of surviving larvae, whereas neither spinosad nor methomyl produced significant mortality or affected the weight of larvae. Based on the results, the age of H. armigera larvae plays an important role in the recommendation of NPV and Bt insecticides. Furthermore, there are potential options between biological and synthetic insecticides tested against H. armigera, and recording larval size during monitoring, in addition to the infestation level, should be considered when recommending biological-based insecticides to control this pest. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  12. Flexible supercapacitor based on electrochemically synthesized pyrrole formyl pyrrole copolymer coated on carbon microfibers

    International Nuclear Information System (INIS)

    Gholami, Mehrdad; Moozarm Nia, Pooria; Narimani, Leila; Sokhakian, Mehran; Alias, Yatimah

    2016-01-01

    Highlights: • A Flexible supercapacitor prepared by carbon microfibers coated with P(Py-co-FPy). • The variation of capacitance with different mole ratio of monomers is investigated. • The capacitance measured by different electrochemical methods. • This flexible supercapacitor can be discharged in higher currents for longer time. - Abstract: The main objective of this work is to prepare a flexible supercapacitor using electrochemically synthesized pyrrole formyl pyrrole copolymer P(Py-co-FPy) coated on the carbon microfibers. Due to difficulties of working with carbon microfibers, glassy carbon was used to find out optimized conditions by varying mole ratio of pyrrole and formyl pyrrole monomers on the capacitance value. The prepared electrodes were characterized using Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FESEM), Brunauer–Emmett–Teller (BET) analysis, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Then the X-ray photoelectron spectroscopy (XPS) was used to characterize the optimized electrode. The specific capacitance is calculated using cyclic voltammetry, charge/discharge method, and impedance spectroscopy. The charge/discharge study reveals that the best specific capacitance is estimated to be 220.3 mF cm"−"2 for equal mole fraction of pyrrole and formyl pyrrole Py (0.1)-FP (0.1) at discharge current of 3 × 10"−"4 A. This optimized electrode keeps about 92% of its capacitance value in high current of discharging. The specific capacitances calculated by all the mentioned methods are in agreement with each other. Finally, the found optimized conditions were successfully applied to produce a flexible supercapacitor on the surface of carbon microfibers.

  13. Flexible supercapacitor based on electrochemically synthesized pyrrole formyl pyrrole copolymer coated on carbon microfibers

    Energy Technology Data Exchange (ETDEWEB)

    Gholami, Mehrdad, E-mail: mehrdad897@um.edu.my [University of Malaya center for ionic liquids, Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Chemistry, Marvdasht Branch, Islamic Azad University, P.O. Box 465, Marvdasht (Iran, Islamic Republic of); Moozarm Nia, Pooria, E-mail: pooriamn@yahoo.com [University of Malaya center for ionic liquids, Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Narimani, Leila, E-mail: Narimani.leila@gmail.com [University of Malaya center for ionic liquids, Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Sokhakian, Mehran, E-mail: m.sokhakian@gmail.com [University of Malaya center for ionic liquids, Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Alias, Yatimah, E-mail: yatimah70@um.edu.my [University of Malaya center for ionic liquids, Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia); Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2016-08-15

    Highlights: • A Flexible supercapacitor prepared by carbon microfibers coated with P(Py-co-FPy). • The variation of capacitance with different mole ratio of monomers is investigated. • The capacitance measured by different electrochemical methods. • This flexible supercapacitor can be discharged in higher currents for longer time. - Abstract: The main objective of this work is to prepare a flexible supercapacitor using electrochemically synthesized pyrrole formyl pyrrole copolymer P(Py-co-FPy) coated on the carbon microfibers. Due to difficulties of working with carbon microfibers, glassy carbon was used to find out optimized conditions by varying mole ratio of pyrrole and formyl pyrrole monomers on the capacitance value. The prepared electrodes were characterized using Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FESEM), Brunauer–Emmett–Teller (BET) analysis, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Then the X-ray photoelectron spectroscopy (XPS) was used to characterize the optimized electrode. The specific capacitance is calculated using cyclic voltammetry, charge/discharge method, and impedance spectroscopy. The charge/discharge study reveals that the best specific capacitance is estimated to be 220.3 mF cm{sup −2} for equal mole fraction of pyrrole and formyl pyrrole Py (0.1)-FP (0.1) at discharge current of 3 × 10{sup −4} A. This optimized electrode keeps about 92% of its capacitance value in high current of discharging. The specific capacitances calculated by all the mentioned methods are in agreement with each other. Finally, the found optimized conditions were successfully applied to produce a flexible supercapacitor on the surface of carbon microfibers.

  14. Susceptibility of field populations of the diamondback moth, Plutella xylostella, to a selection of insecticides in Central China.

    Science.gov (United States)

    Zhang, Shuzhen; Zhang, Xiaolei; Shen, Jun; Mao, Kaikai; You, Hong; Li, Jianhong

    2016-09-01

    The diamondback moth (DBM), Plutella xylostella (L.) (Lepidoptera: Plutellidae), is a globally distributed and important economic pest. Chemical control is the primary approach to regulate populations of this pest. However, resistance to insecticides evolves following heavy and frequent use. Therefore, the insecticide resistance in field populations of P. xylostella collected from Central China from 2013 to 2014 was determined with a leaf-dipping method. Based on the results of the monitoring, P. xylostella has developed high levels of resistance to beta-cypermethrin (resistance ratio=69.76-335.76-fold), Bt (WG-001) (RR=35.43-167.36), and chlorfluazuron (RR=13.60-104.95) and medium levels of resistance to chlorantraniliprole (RR=1.19-14.26), chlorfenapyr (RR=4.22-13.44), spinosad (RR=5.89-21.45), indoxacarb (RR=4.01-34.45), and abamectin (RR=23.88-95.15). By contrast, the field populations of P. xylostella remained susceptible to or developed low levels of resistance to diafenthiuron (RR=1.61-8.05), spinetoram (RR=0.88-2.35), and cyantraniliprole (RR=0.4-2.15). Moreover, the LC50 values of field populations of P. xylostella were highly positively correlated between chlorantraniliprole and cyantraniliprole (r=0.88, P=0.045), chlorantraniliprole and spinosad (r=0.66, P=0.039), spinosad and diafenthiuron (r=0.57, P=0.0060), and chlorfenapyr and diafenthiuron (r=0.51, P=0.016). Additionally, the activities of detoxification enzymes in field populations of P. xylostella were significantly positively correlated with the log LC50 values of chlorantraniliprole and spinosad. The results of this study provide an important base for developing effective and successful strategies to manage insecticide resistance in P. xylostella. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Impact of insecticides used to control Spodoptera frugiperda (J.E. Smith in corn on survival, sex ratio, and reproduction of Trichogramma pretiosum Riley offspring

    Directory of Open Access Journals (Sweden)

    Jander R Souza

    2013-06-01

    Full Text Available Corn (Zea mays L. is cultivated in large areas and considered one of the world's major cereal crops. There are several arthropod pests that can reduce its production such as the fall armyworm, Spodoptera frugiperda (J.E. Smith (Lep.: Noctuidae, which is considered to be the main pest for corn. Fall armyworm is primarily controlled by insecticides. The use of biological control agents to manage this pest is growing with an emphasis on the egg parasitoid Trichogramma pretiosum Riley (Hym.: Trichogrammatidae. Thus, the aim of this research was to evaluate the impact of the following insecticides (g ai L-1 beta-cypermethrin (0.03, chlorfenapyr (0.60, chlorpyrifos (0.96, spinosad (0.16, etofenprox (0.10, triflumuron (0.08, alfa-cypermethrin/teflubenzuron (0.0425/0.0425, and lambda-cyhalothrin/thiamethoxam (0.11/0.083 on survival, sex ratio, reproduction, and T. pretiosum offspring. Distilled water was used as a control. Commercial insecticide formulations were diluted in distilled water. Bioassays used Anagasta kuehniella eggs treated with insecticides which were afterwards exposed to parasitism. Bioassays were conducted under controlled conditions at 25 ± 2 °C, 70 ± 10% RH, and 12:12 h photoperiod. Alfa-cypermethrin/teflubenzuron, beta-cypermethrin, chlorpyrifos, chlorfenapyr, spinosad, etofenprox, and lambda-cyhalothrin/thiamethoxam reduced parasitism capacity of maternal generation females as well as the percentage of insect emergence from the F1 generation. Only triflumuron was selective for T. pretiosum and can be recommended along with this parasitoid in fall armyworm management programs in corn.

  16. Preparation of conductive membranes using poly pyrrole

    International Nuclear Information System (INIS)

    Madaeni, S.; Khavaran, B.

    2003-01-01

    Conductive membranes show many benefits including fouling reduction for feeds containing ionic species. These membranes may be prepared either by conductive polymers or coating of the surfaces of non-conductive membranes with conductive polymer. In this research, the commercial micro filtration GVHP membrane manufactured from PVDF was coated with poly pyrrole using two different techniques. The conductivity of the prepared membranes was measured. In this paper, effects of various factors including concentration of the solutions, oxidizing agents, time for leaving the support in the solutions, support type and temperature on membrane conductivity were investigated

  17. Macrophage activating activity of pyrrole alkaloids from Morus alba fruits.

    Science.gov (United States)

    Kim, Seon Beom; Chang, Bo Yoon; Jo, Yang Hee; Lee, Sang Hoon; Han, Sang-Bae; Hwang, Bang Yeon; Kim, Sung Yeon; Lee, Mi Kyeong

    2013-01-09

    The fruits of Morus alba have been traditionally used as a tonic to enhance immune responses. The macrophage activating constituents of Morus alba fruits were purified using various column chromatography techniques. The structures of isolated compounds were determined on the basis of spectroscopic data interpretation such as 1D and 2D NMR analysis. The macrophage activating activities of isolated compounds were evaluated by measuring the production of nitric oxide, TNF-α and IL-12 in RAW 264.7 cells. The phagocytic activity was also evaluated. Five pyrrole alkaloids, 5-(hydroxymethyl)-1H-pyrrole-2-carboxaldehyde (1), 2-formyl-1H-pyrrole-1-butanoic acid (2), 2-formyl-5-(hydroxymethyl)-1H-pyrrole-1-butanoic acid (3), 2-formyl-5-(methoxymethyl)-1H-pyrrole-1-butanoic acid (4) and Morrole A (5) were isolated from the fruits of Morus alba. Morrole A (5) is first reported in nature and other pyrrole alkaloids (1-4) are first reported from Morus species. Among the isolated compounds, compounds 3 and 4 significantly activated macrophage activity by the enhancement of nitric oxide, TNF-α and IL-12 production, and the stimulation of phagocytic activity in RAW 264.7 cells. Pyrrole alkaloids, including a new compound, were isolated from Morus alba fruits. These compounds activated macrophage activity in RAW 264.7 cells. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  18. Adsorption characteristics and polymerization of pyrrole on Y-zeolites

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Akihiko; Kitajima, Tsutomu; Tsutsumi, Kazuo

    1999-10-26

    Conductive polymers have attracted considerable interest from the viewpoint of their electrochemical aspects and have been investigated for application in novel devices such as solid electrolyte cells and molecular electronic devices. Adsorption characteristics and polymerization of pyrrole on Y-zeolites of different cation types (NaY, HY, and CuY) have been investigated in connection with adsorption behavior, in situ IR spectroscopy, and EPR spectroscopy. Adsorption of pyrrole on NaY is physisorption giving no significant changes in IR and EPR spectra. In the adsorption on HY and CuY, the formation of pyrrole oligomers or polymers is observed. Pyrrole oligomer formed on HY is a nonconjugated one, which gives no EPR signal. In the case of CuY, EPR signal assigned to polaron of polypyrrole was observed at g = 2.008 by the pyrrole adsorption. The relationship between the amount of the spin of g = 2.008 and the adsorbed amount of pyrrole was linear even at the number of pyrrole exceeding that of Cu{sub 2+}, which suggests that the polymerization giving conjugated polypyrrole would take place on Cu{sup 2+} sites and the polypyrrole of aromatic form would be oxidized to quinoid form to give polaron on CuY surface.

  19. Hydrolytic study of the copolymer Poly pyrrole/ Polyethyleneglycol and Poly pyrrole synthesized by plasma

    International Nuclear Information System (INIS)

    Colin, E.; Enriquez, M.A.; Olayo, M.G.; Cruz, G.J.; Carapia, L.; Romero, M.; Morales, J.; Olayo, R.

    2006-01-01

    In this work the study about the hydrolytic compatibility of semiconductor polymers, copolymer Poly pyrrole/ Polyethyleneglycol (PPy/PEG) and Poly pyrrole (PPy) for their possible use as biomaterials. The polymers were synthesized by plasma between 10 and 100 W, with discharges of splendor RF to 13.5 MHz with resistive coupling. The hydrolytic affinity was evaluated calculating the contact angle with solutions of NaCl, NaCl-MgSO 4 and Krebs-Ringer. The results show a hydrophilicity increment due to the increase of the surface ruggedness with the synthesis energy. On the contrary, the crystallinity diminishes when increasing the power in PPy and it stays approximately constant in PPy/PEG. The electric conductivity presents a growth from 2 to 4 magnitude orders in function of the water content in the polymers. (Author)

  20. Pyrrole-Pyridine and Pyrrole-Naphthyridine Hosts for Anion Recognition

    Directory of Open Access Journals (Sweden)

    M. Angeles García

    2015-05-01

    Full Text Available The association constants of the complexes formed by two hosts containing pyrrole, amide and azine (pyridine and 1,8-naphthyridine groups and six guests, all monoanions (Cl−, CH3CO2−, NO3−, H2PO4−, BF4−, PF6−, have been determined using NMR titrations. The X-ray crystal structure of the host N2,N5-bis(6-methylpyridin-2-yl-3,4-diphenyl-1H-pyrrole- 2,5-dicarboxamide (1 has been solved (P21/c monoclinic space group. B3LYP/6-31G(d,p and calculations were carried out in an attempt to rationalize the trends observed in the experimental association constants.

  1. Pyrrole alkaloids from the fruits of Morus alba.

    Science.gov (United States)

    Kim, Seon Beom; Chang, Bo Yoon; Hwang, Bang Yeon; Kim, Sung Yeon; Lee, Mi Kyeong

    2014-12-15

    Phytochemical investigation of the fruits of Morus alba afforded seventeen pyrrole alkaloids including five new compounds. The structures of five new pyrrole alkaloids, named morroles B-F (4, 5, 7, 16 and 17), were determined on the basis of spectroscopic interpretations. 4-[Formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl]butanoate (2) was synthesized by chemical reaction but first isolated from nature. Among isolated compounds, compounds 6 and 14 significantly inhibited pancreatic lipase activity. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Insecticide solvents: interference with insecticidal action.

    Science.gov (United States)

    Brattsten, L B; Wilkinson, C F

    1977-06-10

    Several commercial solvent mixtures commonly used as insecticide carriers in spray formulations increase by more than threefold the microsomal N-demethylation of p-chloro N-methylaniline in midgut preparations of southern army-worm (Spodoptera eridania) larvae exposed orally to the test solvents. Under laboratory conditions, the same solvent mixtures exhibit a protective action against the in vivo toxicity of the insecticide carbaryl to the larvae. The data are discussed with respect to possible solvent-insecticide interactions occurring under field conditions and, more broadly, to potential toxicological hazards of these solvents to humans.

  3. Hydroquinone–pyrrole dyads with varied linkers

    Directory of Open Access Journals (Sweden)

    Hao Huang

    2016-01-01

    Full Text Available A series of pyrroles functionalized in the 3-position with p-dimethoxybenzene via various linkers (CH2, CH2CH2, CH=CH, C≡C has been synthesized. Their electronic properties have been deduced from 1H NMR, 13C NMR, and UV–vis spectra to detect possible interactions between the two aromatic subunits. The extent of conjugation between the subunits is largely controlled by the nature of the linker, with the largest conjugation found with the trans-ethene linker and the weakest with the aliphatic linkers. DFT calculations revealed substantial changes in the HOMO–LUMO gap that correlated with the extent of conjugation found experimentally. The results of this work are expected to open up for use of the investigated compounds as components of redox-active materials in sustainable, organic electrical energy storage devices.

  4. Computational study on the functionalization of BNNC with pyrrole molecule

    Science.gov (United States)

    Payvand, Akram; Tavangar, Zahra

    2018-05-01

    The functionalization of the boron nitride nanocone (BNNC) by pyrrole molecule was studied using B3LYP/6-311+G(d) level of theory. The reaction was studied in three methods in different layers of the nanocone: Diels-Alder cycloaddition, quartet cycloaddition and the reaction of the nitrogen atom of the pyrrole molecule with the boron or nitrogen atom of the BNNC. Thermodynamic quantities, Chemical hardness and potential and electrophilicity index of the functionalized BNNC were studied. The results show that the tip of nanocone has a higher tendency for participation in the reaction and the most favorable product of the reaction between BNNC and pyrrole molecule is produced from the reaction of N atom of pyrrole with the B atom of BNNC. The reaction decreases the energy gap value which leads to increasing the reactivity and conductivity of functionalized nanocone. The calculated NICS values confirm the aromaticity in the pristine nanocone as well as in the functionalized nanocone.

  5. STUDY OF ELECTROPOLIMERIZATION PROCESSES OF PYRROLE BY CYCLIC VOLTAMMETRIC TECHNIQUE

    Directory of Open Access Journals (Sweden)

    Adhitasari Suratman

    2010-06-01

    Full Text Available Electropolymerization processes and electrochemical properties of polypyrrole as electroactive polymer have been studied by cyclic voltammetric technique. Pyrrole was electropolymerized to form polypyrrole in water-based solvent containing sodium perchlorate as supporting electrolyte in several pH values. The pH of the solutions were varied by using Britton Robinson buffer. The results showed that oxidation potential limit of electropolymerization processes of pyrrole was 1220 mV vs Ag/AgCl reference electrode. It can be seen that cyclic voltammetric respon of polypyrrole membrane that was prepared by electropolymerization processes of pyrrole at the scanning rate of 100 mV/s was stable. While the processes of pyrrole electropolymerization carried out at the variation of pH showed that the best condition was at the pH range of 2 - 6.   Keywords: polypyrolle, electropolymer, voltammetric technique

  6. Simple two-step synthesis of 2,4-disubstituted pyrroles and 3,5-disubstituted pyrrole-2-carbonitriles from enones

    Directory of Open Access Journals (Sweden)

    Murat Kucukdisli

    2014-02-01

    Full Text Available The cyclocondensation of enones with aminoacetonitrile furnishes 3,4-dihydro-2H-pyrrole-2-carbonitriles which can be readily converted to 2,4-disubstituted pyrroles by microwave-induced dehydrocyanation. Alternatively, oxidation of the intermediates produces 3,5-disubstituted pyrrole-2-carbonitriles.

  7. Synthesis, autoxidation and photooxidation of hindered pyrrole derivatives. Hindered pyrrolic nitroxide radicals; Synthese, autoxydation et photoxidation de pyrroles encombres radicaux nitroxydes pyrroliques encombres

    Energy Technology Data Exchange (ETDEWEB)

    Ramasseul, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    2,5-di-t-butyl and 2,3,5-tri-t-butyl pyrrole are prepared from pinacoline and their structure is confirmed by comparison with 2,5-di-t-butyl furan and thiophene (I.R., U.V. and N.M.R. {sup 13}C satellites observation giving J{sub 13{sub C-H}} and J{sub H{sub 3}-H{sub 4}}). The sensitized photooxidation of these hindered pyrroles gives corresponding hydroperoxides which most likely structure is determined using physical and chemical methods. Oxidation of 2,5-di-t-butyl and 2,3,5-tri-t-butyl pyrrole by hydrogen peroxide in presence of inorganic per-acid of by p-nitro-perbenzoic acid does not give the pyrrolic nitroxides in contrast with secondary amines. Some N-hydroxypyrroles are then prepared from pinacoline and ethyl pivaloyl-acetate. Their oxidation by lead dioxide gives the corresponding pyrrolic nitroxides. 2,5-di-t-butyl 3,4-di-ethoxycarbonyl pyrryl 1-oxy is isolated and studied spectroscopically (visible and U.V., E.P.R.). In marked contrast with ordinary nitroxides it does not show solvent effect. It can be compared with 2,4-di-t-butyl cyclopentadienone, a carbon analog. For both, the long wave length transition does not show the usual n - {pi}* behaviour; that is confirmed by E.P.R. Using Huckel method for pyrrolic nitroxide skeleton, it is possible to have a good interpretation of experimental data. (author) [French] Les di-t-butyl 2,5 et tri-t-butyl-2,3,5 pyrrole sont synthetises a partir de la pinacoline et leur structure confirmee par comparaison avec les di-t-butyl-2,5 furanne et thiophene (I.R., U.V. et R.M.N.: observation des satellites {sup 13}C conduisant a la mesure des J{sub 13{sub C-H}} et J{sub H{sub 3}{sub -H{sub 4}}). La photoxydation sensibilisee de ces pyrroles encombres conduit aux hydroperoxydes correspondants dont la structure la plus probable est determinee par les methodes physicochimiques. L'oxydation des di-t-butyl-2,5 et tri-t-butyl-2,3,5 pyrrole par l'eau oxygenee en presence de peracide mineral ou par l'acide p

  8. Synthesis of 14C analogue of 1,2-diaryl-[2-14C]-pyrroles

    International Nuclear Information System (INIS)

    Saemian, N.; Shirvani, G.; Matloubi, H.

    2007-01-01

    Three 1,2-diaryl pyrroles selective COX-2 inhibitors, 2-(4-fluorophenyl)-5-methyl-1-(4-methylsulfonyl-phenyl)-1H pyrrole, 2-(4-fluorophenyl)-1- [4-(methylsulfonyl) phenyl]-1H-pyrrole and 4-[2-(4-fluorophenyl)-1H-pyrrol-1-yl]benzenesulfon-amide, all three labeled with 14 C in the 2-position were prepared from para-fluoro-benzaldehyde-[carbonyl- 14 C]. (author)

  9. Polycondensation of pyrrole and benzaldehyde catalyzed by Maghnite–H+

    Directory of Open Access Journals (Sweden)

    2007-07-01

    Full Text Available Rapid synthesis of poly[(pyrrole-2,5-diyl-co-(benzylidene] was achieved under microwave irradiation via the condensation of pyrrole and benzaldehyde in 1,2-dichloroethane using acid exchanged montmorillonite clay called Maghnite–H+ (Mag–H+ as an efficient catalyst. The effect of the amount of catalyst and of time on the polymerization yield and on the viscosity of the polymers was studied. Compared with conventional static interfacial polymerization, the microwave-radiation polymerization reaction proceeded rapidly and was completed within 35 s. The conjugated polymer was characterized by means of 1H-NMR, X-ray diffraction, FT-IR spectroscopy and AFM. The X-ray data showed the presence of a backbone form of the [(pyrrole-2,5-diyl-co-(benzylidene] formed.

  10. Versatile functionalization of nanoelectrodes by oligonucleotides via pyrrole electrochemistry.

    Science.gov (United States)

    Descamps, Emeline; Nguyen, Khoa; Bouchain-Gautier, Christelle; Filoramo, Arianna; Goux-Capes, Laurence; Goffman, Marcello; Bourgoin, Jean-Philippe; Mailley, Pascal; Livache, Thierry

    2010-11-15

    Surface modification at the nanometer scale is a challenge for the future of molecular electronics. In particular, the precise anchoring and electrical addressing of biological scaffolds such as complex DNA nanonetworks is of importance for generating bio-directed assemblies of nano-objects for nanocircuit purposes. Herein, we consider the individual modification of nanoelectrodes with different oligonucleotide sequences by an electrochemically driven co-polymerization process of pyrrole and modified oligonucleotide sequences bearing pyrrole monomers. We demonstrate that this one-step technique presents the advantages of simplicity, localization of surface modification, mechanical, biological and chemical stability of the coatings, and high lateral resolution.

  11. Insecticide Exposure in Parkinsonism

    National Research Council Canada - National Science Library

    Bloomquist, Jeffrey

    2002-01-01

    Behavioral, neurochemical, and immunocytochemical studies characterized the possible role of insecticide exposure in the etiology of Parkinson's disease as it may relate to Gulf War Syndrome. Chlorpyrifos (CP) and permethrin (PM...

  12. Insecticide Exposure in Parkinsonism

    National Research Council Canada - National Science Library

    Bloomquist, Jeffrey

    2001-01-01

    Behavioral, neurochemical, and immunocytochemical studies characterized the possible role of insecticide exposure in the etiology of Parkinson's disease as it may relate to Gulf War Syndrome. Chlorpyrifos (CP) and permethrin (PM...

  13. Insecticide Exposure in Parkinsonism

    National Research Council Canada - National Science Library

    Bloomquist, Jeffrey

    2003-01-01

    Behavioral, neurochemical, and immunocytochemical studies are characterizing the possible role of insecticide exposure in the etiology of Parkinson's disease as it may relate to Gulf War Syndrome. Chlorpyrifos (CP) and/or permethrin (PM...

  14. 3 Insecticide Use Practice

    African Journals Online (AJOL)

    Administrator

    500,000 metric tonnes in the 1964/1965 season. Problems ... insecticides on the open market. ... effective in the management of insect pests of cocoa. .... Effectiveness and profitability of pest ... Youth in Agriculture; Programme Policy, Strategy.

  15. Insecticides and Biological Control

    Science.gov (United States)

    Furness, G. O.

    1972-01-01

    Use of insecticides has been questioned due to their harmful effects on edible items. Biological control of insects along with other effective practices for checking spread of parasites on crops are discussed. (PS)

  16. Imidazopyridine/Pyrrole and hydroxybenzimidazole/pyrrole pairs for DNA minor groove recognition.

    Science.gov (United States)

    Renneberg, Dorte; Dervan, Peter B

    2003-05-14

    The DNA binding properties of fused heterocycles imidazo[4,5-b]pyridine (Ip) and hydroxybenzimidazole (Hz) paired with pyrrole (Py) in eight-ring hairpin polyamides are reported. The recognition profile of Ip/Py and Hz/Py pairs were compared to the five-membered ring pairs Im/Py and Hp/Py on a DNA restriction fragment at four 6-base pair recognition sites which vary at a single position 5'-TGTNTA-3', where N = G, C, T, A. The Ip/Py pair distinguishes G.C from C.G, T.A, and A.T, and the Hz/Py pair distinguishes T.A from A.T, G.C, and C.G, affording a new set of heterocycle pairs to target the four Watson-Crick base pairs in the minor groove of DNA.

  17. Influence of gamma irradiation on polymerization of pyrrole and glucose oxidase immobilization onto poly (pyrrole)/poly (vinyl alcohol) matrix

    Science.gov (United States)

    Idris, Sarada; A. Bakar, Ahmad Ashrif; Thevy Ratnam, Chantara; Kamaruddin, Nur Hasiba; Shaari, Sahbudin

    2017-04-01

    This paper describes the immobilization of glucose oxidase, GOx onto polymer matrix comprising of poly(pyrrole), PPy and poly(vinyl alcohol), PVA using gamma irradiation technique. Py/PVA-GOx film was prepared by spreading PVA:GOx, 1:1 solution onto dried pyrrole film and exposed to gamma irradiation from cobalt 60 source at doses ranging from 0 to 60 kGy. The films were subjected to structural and morphological analyses by using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM), Field emission scanning electron microscope (FESEM) and Atomic-force microscopy (AFM) techniques. Similar studies were also made on pristine pyrrole film which served as control. The SEM and FTIR spectra of Py/PVA-GOx film revealed that pyrrole has been successfully polymerized through irradiation-induced reactions. The results on the morphological properties of the samples characterize using FESEM, SEM and AFM further confirmed the occurrence of radiation-induced modification of Py/PVA-GOx film. The FTIR spectra showed the existence of intermolecular interaction between polymer matrix and GOx indicating that GOx had been successfully immobilized onto Ppy/PVA matrix by radiation-induced reactions. Results revealed that radiation induced reactions such as polymerization of pyrrole, crosslinking of PVA, grafting between the adjacent PVA and pyrrole molecules as well as immobilization of GOx onto Ppy/PVA matrix occurred simultaneously upon gamma irradiation. The optimum dose for GOx immobilization in the polymer matrix found to be 40 kGy. Therefore it is clear that this irradiation technique offered a simple single process to produce Py/PVA-GOx film without additional crosslinking and polymerization agents.

  18. A colorimetric tetrathiafulvalene-calix 4 pyrrole anion sensor

    DEFF Research Database (Denmark)

    Nielsen, K. A.

    2012-01-01

    The interaction and colorimetric sensing properties of a tetrathiafulvalene substituted calix[4]pyrrole sensor with anions were investigated using H-1 NMR and absorption spectroscopic techniques. Visual color changes were observed upon addition of different anions (Cl-, Br-, CN-, and Ac......O-) to a solution of the sensor. (C) 2012 Elsevier Ltd. All rights reserved....

  19. Interesting reactivity of diketones with pyrrole under acidic condition

    Indian Academy of Sciences (India)

    e-mail: pkpsc@uohyd.ernet.in; pradeepta.panda@gmail.com. MS received 18 October 2010; revised 7 June 2011; accepted 13 June 2011. Abstract. The acid catalysed condensation of diketones with pyrrole did not result in the formation of expected divergent bisdipyrromethane always; instead the product depends on the ...

  20. Insecticide Rotation Programs with Entomopathogenic Organisms for Suppression of Western Flower Thrips (Thysanoptera: Thripidae) Adult Populations under Greenhouse Conditions.

    Science.gov (United States)

    Kivett, Jessica M; Cloyd, Raymond A; Bello, Nora M

    2015-08-01

    Western flower thrips, Frankliniella occidentalis (Pergande), is one of the most destructive insect pests of greenhouse production systems with the ability to develop resistance to a wide variety of insecticides. A common resistance management strategy is rotating insecticides with different modes of action. By incorporating entomopathogenic organisms (fungi and bacteria), which have discrete modes of action compared to standard insecticides, greenhouse producers may preserve the effectiveness of insecticides used for suppression of western flower thrips populations. The objective of this study was to determine how different rotation programs that include entomopathogenic organisms (Beauveria bassiana, Isaria fumosoroseus, Metarhizium anisopliae, and Chromobacterium subtsugae) and commonly used standard insecticides (spinosad, chlorfenapyr, abamectin, and pyridalyl) may impact the population dynamics of western flower thrips adult populations by means of suppression. Eight-week rotation programs were applied to chrysanthemum, Dendranthema x morifolium plants and weekly counts of western flower thrips adults captured on yellow sticky cards were recorded as a means to evaluate the impact of the rotation programs. A final quality assessment of damage caused by western flower thrips feeding on foliage and flowers was also recorded. Furthermore, a cost comparison of each rotation program was conducted. Overall, insecticide rotation programs that incorporated entomopathogenic organisms were not significantly different than the standard insecticide rotation programs without entomopathogenic organisms in suppressing western flower thrips adult populations. However, there were no significant differences among any of the rotation programs compared to the water control. Moreover, there was no differential effect of the rotation programs on foliage and flower quality. Cost savings of up to 34% (in US dollars) are possible when including entomopathogenic organisms in the

  1. Influence of gamma irradiation on polymerization of pyrrole and glucose oxidase immobilization onto poly (pyrrole)/poly (vinyl alcohol) matrix

    Energy Technology Data Exchange (ETDEWEB)

    Idris, Sarada, E-mail: sarada@nuclearmalaysia.gov.my [Department of Radiation Technology, Malaysian Nuclear Agency, 43000, Bangi, Selangor (Malaysia); Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering & Built Environment, Universiti Kebangsaan Malaysia, Bangi, 43600 (Malaysia); Bakar, Ahmad Ashrif A., E-mail: ashrif@ukm.edu.my [Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering & Built Environment, Universiti Kebangsaan Malaysia, Bangi, 43600 (Malaysia); Thevy Ratnam, Chantara [Department of Radiation Technology, Malaysian Nuclear Agency, 43000, Bangi, Selangor (Malaysia); Kamaruddin, Nur Hasiba [Department of Electrical, Electronic and Systems Engineering, Faculty of Engineering & Built Environment, Universiti Kebangsaan Malaysia, Bangi, 43600 (Malaysia); Shaari, Sahbudin [Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi, 43600 (Malaysia)

    2017-04-01

    Graphical abstract: The illustration of pyrrole polymerization, PVA crosslinking and immobilization of GOx onto polymer matrix. - Highlights: • Immobilization of glucose oxidase onto polymer matrices by gamma irradiation is proposed. • Crosslinking and grafting of polymers implies the immobilization reaction. • The mechanisms relies on gamma irradiation doses. • A simple single step process of polymerization, cross linking and immobilization by mean of gamma irradiation as was shown in Graphical abstract. - Abstract: This paper describes the immobilization of glucose oxidase, GOx onto polymer matrix comprising of poly(pyrrole), PPy and poly(vinyl alcohol), PVA using gamma irradiation technique. Py/PVA-GOx film was prepared by spreading PVA:GOx, 1:1 solution onto dried pyrrole film and exposed to gamma irradiation from cobalt 60 source at doses ranging from 0 to 60 kGy. The films were subjected to structural and morphological analyses by using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM), Field emission scanning electron microscope (FESEM) and Atomic-force microscopy (AFM) techniques. Similar studies were also made on pristine pyrrole film which served as control. The SEM and FTIR spectra of Py/PVA-GOx film revealed that pyrrole has been successfully polymerized through irradiation-induced reactions. The results on the morphological properties of the samples characterize using FESEM, SEM and AFM further confirmed the occurrence of radiation-induced modification of Py/PVA-GOx film. The FTIR spectra showed the existence of intermolecular interaction between polymer matrix and GOx indicating that GOx had been successfully immobilized onto Ppy/PVA matrix by radiation-induced reactions. Results revealed that radiation induced reactions such as polymerization of pyrrole, crosslinking of PVA, grafting between the adjacent PVA and pyrrole molecules as well as immobilization of GOx onto Ppy

  2. Influence of gamma irradiation on polymerization of pyrrole and glucose oxidase immobilization onto poly (pyrrole)/poly (vinyl alcohol) matrix

    International Nuclear Information System (INIS)

    Idris, Sarada; Bakar, Ahmad Ashrif A.; Thevy Ratnam, Chantara; Kamaruddin, Nur Hasiba; Shaari, Sahbudin

    2017-01-01

    Graphical abstract: The illustration of pyrrole polymerization, PVA crosslinking and immobilization of GOx onto polymer matrix. - Highlights: • Immobilization of glucose oxidase onto polymer matrices by gamma irradiation is proposed. • Crosslinking and grafting of polymers implies the immobilization reaction. • The mechanisms relies on gamma irradiation doses. • A simple single step process of polymerization, cross linking and immobilization by mean of gamma irradiation as was shown in Graphical abstract. - Abstract: This paper describes the immobilization of glucose oxidase, GOx onto polymer matrix comprising of poly(pyrrole), PPy and poly(vinyl alcohol), PVA using gamma irradiation technique. Py/PVA-GOx film was prepared by spreading PVA:GOx, 1:1 solution onto dried pyrrole film and exposed to gamma irradiation from cobalt 60 source at doses ranging from 0 to 60 kGy. The films were subjected to structural and morphological analyses by using Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), Scanning electron microscope (SEM), Field emission scanning electron microscope (FESEM) and Atomic-force microscopy (AFM) techniques. Similar studies were also made on pristine pyrrole film which served as control. The SEM and FTIR spectra of Py/PVA-GOx film revealed that pyrrole has been successfully polymerized through irradiation-induced reactions. The results on the morphological properties of the samples characterize using FESEM, SEM and AFM further confirmed the occurrence of radiation-induced modification of Py/PVA-GOx film. The FTIR spectra showed the existence of intermolecular interaction between polymer matrix and GOx indicating that GOx had been successfully immobilized onto Ppy/PVA matrix by radiation-induced reactions. Results revealed that radiation induced reactions such as polymerization of pyrrole, crosslinking of PVA, grafting between the adjacent PVA and pyrrole molecules as well as immobilization of GOx onto Ppy

  3. Botanical Insecticides in Plant Protection

    OpenAIRE

    Grdiša, Martina; Gršić, Kristina

    2013-01-01

    Botanical insecticides are natural compounds with insecticidal properties and their use in crop protection is as old as agricultural practice. Although they have been in use for over one hundred years, the advent of synthetic insecticides has unfortunately displaced their use today. Due to fast action, low cost, easy application and efficiency against a wide range of harmful species, synthetic insecticides have become an important part of pest management in modern agricultural systems....

  4. Numerical Analysis Of Hooke Jeeves-Runge Kutta To Determine Reaction Rate Equation In Pyrrole Polymerization

    International Nuclear Information System (INIS)

    Gunawan, Indra; Sulistyo, Harry; Rochmad

    2001-01-01

    The numerical analysis of Hooke Jeeves Methods combined with Runge Kutta Methods is used to determine the exact model of reaction rate equation of pyrrole polymerization. Chemical polymerization of pyrrole was conducted with FeCI 3 / pyrrole solution at concentration ratio of 1.62 mole / mole and 2.18 mole / mole with varrying temperature of 28, 40, 50, and 60 o C. FeCl 3 acts as an oxidation agent to form pyrrole cation that will polymerize. The numerical analysis was done to examine the exact model of reaction rate equation which is derived from reaction equation of initiation, propagation, and termination. From its numerical analysis, it is found that the pyrrole polymerization follows third order of pyrrole cation concentration

  5. Oxoanion Recognition by Benzene-based Tripodal Pyrrolic Receptors

    Energy Technology Data Exchange (ETDEWEB)

    Bill, Nathan [University of Texas at Austin; Kim, Dae-Sik [University of Texas at Austin; Kim, Sung Kuk [University of Texas at Austin; Park, Jung Su [University of Texas at Austin; Lynch, Vincent M. [University of Texas at Austin; Young, Neil J [ORNL; Hay, Benjamin [ORNL; Yang, Youjun [University of Texas at Austin; Anslyn, Eric [University of Texas at Austin; Sessler, Jonathan L. [University of Texas

    2012-01-01

    Two new tripodal receptors based on pyrrole- and dipyrromethane-functionalised derivatives of a sterically geared precursor, 1,3,5-tris(aminomethyl)-2,4,6-triethylbenzene, are reported; these systems, compounds 1 and 2, display high affinity and selectivity for tetrahedral anionic guests, in particular dihydrogen phosphate, pyrophosphate and hydrogen sulphate, in acetonitrile as inferred from isothermal titration calorimetry measurements. Support for the anion-binding ability of these systems comes from theoretical calculations and a single-crystal X-ray diffraction structure of the 2:2 (host:guest) dihydrogen phosphate complex is obtained in the case of the pyrrole-based receptor system, 1. Keywords anion receptors, dihydrogen phosphate, hydrogen sulphate, X-ray structure, theoretical calculations.

  6. Studies of pyrrole black electrodes as possible battery positive electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Mengoli, G.; Musiani, M.M.; Fleischmann, M.; Pletcher, D.

    1984-05-01

    It is shown that a polypyrrole, pyrrole black, may be formed anodically in several aqueous acids. The polypyrrole film shows a redox couple at less positive potentials than that required to form the film and the charge associated with these reduction and oxidation processes together with their stabilty to cycling varies with the anion in solution and the potential where the polypyrrole is formed; over-oxidation of the film caused by taking its potential too positive has a particularly disadvantageous affect. In the acids HBr and HI, the polypyrrole films can act as a storage medium for Br/sub 2/ or I/sub 2/ so that they may be used as a substrate for a X/sub 2//X/sup -/ electrode. Such electrodes may be charge/discharge cycled and the pyrrole/Br/sub 2/ electrode shows promise as a battery positive electrode.

  7. Crystal structures of unsymmetrically mixed β-pyrrole substituted ...

    Indian Academy of Sciences (India)

    NiTPP(Ph)3(CN)5, 3 complex was synthesized and its solvated structure was examined by crystallography. ... sive interactions among the peripheral substituents.28,29 ... 1H NMR spectra of porphyrins were. 1047 ... Single crystals of MTPP(Ph)3Cl5 (M = 2H and Ni(II)) .... by ∼0.3–0.6ppm but β-pyrrole phenyls do not show.

  8. Asymmetrically substituted calix[4]pyrrole with chiral substituents

    Czech Academy of Sciences Publication Activity Database

    Štěpánek, P.; Šimák, Ondřej; Nováková, Z.; Wimmer, Zdeněk; Drašar, P.

    2011-01-01

    Roč. 9, č. 3 (2011), s. 682-683 ISSN 1477-0520 R&D Projects: GA MŠk 2B06024 Grant - others:NATO(XE) CBP.EAP.CLG.982972 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50380511 Keywords : porphyrin derivatives * anion-binding * aggregation * pyrrole * ketones Subject RIV: CC - Organic Chemistry Impact factor: 3.696, year: 2011

  9. Anticholinesterase insecticide retrospective.

    Science.gov (United States)

    Casida, John E; Durkin, Kathleen A

    2013-03-25

    The anticholinesterase (antiChE) organophosphorus (OP) and methylcarbamate (MC) insecticides have been used very effectively as contact and systemic plant protectants for seven decades. About 90 of these compounds are still in use - the largest number for any insecticide chemotype or mode of action. In both insects and mammals, AChE inhibition and acetylcholine accumulation leads to excitation and death. The cholinergic system of insects is located centrally (where it is protected from ionized OPs and MCs) but not at the neuromuscular junction. Structural differences between insect and mammalian AChE are also evident in their genomics, amino acid sequences and active site conformations. Species selectivity is determined in part by inhibitor and target site specificity. Pest population selection with OPs and MCs has resulted in a multitude of modified AChEs of altered inhibitor specificity some conferring insecticide resistance and others enhancing sensitivity. Much of the success of antiChE insecticides results from a suitable balance of bioactivation and detoxification by families of CYP450 oxidases, hydrolases, glutathione S-transferases and others. Known inhibitors for these enzymes block detoxification and enhance potency which is particularly important in resistant strains. The current market for OPs and MCs of 19% of worldwide insecticide sales is only half of that of 10 years ago for several reasons: there have been no major new compounds for 30 years; resistance has eroded their effectiveness; human toxicity problems are still encountered; the patents have expired reducing the incentive to update registration packages; alternative chemotypes or control methods have been developed. Despite this decline, they still play a major role in pest control and the increasing knowledge on their target sites and metabolism may make it possible to redesign the inhibitors for insensitive AChEs and to target new sites in the cholinergic system. The OPs and MCs are down

  10. Synthesis and characterisation of new Schiff base monomers containing N-(alkyl and phenyl) pyrrole moieties

    Science.gov (United States)

    Amer, Ahcene Ait; Ilikti, Hocine; Maschke, Ulrich

    2017-11-01

    This article deals with the synthesis and characterisation of seven new functional Schiff base monomers, such as: M1: 1-(3-Pyrrole-1-yl-propylimino-methyl)-naphtalen-2-ol; M2: 2-(3-Pyrrole-1-yl-phenylimino-methyl)-phenol; M3: 1-(3-Pyrrole-1-yl-phenylimino-methyl)-naphtalen-2-ol; M4: N-(pyridin-2-yl-methylene)-2-(pyrrol-1-yl)-benzenamine; M5: N-(pyridin-2-yl-methylene)-3-(pyrrol-1-yl)-propan-1-amine; M6: 2-(3-pyrrol-1-yl-propylimino-methyl)-quinolin-8-ol; M7: 2-(3-pyrrol-1-yl-phenylimino-methyl)-quinolin-8-ol. Two series of compounds emerged from this study, N-propyl pyrrole derivatives (M1, M5, M6) and N-phenyl pyrrole compounds (M2, M3, M4, M7). All monomers were elaborated by condensation reactions between appropriate amines and aldehydes, and their molecular structures were confirmed by spectroscopic analysis methods like FT-IR, 1H NMR, 13C NMR, and GC-MS.

  11. Egg Hatch Rate and Nymphal Survival of the Bed Bug (Hemiptera: Cimicidae) After Exposure to Insecticide Sprays.

    Science.gov (United States)

    Hinson, K R; Benson, E P; Zungoli, P A; Bridges, W C; Ellis, B R

    2016-12-01

    Few studies have addressed the efficacy of insecticides used against eggs and first-instar nymphs of the bed bug, Cimex lectularius L. (Hemiptera: Cimicidae). Insect eggs are often resistant to insecticides; therefore, information on which products are effective is important. We evaluated the efficacy of four commonly used insecticide sprays applied directly to bed bug eggs. We also evaluated the efficacy of these insecticides to first-instar nymphs exposed to residuals resulting from directly spraying eggs. Temprid SC (beta-cyfluthrin, imidacloprid) was the most effective insecticide at preventing egg hatch (13% hatch rate) for pyrethroid-resistant, field-strain (Jersey City) bed bugs compared with a control (water [99% hatch rate]), Bedlam (MGK-264, sumithrin [84% hatch rate]), Demand CS (lambda-cyhalothrin [91% hatch rate]), and Phantom SC (chlorfenapyr [95% hatch rate]). Demand CS and Temprid SC were most effective at preventing egg hatch (0%) for an insecticide-susceptible (Harold Harlan) strain, followed by Bedlam (28%). Phantom SC produced a hatch rate similar to the control (97% and 96%, respectively). Harold Harlan-strain nymphs showed 100% survival for the control but 0% survival for Bedlam and Phantom SC. Jersey City-strain nymphs showed 100% survival for the control, 99% survival for Bedlam, 0% survival for Demand CS, 4% survival for Phantom SC, and 38% survival for Temprid SC. Demand CS was less effective at preventing hatch (91% hatch rate) of Jersey City-strain nymphs but was the only product to kill all nymphs (0% survival). One of the least effective products for preventing Jersey City-strain egg hatch (Phantom SC, 95% hatch rate) was the second most effective at killing nymphs, leaving only six of 141 alive. These findings indicate that survival of directly sprayed eggs and residually exposed, first-instar nymphs varies by strain, life stage, and product used. © The Authors 2016. Published by Oxford University Press on behalf of Entomological

  12. A short history of insecticides

    Directory of Open Access Journals (Sweden)

    Oberemok Volodymyr Volodymyrovych

    2015-07-01

    Full Text Available This review contains a brief history of the use of insecticides. The peculiarities, main advantages, and disadvantages of some modern insecticides are described. The names of the discoverers of some of the most popular insecticide preparations on the world market, are listed. The tendencies to find new insecticides to control the quantity of phytophagous insects are discussed. Special attention is paid to the perspective of creating preparations based on nucleic acids, in particular DNA insecticides. The use of insect-specific, short single-stranded DNA fragments as DNA insecticides, is paving the way in the field of “intellectual” insecticides that “think” before they act. It is worth noting, though, that in the near future, the quantity of produced insecticides will increase due to the challenges associated with food production for a rapidly growing population. It is concluded, that an agreeable interaction of scientists and manufacturers of insecticides should lead to the selection of the most optimal solutions for insect pest control, which would be safe, affordable, and effective at the same time.

  13. Preparation of ultrathin pyrrolic conductor films as backings of radioactive sources

    International Nuclear Information System (INIS)

    Rodriguez, L.; Los Arcos, J.M.

    1993-01-01

    A procedure for electropolymerization of pyrrole has been set up in order to produce thin (> 15 μ g/cm 2 ) homogeneous (thickness variation 2 . The experimental equipment, reagent and procedure utilized is described as well as the characterization pyrrolic films produced

  14. Self-association and infrared spectres of some heterocyclic compounds based on pyrrol in solid state

    International Nuclear Information System (INIS)

    Mulloev, N.; Nurulloev, M.; Narziev, B.N.

    1993-01-01

    Present article is devoted to self-association and infrared spectres of some heterocyclic compounds based on pyrrol in solid state. The study results of self-association specified by molecular hydrogen bonds of some heterocyclic compounds based on pyrrol on spectres of infrared absorption of stretching vibrations of N-H group were considered.

  15. 2,5-Dimethyl-1-phenylsulfonyl-1H-pyrrole-3,4-dicarbaldehyde

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available In the title compound, C14H13NO4S, the mean planes of the pyrrole and phenyl rings form a dihedral angle of 88.7 (1°. The aldehyde groups are slightly twisted from the pyrrole plane. In the crystal structure, molecules are linked into a three-dimensional framework by C—H...O hydrogen bonds.

  16. Spectroscopic and theoretical studies on the aromaticity of pyrrol-2-yl-carbonyl conformers

    Science.gov (United States)

    Dubis, Alina T.; Wojtulewski, Sławomir; Filipkowski, Karol

    2013-06-01

    The aromaticity of s-cis and s-trans pyrrol-2-yl carbonyl conformers was studied by FT-IR, 1H NMR spectroscopy and DFT calculations at the B3LYP/6-311++G(d,p) level of theory. The Harmonic Oscillator Model of Aromaticity (HOMA) and Nucleus Independent Chemical Shift (NICS) indices were calculated to estimate π-electron delocalization in the pyrrole ring. The usefulness of infrared spectroscopy in the evaluation of the aromaticity of the homogeneous set of pyrroles is discussed. The influence of 2-substitution on different aspects of aromaticity and stability of the pyrrol-2-yl carbonyl conformers is also discussed. It is concluded that the substitution effect of the title pyrrole derivatives can be explained on the basis of theoretical and experimental measurements of π-electron delocalization, including IR data.

  17. Biofunctionalization of multiwalled carbon nanotubes by electropolymerized poly(pyrrole-concanavalin A) films.

    Science.gov (United States)

    Papper, Vladislav; Elouarzaki, Kamal; Gorgy, Karine; Sukharaharja, Ayrine; Cosnier, Serge; Marks, Robert S

    2014-10-13

    The synthesis and electropolymerization of a pyrrolic concanavalin A derivative (pyrrole-Con A) onto a multiwalled carbon nanotube (MWCNT) deposit is reported. Glucose oxidase was then immobilized onto the MWCNT-poly(pyrrole-Con A) coating by affinity carbohydrate interactions with the polymerized Con A protein. The resulting enzyme electrode was applied to the amperometric detection of glucose exhibiting a high sensitivity of 36 mA cm(-2) mol(-1) L and a maximum current density of 350 μA cm(-2) . © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. EFICIÊNCIA DE INSETICIDAS PARA O CONTROLE DE Plutella xylostella (LEPIDOPTERA: PLUTELLIDAE NA CULTURA DO REPOLHO (Brassica oleracea var. capitata COMPARISON OF INSECTICIDE CONTROL EFFECTIVENESS OF Plutella xylostella (LEPIDOPTERA: PLUTELLIDAE IN CABBAGE

    Directory of Open Access Journals (Sweden)

    Fábio Shigeo Takatsuka

    2007-09-01

    Full Text Available

    O presente trabalho foi conduzido em uma área sob plantio contínuo de repolho (Brassica oleracea var. capitata em Goianápolis - GO, no período de setembro a novembro de 1996, visando comparar inseticidas para o controle da traça-das-crucíferas (Plutella xylostella. O delineamento experimental foi em blocos ao acaso com oito tratamentos e quatro repetições. Os tratamentos utilizados foram: teflubenzuron, nas doses de 25 mL, 30 mL e 40 mL de produto comercial (p.c./100 L de água; chlorfenapyr, nas doses de 30 mL, 50 mL e 100 mL de p.c./100 L de água; deltamethrin, na dose de 30 mL de p.c./100 L de água; e testemunha. Para cada tratamento realizaram-se aplicações semanais após o transplantio. As avaliações foram realizadas na colheita, contando-se o número de furos causados pela traça, em cinco cabeças comerciais de repolho, tomadas ao acaso, por parcela. Pôde-se concluir que os inseticidas teflubenzuron e chlorfenapyr foram mais eficientes que deltamethrin no controle da traça-das-crucíferas P. xylostella nas doses testadas.

    PALAVRAS-CHAVE: Inseticida; traça; controle químico.

    The research was carried out in an area under continuous cabbage cropping (Brassica oleracea var. capitata in Goianápolis, Goiás State, Brazil, from September to November 1996. The aim was to compare insecticides for diamondback moth (Plutella xylostella control. The experimental design was randomized blocks with eight treatments and four replications. The treatments were teflubenzuron in the doses of 25 mL, 30 mL and 40 mL of commercial product (c.p. / 100 L of water; chlorfenapyr in the doses of 30 mL, 50 mL and 100 mL of c.p./ 100 L of water; deltamethrin in the dose of 30 mL of c.p. / 100 L of water; and control. Treatments were applied weekly

  19. Resistance to Diamide Insecticides in Plutella xylostella (Lepidoptera: Plutellidae): Comparison Between Lab-Selected Strains and Field-Collected Populations.

    Science.gov (United States)

    Qin, Chao; Wang, Cheng-Hua; Wang, Ying-Ying; Sun, Shi-Qing; Wang, Huan-Huan; Xue, Chao-Bin

    2018-04-02

    Diamondback moth, Plutella xylostella (L.; Lepidoptera: Plutellidae), is an important pest of crucifers worldwide. The extensive use of diamide insecticides has led to P. xylostella resistance and this presents a serious threat to vegetable production. We selected chlorantraniliprole (Rf) and flubendiamide (Rh) resistance strains of P. xylostella with resistance ratios of 684.54-fold and 677.25-fold, respectively. The Rf and Rh strains underwent 46 and 36 generations of lab-selection for resistance, respectively. Low cross resistance of Rh to cyantraniliprole was found. Cross resistance to chlorfenapyr, tebufenozid, and indoxacarb was not found in Rf and Rh strains. The P. xylostella ryanodine receptor gene (PxRyR) transcripts level in the Rf and Rh strains was up-regulated. Except for Rf34 and Rh36, PxRyR expression in all generations of Rf and Rh selection gradually increased with increasing resistance. Two resistant populations were field-collected from Guangzhou Baiyun (Rb) and Zengcheng (Rz) and propagated for several generations without exposure to any pesticide had higher PxRyR expression than the susceptible strain (S). In the S strain, PxRyR expression was not related to the resistance ratio. Gene sequencing found that the RyR 4946 gene site was glycine (G) in the S, Rf, and Rh strains, and was glutamate (E) with 70% and 80% frequency in the Rb and Rz populations, respectively. The 4946 gene site was substituted by valine (V) with the frequency of 30% and 20% in Rb and Rz populations, respectively. These results increase the understanding of the mechanisms of diamide insecticide resistance in P. xylostella.

  20. A Submarine Journey: The Pyrrole-Imidazole Alkaloids

    Directory of Open Access Journals (Sweden)

    Alessandra Scolaro

    2009-11-01

    Full Text Available In his most celebrated tale “The Picture of Dorian Gray”, Oscar Wilde stated that “those who go beneath the surface do so at their peril”. This sentence could be a prophetical warning for the practitioner who voluntarily challenges himself with trying to synthesize marine sponge-deriving pyrrole-imidazole alkaloids. This now nearly triple-digit membered community has been growing exponentially in the last 20 years, both in terms of new representatives and topological complexity − from simple, achiral oroidin to the breathtaking 12-ring stylissadines A and B, each possessing 16 stereocenters. While the biosynthesis and the role in the sponge economy of most of these alkaloids still lies in the realm of speculations, significant biological activities for some of them have clearly emerged. This review will account for the progress in achieving the total synthesis of the more biologically enticing members of this class of natural products.

  1. Neurotoxicology of insecticides and pheromones

    National Research Council Canada - National Science Library

    Narahashi, Toshio

    1979-01-01

    The purpose of this symposium was to provide a forum where a variety of scientists who were interested in the interactions of insecticides and pheromones with the nervous system got together to exchange their views...

  2. A renaissance for botanical insecticides?

    Science.gov (United States)

    Isman, Murray B

    2015-12-01

    Botanical insecticides continue to be a subject of keen interest among the international research community, reflected in the steady growth in scientific publications devoted to the subject. Until very recently though, the translation of that theory to practice, i.e. the commercialisation and adoption of new botanical insecticides in the marketplace, has seriously lagged behind. Strict regulatory regimes, long the bane of small pesticide producers, are beginning to relax some of the data requirements for 'low-risk' pesticide products, facilitating movement of more botanicals into the commercial arena. In this paper I discuss some of the jurisdictions where botanicals are increasingly finding favour, some of the newer botanical insecticides in the plant and animal health arsenal and some of the specific sectors where botanicals are most likely to compete effectively with other types of insecticidal product. © 2015 Society of Chemical Industry.

  3. Grinding solvent-free Paal-Knorr pyrrole synthesis on smectites as ...

    African Journals Online (AJOL)

    Journal Home > Vol 32, No 1 (2018) > ... An environmentally benign method for the synthesis of N-substituted pyrroles from one-pot solvent-free ... conditions make this protocol practical, environmentally friendly and economically attractive.

  4. Theoretical study of structure and electronic properties of cyano-substituted pyrroles

    International Nuclear Information System (INIS)

    Rimarcik, Jan; Lukes, Vladimir; Klein, Erik; Griesser, Markus; Kelterer, Anne-Marie

    2008-01-01

    DFT and ab initio MP2 calculations of optimal geometries, dipole moments, polarizabilities, excitation energies and enthalpies of hydrogen or proton transfer from N-H group for cyano derivatives of pyrrole are presented. CN groups in α and β positions have distinct effects on electron spectra absorption bands. CN in α position causes larger bathochromic shift in comparison to β position. N-H bond dissociation enthalpies (BDE) of substituted pyrroles are higher by 7 kJ mol -1 than pyrrole BDE. Number and position of CN groups do not affect BDEs. Proton affinities of pyrrolyl anions and enthalpies of electron transfer from these anions are proportional to the number of CN groups in molecule. Each CN group causes decrease in proton affinity by 72 kJ mol -1 and 73 kJ mol -1 rise in electron transfer enthalpy. For several studied pyrroles, BDEs, proton affinities and electron transfer enthalpies in water and benzene were computed

  5. Five gene products are required for assembly of the central pyrrole moiety of coumermycin A1

    Czech Academy of Sciences Publication Activity Database

    Novotná, J.; Gust, B.; Kulik, A.; Spížek, Jaroslav; Heide, L.

    2013-01-01

    Roč. 40, č. 8 (2013), s. 915-925 ISSN 1367-5435 Institutional support: RVO:61388971 Keywords : Streptomyces * Coumermycin * Pyrrole Subject RIV: EE - Microbiology, Virology Impact factor: 2.505, year: 2013

  6. Biosynthesis, asymmetric synthesis, and pharmacology, including cellular targets, of the pyrrole-2-aminoimidazole marine alkaloids

    Digital Repository Service at National Institute of Oceanography (India)

    Al-Mourabit, A.; Zancanella, M.A.; Tilvi, S.; Romo, D.

    The pyrrole-2-aminoimidazole (P-2-AI) alkaloids are a growing family of marine alkaloids, now numbering well over 150 members, with high topographical and biological information content. Their intriguing structural complexity, rich and compact...

  7. Interaction of derived polymers from pyrrole with biocompatible solutions

    International Nuclear Information System (INIS)

    Lopez G, O. G.

    2010-01-01

    This work presents a study about the synthesis by plasma, the electric properties and superficial interaction of polymers derived from pyrrole doped with Iodine with potential use as bio material. Poly-pyrrole is a semiconductor and biocompatible polymer with potential application in the development of artificial muscles and implants where the electric interaction between cells and material is an important variable. The syntheses were made at 13.5 MHz in a glass tubular reactor of 1500 cm 3 with electrodes of 6.5 cm diameter and stainless steel flanges. An electrode was connected to the RF terminal of the power supply that is combined with a matching coupling resistance. The monomer and dopant used in this work were pyrrole and Iodine respectively, in closed containers. They were vaporized and injected separately into the reactor at room temperature and 0.1 mbar. The vapors of the reagents mixed freely in the reactor. The synthesis time was 240 min at 40, 60, 80 and 100 W. The polymers were obtained as thin films adhered to the reactor walls. The films were washed and swollen with distilled water and removed from the reactor walls with a small spatula. The polymers were irradiated with gamma rays at 18 and 22 KGy. Due to the fact that the doses are cumulative, the final dose applied was 40 KGy. The polymers characterization was carried out by Fourier Transform Infrared Spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy, contact angle, electrical conductivity and X-ray diffraction. The analyses indicates that the polymers have very similar structure in almost the entire power range, showing C-O, C=C, C-H, O-H, N-H bonds with a predominantly amorphous structure. The TGA analyses showed that the material has 4 or 5 loses of material. The first one starts after that 115 C except for the material irradiated at 40 KGy, this one begins in 87 C, the second one is in the interval of 196 and 295 C, the third one between 311 and 500 C, and the last

  8. Insecticide Resistance Reducing Effectiveness of Malaria Control

    Centers for Disease Control (CDC) Podcasts

    Malaria prevention is increasingly insecticide based. Dr. John Gimnig, an entomologist with the Division of Parasitic Diseases, CDC, discusses evidence that mosquito resistance to insecticides, which is measured in the laboratory, could compromise malaria prevention in the field.

  9. An Efficient and Short Route for the Synthesis of Reverse Pyrrole Ribonucleosides

    Directory of Open Access Journals (Sweden)

    Pereira Letícia O. R.

    2002-01-01

    Full Text Available The synthesis of reverse pyrrole ribonucleosides methyl 5-C-(4-acetyl-5-methyl-pyrrol-1-yl-2,3-O-isopropylidene-5-deoxy- beta-D-ribofuranoside (10, methyl 5-C-(4-ethoxycarbonyl-5-methyl-pyrrol-1-yl-2,3-O-isopropylidene-5-deoxy- beta-D-ribofuranoside (11, methyl 5-C-(4-acetyl-5-methyl-pyrrol-1-yl-5-deoxy-beta-D-ribofuranoside (12, methyl 5-C-(4-ethoxycarbonyl-5-methyl-pyrrol-1-yl-5-deoxy- beta-D-ribofuranoside (13, methyl 5-deoxy-5-C-(3'-formyl-4'-hydroxypropyl-pyrrol-1'-yl-2,3-O-isopropylidene- beta-D-ribofuranoside (16 and methyl 5-deoxy-5-C-(3'-formyl-pyrrol-1'-yl-2,3-O-isopropylidene- beta-D-ribofuranoside (18 are described starting from readily available methyl 5-amino-5-deoxy-2,3-O-isopropylidene-beta-D-ribofuranoside (9. The synthetic strategy for the construction of the heterocyclic ring was based on the nucleophilic attack of (9 to 4-acetyl-2-n-butoxy-5-methyl-4,5-dihydrofuran (4, 4-carbetoxy-2-n-butoxy-5-methyl-4,5-dihydrofuran (5, 4-formyl-2-n-butoxy-4,5-dihydrofuran (6 and 4-formyl-1-methyl dioxabyciclo[3.3.0]oct-3-en (8, in situ. The later compounds were obtained from reaction between 3-diazo-2,4-pentadione (1, ethyl 2-diazoacetoacetate (2 or diazomalonaldehyde (3 and enol ethers using dirhodium tetraacetate as a catalyst.

  10. Photophysical properties of fullerenes prepared in an atmosphere of pyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Glenis, S.; Cooke, S.; Chen, X.; Labes, M.M. (Temple Univ., Philadelphia, PA (United States))

    1994-10-01

    Samples of C[sub 60] and C[sub 70] containing a variety of nitrogen-doped species were prepared by arc vaporization of graphite in the presence of pyrrole. Cage-doped fractions were isolated by column chromatography and characterized by mass spectroscopy, optical absorption, and fluorescence measurements. Mass spectra were consistent with the substitution of an even number of carbon atoms of the C[sub 60] and C[sub 70] cages by nitrogen atoms. Carbonaceous clusters including fragmented fullerenes containing hydrogen atoms were also formed. UV-visible spectral analysis indicated that there is an influence of the molecular weight on the fundamental [pi]-[pi]* electronic transition. Fluorescence spectra showed a broad band containing vibrational fine structure that is attributed to photoseparated charges in the fragmented fullerenes and a shoulder on the low-energy side that is related to intrinsic excitation in the nitrogen-doped species. Fluorescence results imply a bandgap of 2.36 eV for the N doped fullerenes and the existence of intermediate excitonic transitions below the optical bandgap. Although it has not yet been possible to isolate a pure cage-doped material, the photophysical studies add credence to their existence and the importance of further attempts at their isolation. 17 refs., 4 figs., 1 tab.

  11. Characterization of poly pyrrole/montmorillonite electro polymerised onto Pt

    International Nuclear Information System (INIS)

    Castagno, K.R.L.; Azambuja, D.S.; Dalmoro, V.; Mauller, R.S.

    2010-01-01

    In this study films of polypyrrole/montmorillonite (PPy/MT) were electropolymerized on platinum in order to evaluate the performance of this technique in the preparation of nanocomposite materials and to determine the thermal properties and conductivity of the composites. The films were synthesized from a solution containing pyrrole, dodecylbenzene sulfonate, acid and two types of clays: montmorillonite-Na + (MT-Na) and montmorillonite-30B (MT-M). The characterization of the films we have used FT-IR, TEM, XRD, TGA, DSC and resistivity measurement by the four-point van der Pauw method. The study showed that the adopted method of exfoliation and the electropolymerization method used, allows obtaining nanocomposite materials. Analyses of FT-IR, TEM and XRD show that the clays are exfoliated in the polymer matrix. Thermal analysis of the films indicates that the addition of clay reflects an enhancement in the thermal properties of the matrix of PPy, but decreases the conductivity of the same. (author)

  12. The contribution of agricultural insecticide use to increasing insecticide resistance in African malaria vectors

    OpenAIRE

    Reid, Molly C.; McKenzie, F. Ellis

    2016-01-01

    The fight against malaria is increasingly threatened by failures in vector control due to growing insecticide resistance. This review examines the recent primary research that addresses the putative relationship between agricultural insecticide use and trends in insecticide resistance. To do so, descriptive evidence offered by the new research was categorized, and additional factors that impact the relationship between agricultural insecticide use and observed insecticide resistance in malari...

  13. Pyrethrum flowers and pyrethroid insecticides.

    OpenAIRE

    Casida, J E

    1980-01-01

    The natural pyrethrins from the daisy-like flower, Tanacetum or Chrysanthemum cinerariifolium, are nonpersistent insecticides of low toxicity to mammals. Synthetic analogs or pyrethroids, evolved from the natural compounds by successive isosteric modifications, are more potent and stable and are the newest important class of crop protection chemicals. They retain many of the favorable properties of the pyrethrins.

  14. Limonene--A Natural Insecticide.

    Science.gov (United States)

    Beatty, Joseph H.

    1986-01-01

    Describes a high school chemistry student's research project in which limonene was isolated from the oil of lemons and oranges. Outlines the students' tests on the use of this chemical as an insecticide. Discusses possible extensions of the exercises based on questions generated by the students. (TW)

  15. Radioligand Recognition of Insecticide Targets.

    Science.gov (United States)

    Casida, John E

    2018-04-04

    Insecticide radioligands allow the direct recognition and analysis of the targets and mechanisms of toxic action critical to effective and safe pest control. These radioligands are either the insecticides themselves or analogs that bind at the same or coupled sites. Preferred radioligands and their targets, often in both insects and mammals, are trioxabicyclooctanes for the γ-aminobutyric acid (GABA) receptor, avermectin for the glutamate receptor, imidacloprid for the nicotinic receptor, ryanodine and chlorantraniliprole for the ryanodine receptor, and rotenone or pyridaben for NADH + ubiquinone oxidoreductase. Pyrethroids and other Na + channel modulator insecticides are generally poor radioligands due to lipophilicity and high nonspecific binding. For target site validation, the structure-activity relationships competing with the radioligand in the binding assays should be the same as that for insecticidal activity or toxicity except for rapidly detoxified or proinsecticide analogs. Once the radioligand assay is validated for relevance, it will often help define target site modifications on selection of resistant pest strains, selectivity between insects and mammals, and interaction with antidotes and other chemicals at modulator sites. Binding assays also serve for receptor isolation and photoaffinity labeling to characterize the interactions involved.

  16. Knorr-Rabe partial reduction of pyrroles: Application to the synthesis of indolizidine alkaloids

    Directory of Open Access Journals (Sweden)

    Ryan John H

    2008-01-01

    Full Text Available Abstract Background The Birch reduction of electron rich pyrroles does not occur readily. However, dissolving metal reduction with zinc under acidic conditions gives 3-pyrrolines (2,5-dihydropyrroles in reasonable yield. This dissolving metal reduction was first reported by Knorr and Rabe in 1901 but since then has only been reported for the reduction of electron rich pyrroles. Results The partial reduction of bicyclic α-ketopyrrole derivatives has been performed under dissolving metal conditions with zinc and hydrochloric acid to give excellent yields of hexahydroindolizidines. This reduction method has been utilised for the diastereoselective synthesis of 5-alkylindolizidines and the stereoselectivity obtained is opposite to that of catalytic hydrogenation. Conclusion An efficient stereoselective synthesis of indolizidine alkaloids has been developed from α-ketopyrrole intermediates using a modified version of Knorr and Rabe's pyrrole reduction.

  17. Conducting polymers of decanedioic acid bis-(4-pyrrol-1-yl-phenyl) ester

    International Nuclear Information System (INIS)

    Cirpan, A.; Guner, Y.; Toppare, L.

    2004-01-01

    A dipyrrolyl monomer was synthesized via the reaction between 4-pyrrol-1-yl phenol and decanedioyl dichloride. The electrochemical behavior of this monomer was studied. Polymerization of decanedioic acid bis-(4-pyrrol-1-yl-phenyl) ester (DAPE) was achieved by chemical and constant current electrolyses methods. Copolymerization of DAPE with thiophene was performed by constant potential electrolysis in acetonitrile-tetrabutylammonium tetrafluoroborate (TBAFB), dichloromethane-TBAFB, solvent-electrolyte couples. The chemical structures and properties were investigated by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry and thermal gravimetry analysis. The conductivities of the samples were measured by a four-probe technique

  18. Conducting polymers of decanedioic acid bis-(4-pyrrol-1-yl-phenyl) ester

    Energy Technology Data Exchange (ETDEWEB)

    Cirpan, A.; Guner, Y.; Toppare, L

    2004-05-15

    A dipyrrolyl monomer was synthesized via the reaction between 4-pyrrol-1-yl phenol and decanedioyl dichloride. The electrochemical behavior of this monomer was studied. Polymerization of decanedioic acid bis-(4-pyrrol-1-yl-phenyl) ester (DAPE) was achieved by chemical and constant current electrolyses methods. Copolymerization of DAPE with thiophene was performed by constant potential electrolysis in acetonitrile-tetrabutylammonium tetrafluoroborate (TBAFB), dichloromethane-TBAFB, solvent-electrolyte couples. The chemical structures and properties were investigated by Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, differential scanning calorimetry and thermal gravimetry analysis. The conductivities of the samples were measured by a four-probe technique.

  19. Self-Aggregation in Pyrrole:  Matrix Isolation, Solid State Infrared Spectroscopy, and DFT Study

    OpenAIRE

    Gómez-Zavaglia, Andrea; Fausto, Rui

    2004-01-01

    Pyrrole (C4H5N) was embedded in low-temperature solid inert matrixes (argon, xenon; T = 9 K) and both the monomer and low-order aggregates characterized by FTIR spectroscopy. The spectroscopic studies were complemented by extensive theoretical [DFT(B3LYP)/6-311++G(d,p)] structural and vibrational studies carried out for the monomer and their self-aggregates (up to four units). The calculated spectrum for monomeric pyrrole fits well those obtained immediately after deposition (at 9 K) of dilut...

  20. Metallation of N-allenylpyrroles by superbase reagents. Synthesis of new N-substituted pyrroles

    International Nuclear Information System (INIS)

    Tarasova, O.A.; Brandsma, L.; Verkrajsse, Kh.D.; Mal'kina, A.G.; Trofimov, B.A.

    1996-01-01

    Metallation of N-allenylpyrrole by BuLi-Et 2 O (THP), BuLi-t-BuOK-THP superbases and reactions of carbanions formed with different electrophilic agents have been studied. Fundamental data on mutual influence of allene group and pyrrole ring have been obtained. Alpha-proton features the highest acidity and it is the first one to be replaced by metal. In BuLi excess (more than 3-fold) in ether or in BuLi-t-BuOK-THP system a through metallation of allene group occurs. New pyrroles functionally substituted in allene chain have been prepared. 19 refs.; 3 tabs

  1. 5-Imino-3,4-diphenyl-1H-pyrrol-2-one

    Science.gov (United States)

    Bulatov, Evgeny; Chulkova, Tatiana; Haukka, Matti

    2014-01-01

    The title compound, C16H12N2O, exists in the crystalline state as the 5-imino-3,4-di­phenyl­-1H-pyrrol-2-one tautomer. The dihedral angles between the pyrrole and phenyl rings are 35.3 (2) and 55.3 (2)°. In the crystal, inversion dimers linked by pairs of N—H⋯N hydrogen bonds generate a graph-set motif of R 2 2(8) via N—H⋯N hydrogen bonds. PMID:24764881

  2. 5-Imino-3,4-diphenyl-1H-pyrrol-2-one

    Directory of Open Access Journals (Sweden)

    Evgeny Bulatov

    2014-02-01

    Full Text Available The title compound, C16H12N2O, exists in the crystalline state as the 5-imino-3,4-diphenyl-1H-pyrrol-2-one tautomer. The dihedral angles between the pyrrole and phenyl rings are 35.3 (2 and 55.3 (2°. In the crystal, inversion dimers linked by pairs of N—H...N hydrogen bonds generate a graph-set motif of R22(8 via N—H...N hydrogen bonds.

  3. Self-Assembly of Dimeric Tetrathiafulvalene-Calix 4 pyrrole: Receptor for 1,375-Trinitrobenzene

    DEFF Research Database (Denmark)

    Nielsen, K. A.; Stein, P. C.

    2011-01-01

    The synthesis and binding properties of a tetrathiafulvalene (TTF)-calix[4]pyrrole receptor 2 appended with one 3,5-dinitrobenzoate guest moiety are reported. The preliminary studies revealed that the receptor is self-compiexing into a dimer receptor 2 center dot 2. The self-complexation of the r......The synthesis and binding properties of a tetrathiafulvalene (TTF)-calix[4]pyrrole receptor 2 appended with one 3,5-dinitrobenzoate guest moiety are reported. The preliminary studies revealed that the receptor is self-compiexing into a dimer receptor 2 center dot 2. The self...

  4. The contribution of agricultural insecticide use to increasing insecticide resistance in African malaria vectors.

    Science.gov (United States)

    Reid, Molly C; McKenzie, F Ellis

    2016-02-19

    The fight against malaria is increasingly threatened by failures in vector control due to growing insecticide resistance. This review examines the recent primary research that addresses the putative relationship between agricultural insecticide use and trends in insecticide resistance. To do so, descriptive evidence offered by the new research was categorized, and additional factors that impact the relationship between agricultural insecticide use and observed insecticide resistance in malaria vectors were identified. In 23 of the 25 relevant recent publications from across Africa, higher resistance in mosquito populations was associated with agricultural insecticide use. This association appears to be affected by crop type, farm pest management strategy and urban development.

  5. Strapped Calix[4]pyrroles Bearing an 1,3-Indanedione at a β-Pyrrolic Position: Chemodosimeters for the Cyanide Anion

    Science.gov (United States)

    Kim, Sook-Hee; Hong, Seong-Jin; Yoo, Jaeduk; Kim, Sung Kuk; Sessler, Janathan L.; Lee, Chang-Hee

    2014-01-01

    A strapped calix[4]pyrrole bearing an 1,3-indanedione group at a β-pyrrolic position has been synthesized and studied as a ratiometric cyanide selective chemosensor. A concentration-dependent bleaching of the initial yellow color was observed upon addition of the cyanide anion. The bleaching, which was observed exclusively with the cyanide anion, occurred even in the presence of other anions. Spectroscopic studies provides support for a mechanistic interpretation wherein the cyanide anion forms a complex with the receptor (K = 2.78 × 104 M-1) through a fast equilibrium, which is followed by slow nucleophilic addition to the β-position of the 1,3-indanedione group. A minimum inhibitory effect from other anions was observed, a feature that could be beneficial in the selective sensing of the cyanide anion. PMID:19639968

  6. Hydrolytic study of the copolymer Poly pyrrole/ Polyethyleneglycol and Poly pyrrole synthesized by plasma; Estudio hidrolitico del copolimero polipirrol/polietilenglicol y polipirrol sintetizado por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Colin, E.; Enriquez, M.A.; Olayo, M.G.; Cruz, G.J.; Carapia, L.; Romero, M. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Morales, J.; Olayo, R. [UAM-I, A.P. 55-534 Iztapalapa, Mexico D.F. (Mexico)

    2006-07-01

    In this work the study about the hydrolytic compatibility of semiconductor polymers, copolymer Poly pyrrole/ Polyethyleneglycol (PPy/PEG) and Poly pyrrole (PPy) for their possible use as biomaterials. The polymers were synthesized by plasma between 10 and 100 W, with discharges of splendor RF to 13.5 MHz with resistive coupling. The hydrolytic affinity was evaluated calculating the contact angle with solutions of NaCl, NaCl-MgSO{sub 4} and Krebs-Ringer. The results show a hydrophilicity increment due to the increase of the surface ruggedness with the synthesis energy. On the contrary, the crystallinity diminishes when increasing the power in PPy and it stays approximately constant in PPy/PEG. The electric conductivity presents a growth from 2 to 4 magnitude orders in function of the water content in the polymers. (Author)

  7. Effect of alkali metal ions on the pyrrole and pyridine π-electron systems in pyrrole-2-carboxylate and pyridine-2-carboxylate molecules: FT-IR, FT-Raman, NMR and theoretical studies

    Science.gov (United States)

    Świderski, G.; Wojtulewski, S.; Kalinowska, M.; Świsłocka, R.; Lewandowski, W.

    2011-05-01

    The FT-IR, FT-Raman and 1H and 13C NMR spectra of pyrrole-2-carboxylic acid (PCA) and lithium, sodium, potassium, rubidium and caesium pyrrole-2-carboxylates were recorded, assigned and compared in the Li → Na → K → Rb → Cs salt series. The effect of alkali metal ions on the electronic system of ligands was discussed. The obtained results were compared with previously reported ones for pyridine-2-carboxylic acid and alkali metal pyridine-2-carboxylates. Calculations for pyrrole-2-carboxylic acid and Li, Na, K pyrrole-2-carboxylates in B3LYP/6-311++G ** level and Møller-Plesset method in MP2/6-311++G ** level were made. Bond lengths, angles and dipole moments as well as aromaticity indices (HOMA, EN, GEO, I 6) for the optimized structures of pyrrole-2-carboxylic acid (PCA) and lithium, sodium, potassium pyrrole-2-carboxylates were also calculated. The degree of perturbation of the aromatic system of ligand under the influence of metals in the Li → Cs series was investigated with the use of statistical methods (linear correlation), calculated aromaticity indices and Mulliken, NBO and ChelpG population analysis method. Additionally, the Bader theory (AIM) was applied to setting the characteristic of the bond critical points what confirmed the influence of alkali metals on the pyrrole ring.

  8. One-pot Synthesis of Substituted Pyrroles with N,N,N',N'

    African Journals Online (AJOL)

    In this research, N,N,N'N'-tetrachlorobenzene-1,3-disulphonamide as novel catalytic reagent and N,N'-diiodo-N,N'-1,2-ethanediylbis(p-toluenesulphonamide) as new catalyst were used for the synthesis of N-substituted pyrroles in good to excellent yields under mild conditions. These reusable reagents were compared with ...

  9. Copper-promoted oxidative coupling of enamides and alkynes for the synthesis of substituted pyrroles.

    Science.gov (United States)

    Zhao, Mi-Na; Ren, Zhi-Hui; Wang, Yao-Yu; Guan, Zheng-Hui

    2014-02-10

    An efficient copper-promoted oxidative coupling of enamides with alkynes has been developed for the synthesis of substituted pyrroles. The reaction proceeded through C-H and N-H bond functionalization of enamides under mild conditions. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Synthesis and characterization of N-t-BOC protected pyrrole-sulfur oligomers and polymers

    NARCIS (Netherlands)

    Groenendaal, L.; Pieterse, K.; Vekemans, J.A.J.M.; Meijer, E.W.

    1997-01-01

    The synthesis and characterization of a new class of pyrrole-sulfur compounds is described. These compounds are designed to be precursors for an organic analogue of poly(sulfur nitride). Poly(N-t-BOC-2.5-pyrrolyl sulfide) was prepared from N-t-BOC-2,5-dibromopyrrole by first lithiating this compound

  11. A Bis-Calix[4]pyrrole Enzyme Mimic that Constrains Two Oxoanions in Close Proximity

    DEFF Research Database (Denmark)

    He, Qing; Kelliher, Michael; Bähring, Steffen

    2017-01-01

    Herein we describe a large capsule-like bis-calix[4]pyrrole 1 , that is able to host concurrently two dihydrogen phosphate anions within a relatively large internal cavity. Evidence for the concurrent, dual recognition of the encapsulated anions came from 1H NMR and UV-vis spectroscopies and ITC ...

  12. Interaction of cesium ions with calix[2]furan[4]pyrrole and its fluoride complex

    Czech Academy of Sciences Publication Activity Database

    Kříž, Jaroslav; Dybal, Jiří; Makrlík, E.; Kohnke, F. H.

    2012-01-01

    Roč. 541, 10 July (2012), s. 27-31 ISSN 0009-2614 Institutional research plan: CEZ:AV0Z40500505 Institutional support: RVO:61389013 Keywords : calix[2]furan[4]pyrrole * Cs complex * NMR Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.145, year: 2012

  13. Structure and Oxidation of Pyrrole Adducts Formed between Aflatoxin B2a and Biological Amines.

    Science.gov (United States)

    Rushing, Blake R; Selim, Mustafa I

    2017-06-19

    Aflatoxin B 2a has been shown to bind to proteins through a dialdehyde intermediate under physiological conditions. The proposed structure of this adduct has been published showing a Schiff base interaction, but adequate verification using structural elucidation instrumental techniques has not been performed. In this work, we synthesized the aflatoxin B 2a amino acid adduct under alkaline conditions, and the formation of a new product was determined using high performance liquid chromatography-time-of-flight mass spectrometry. The resulting accurate mass was used to generate a novel proposed chemical structure of the adduct in which the dialdehyde forms a pyrrole ring with primary amines rather than the previously proposed Schiff base interaction. The pyrrole structure was confirmed using 1 H, 13 C, correlation spectroscopy, heteronuclear single quantum correlation, and heteronuclear multiple bond correlation NMR and tandem mass spectrometry. Reaction kinetics show that the reaction is overall second order and that the rate increases as pH increases. Additionally, this study shows for the first time that aflatoxin B 2a dialdehyde forms adducts with phosphatidylethanolamines and does so through pyrrole ring formation, which makes it the first aflatoxin-lipid adduct to be structurally identified. Furthermore, oxidation of the pyrrole adduct produced a product that was 16 m/z heavier. When the aflatoxin B 2a -lysine (ε) adduct was oxidized, it gave a product with an accurate mass, mass fragmentation pattern, and 1 H NMR spectrum that match aflatoxin B 1 -lysine, which suggest the transformation of the pyrrole ring to a pyrrolin-2-one ring. These data give new insight into the fate and chemical properties of biological adducts formed from aflatoxin B 2a as well as possible interferences with known aflatoxin B 1 exposure biomarkers.

  14. CADDIS Volume 2. Sources, Stressors and Responses: Insecticides - Detailed Conceptual Diagram

    Science.gov (United States)

    Introduction to the insecticides module, when to list insecticides as a candidate cause, ways to measure insecticides, simple and detailed conceptual diagrams for insecticides, insecticides module references and literature reviews.

  15. CADDIS Volume 2. Sources, Stressors and Responses: Insecticides - Simple Conceptual Diagram

    Science.gov (United States)

    Introduction to the insecticides module, when to list insecticides as a candidate cause, ways to measure insecticides, simple and detailed conceptual diagrams for insecticides, insecticides module references and literature reviews.

  16. 2 Assessmen of the Efficiency of Insecticide

    African Journals Online (AJOL)

    Administrator

    malaria vectors and nuisance in West Africa – a-part. 2. Field evaluation. Malar J. 9: 341. Mosqueira B., Duchon S., Chandre F., Hougard, J. M., Carnevale P. and Mas-Coma S. (2010). Efficacy of an insecticide paint against insecticide- susceptible and resistant mosquitoes – b- Part 1: Laboratory evaluation. Malar J. 9: 340.

  17. Trifluoromethylphenyl amides as novel insecticides and fungicides

    Science.gov (United States)

    Because of increased resistance to insecticides in arthropods, it is necessary to identify new chemicals that may have novel modes of action. Following an extensive literature search for compounds with insecticidal and mosquito repellent activity, we have designed and synthesized a set of 20 trifluo...

  18. Insecticide Resistance Reducing Effectiveness of Malaria Control

    Centers for Disease Control (CDC) Podcasts

    2007-01-24

    Malaria prevention is increasingly insecticide based. Dr. John Gimnig, an entomologist with the Division of Parasitic Diseases, CDC, discusses evidence that mosquito resistance to insecticides, which is measured in the laboratory, could compromise malaria prevention in the field.  Created: 1/24/2007 by Emerging Infectious Diseases.   Date Released: 3/13/2007.

  19. Use of Graphite Oxide and Graphene Oxide as Catalysts in the Synthesis of Dipyrromethane and Calix[4]pyrrole

    Directory of Open Access Journals (Sweden)

    Sweta Mishra

    2011-08-01

    Full Text Available Graphite oxide and graphene oxides have been used as solid catalysts for the synthesis of 5,5-dialkyldipyrromethanes and calix[4]pyrroles in organic and aqueous solutions at room temperature.

  20. Efficient assembly of polysubstituted pyrroles via a (3 + 2) cycloaddition/skeletal rearrangement/redox isomerization cascade reaction.

    Science.gov (United States)

    Yu, Yuanyuan; Wang, Chunyu; He, Xinze; Yao, Xiaotong; Zu, Liansuo

    2014-07-03

    An unprecedented cascade strategy, used in conjunction with a redox isomerization, for the synthesis of 3-allyl pyrroles is reported. In a single step, readily accessible simple starting materials are transformed into highly substituted pyrroles with high efficiency. The products obtained contain allyl substituents, which can be readily elaborated to other useful functional groups. The reaction proceeds through an unusual (3 + 2) cycloaddition/skeletal rearrangement/redox isomerization pathway.

  1. of Several Organophosphorus Insecticide Metabolites

    Directory of Open Access Journals (Sweden)

    Russell L. Carr

    2015-01-01

    Full Text Available Paraoxonase (PON1 is a calcium dependent enzyme that is capable of hydrolyzing organophosphate anticholinesterases. PON1 activity is present in most mammals and previous research established that PON1 activity differs depending on the species. These studies mainly used the organophosphate substrate paraoxon, the active metabolite of the insecticide parathion. Using serum PON1 from different mammalian species, we compared the hydrolysis of paraoxon with the hydrolysis of the active metabolites (oxons of two additional organophosphorus insecticides, methyl parathion and chlorpyrifos. Paraoxon hydrolysis was greater than that of methyl paraoxon, but the level of activity between species displayed a similar pattern. Regardless of the species tested, the hydrolysis of chlorpyrifos-oxon was significantly greater than that of paraoxon or methyl paraoxon. These data indicate that chlorpyrifos-oxon is a better substrate for PON1 regardless of the species. The pattern of species differences in PON1 activity varied with the change in substrate to chlorpyrifos-oxon from paraoxon or methyl paraoxon. For example, the sex difference observed here and reported elsewhere in the literature for rat PON1 hydrolysis of paraoxon was not present when chlorpyrifos-oxon was the substrate.

  2. Insecticide resistance and intracellular proteases.

    Science.gov (United States)

    Wilkins, Richard M

    2017-12-01

    Pesticide resistance is an example of evolution in action with mechanisms of resistance arising from mutations or increased expression of intrinsic genes. Intracellular proteases have a key role in maintaining healthy cells and in responding to stressors such as pesticides. Insecticide-resistant insects have constitutively elevated intracellular protease activity compared to corresponding susceptible strains. This increase was shown for some cases originally through biochemical enzyme studies and subsequently putatively by transcriptomics and proteomics methods. Upregulation and expression of proteases have been characterised in resistant strains of some insect species, including mosquitoes. This increase in proteolysis results in more degradation products (amino acids) of intracellular proteins. These may be utilised in the resistant strain to better protect the cell from stress. There are changes in insect intracellular proteases shortly after insecticide exposure, suggesting a role in stress response. The use of protease and proteasome inhibitors or peptide mimetics as synergists with improved application techniques and through protease gene knockdown using RNA interference (possibly expressed in crop plants) may be potential pest management strategies, in situations where elevated intracellular proteases are relevant. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  3. Insecticide control of vector-borne diseases: when is insecticide resistance a problem?

    Directory of Open Access Journals (Sweden)

    Ana Rivero

    Full Text Available Many of the most dangerous human diseases are transmitted by insect vectors. After decades of repeated insecticide use, all of these vector species have demonstrated the capacity to evolve resistance to insecticides. Insecticide resistance is generally considered to undermine control of vector-transmitted diseases because it increases the number of vectors that survive the insecticide treatment. Disease control failure, however, need not follow from vector control failure. Here, we review evidence that insecticide resistance may have an impact on the quality of vectors and, specifically, on three key determinants of parasite transmission: vector longevity, competence, and behaviour. We argue that, in some instances, insecticide resistance is likely to result in a decrease in vector longevity, a decrease in infectiousness, or in a change in behaviour, all of which will reduce the vectorial capacity of the insect. If this effect is sufficiently large, the impact of insecticide resistance on disease management may not be as detrimental as previously thought. In other instances, however, insecticide resistance may have the opposite effect, increasing the insect's vectorial capacity, which may lead to a dramatic increase in the transmission of the disease and even to a higher prevalence than in the absence of insecticides. Either way-and there may be no simple generality-the consequence of the evolution of insecticide resistance for disease ecology deserves additional attention.

  4. Graphene/Poly(aniline-co-pyrrole) Nanocomposite: Potential Candidate for Supercapacitor and Microwave Absorbing Applications.

    Science.gov (United States)

    Sahoo, Sumanta; Bhattacharya, Pallab; Dhibar, Saptarshi; Hatui, Goutam; Das, Tanya; Das, Chapal Kumar

    2015-09-01

    A simple and cost-effective in-situ chemical route to prepare the nanocomposites based on graphene and Poly(aniline-co-pyrrole) [PPP] has been proposed. Introduction of graphene changes the morphology of copolymer from spherical to fiber like. Graphene/Poly(aniline-co-pyrrole) [GPPP] nanocomposite achieved highest specific capacitance of 351 F/g and energy density of 124.8 Wh/Kg at 10 mV/s scan rate. The composite also obtained moderate specific capacitance retention of 66% after 500 cycles, which establish its potentiality as supercapacitor electrode materials. The composite also exhibited high electrical conductivity and superior microwave absorbing properties (maximum reflection loss is -29.97 dB). The absorption range corresponding to ≥ 90% absorption (or -10 dB) is 2.72 GHz which is excellent for the microwave absorbing applications.

  5. Biofunctionalization of multiwalled carbon nanotubes by irradiation of electropolymerized poly(pyrrole-diazirine) films.

    Science.gov (United States)

    Papper, Vladislav; Gorgy, Karine; Elouarzaki, Kamal; Sukharaharja, Ayrine; Cosnier, Serge; Marks, Robert S

    2013-07-15

    A photoactivatable poly(pyrrole-diazirine) film was synthesized and electropolymerized as a versatile tool for covalent binding of laccase and glucose oxidase on multiwalled carbon nanotube coatings and Pt, respectively. Irradiation of the functionalized nanotubes allowed photochemical grafting of laccase and its subsequent direct electrical wiring, as illustrated by the electrocatalytic reduction of oxygen. Moreover, covalent binding of glucose oxidase as model enzyme, achieved by UV activation of electropolymerized pyrrole-diazirine, allowed a glucose biosensor to be realized. This original method to graft biomolecules combines electrochemical and photochemical techniques. The simplicity of this new method allows it to be extended easily to other biological systems. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. A C{sub 2}-symmetric ratiometric fluorescence and colorimetric anion sensor based on pyrrole derivative

    Energy Technology Data Exchange (ETDEWEB)

    Liu Ge [Department of Chemistry, Chifeng University, Chifeng 024000 (China); Shao Jie, E-mail: njshao@live.c [Department of Chemistry and Materials Science, Nanjing Forestry University, Nanjing 210037 (China)

    2011-07-15

    A C{sub 2}-symmetric fluorescence and colorimetric anion sensor (1) based on pyrrole derivative was designed and synthesized according to binding site-signaling subunit approach. The compound 1 was easily prepared by reaction of pyrrole-2,5-dicarboxaldehyde with 4-nitrophenylhydrazine in ethanol (yield=78%). In DMSO, the sensor 1 exhibited a visible color change from red to brown upon exposure to anions such as AcO{sup -} and F{sup -}; however, no obvious color changes were observed when the other tested anions (e. g. H{sub 2}PO{sub 4}{sup -}, Cl{sup -}, Br{sup -} and I{sup -}) were added. There was a significant redshift ({Delta}{lambda}{sub max}=160 nm) in UV-vis spectrum during UV-vis spectral titrations. In particular, the sensor 1 showed ratiometric fluorescence responses to anions. - Highlights: {yields} C{sub 2}-symmetric fluorescence and colorimetric anion sensor based on pyrrole derivative was designed and synthesized according to binding site-signaling subunit approach. {yields} The sensor was easily prepared by reaction of pyrrole-2,5-dicarboxaldehyde with 4-nitrophenylhydrazine in ethanol (yield=78%). {yields} In DMSO, the sensor exhibited a visible color change from red to brown upon exposure to anions such as AcO{sup -} and F{sup -}, however, no obvious color changes were observed when the other anions tested (e. g. H{sub 2}PO{sub 4}{sup -}, Cl{sup -}, Br{sup -} and I{sup -}) were added. {yields} The sensor showed ratiometric fluorescence responses to anions.

  7. Towards physical interpretation of substituent effects: the case of N- and C3-substituted pyrrole derivatives

    Czech Academy of Sciences Publication Activity Database

    Zborowski, K. K.; Szatylowicz, H.; Stasyuk, Olga A.; Krygowski, T. M.

    2017-01-01

    Roč. 28, č. 4 (2017), s. 1223-1227 ISSN 1040-0400 Institutional support: RVO:61388963 Keywords : substituent effect * pyrrole derivatives * Hammett equation * charges of the substituent active region Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.582, year: 2016 https://link.springer.com/article/10.1007%2Fs11224-017-0938-7

  8. Very Strong Binding for a Neutral Calix[4]pyrrole Receptor Displaying Positive Allosteric Binding

    DEFF Research Database (Denmark)

    Duedal, Troels; Nielsen, Kent; Olsen, Gunnar

    2017-01-01

    . The tetrathiafulvalene (TTF) subunits in the tetraTTF-calix[4]pyrrole receptor 1 present a nearly perfect shape and electronic complementarity to the NTCDA guest, which was confirmed by X-ray crystal structure analysis, DFT calculations, and electron density surface mapping. The complexation results in formation...... of a charge transfer complex (22⊆1), that is visualized as a color change from yellow to brown....

  9. Weevil x Insecticide: Does 'Personality' Matter?

    Science.gov (United States)

    Morales, Juliana A; Cardoso, Danúbia G; Della Lucia, Terezinha Maria C; Guedes, Raul Narciso C

    2013-01-01

    An insect's behavior is the expression of its integrated physiology in response to external and internal stimuli, turning insect behavior into a potential determinant of insecticide exposure. Behavioral traits may therefore influence insecticide efficacy against insects, compromising the validity of standard bioassays of insecticide activity, which are fundamentally based on lethality alone. By extension, insect 'personality' (i.e., an individual's integrated set of behavioral tendencies that is inferred from multiple empirical measures) may also be an important determinant of insecticide exposure and activity. This has yet to be considered because the behavioral studies involving insects and insecticides focus on populations rather than on individuals. Even among studies of animal 'personality', the relative contributions of individual and population variation are usually neglected. Here, we assessed behavioral traits (within the categories: activity, boldness/shyness, and exploration/avoidance) of individuals from 15 populations of the maize weevil (Sitophilus zeamais), an important stored-grain pest with serious problems of insecticide resistance, and correlated the behavioral responses with the activity of the insecticide deltamethrin. This analysis was performed at both the population and individual levels. There was significant variation in weevil 'personality' among individuals and populations, but variation among individuals within populations accounted for most of the observed variation (92.57%). This result emphasizes the importance of individual variation in behavioral and 'personality' studies. When the behavioral traits assessed were correlated with median lethal time (LT50) at the population level and with the survival time under insecticide exposure, activity traits, particularly the distance walked, significantly increased survival time. Therefore, behavioral traits are important components of insecticide efficacy, and individual variation should be

  10. Morphology and electrical properties of electrochemically synthesized pyrrole–formyl pyrrole copolymer

    Energy Technology Data Exchange (ETDEWEB)

    Gholami, Mehrdad, E-mail: mehrdad897@um.edu.my [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Marvdasht Branch, Islamic Azad University, P.O. Box 465, Marvdasht (Iran, Islamic Republic of); Nia, Pooria Moozarm, E-mail: pooriamn@yahoo.com [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Alias, Yatimah, E-mail: yatimah70@um.edu.my [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia)

    2015-12-01

    Graphical abstract: - Highlights: • The (Py–co-FPy) copolymer was synthesized electrochemically. • This copolymer has 1.6 times higher surface coverage compared to polypyrrole. • This copolymer showed 2.5 times lower resistance compared to polypyrrole. • The conjugated structure between Py and FPy causes enhancement of conductivity. • This conducting copolymer has a strong potential to be used in various applications. - Abstract: A direct electrochemical copolymerization of pyrrole–formyl pyrrole (Py–co-FPy) was carried out by oxidative copolymerization of formyl pyrrole and pyrrole in LiClO{sub 4} aqueous solution through galvanostatic method. The (Py–co-FPy) copolymer was characterized using Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscope (FESEM), energy-filtering transmission electron microscope (EFTEM), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The FESEM images showed that the synthesized copolymer had a hollow whelk-like helixes structure, which justifies the enhancement of charge transportation through the copolymer film. Cyclic voltammetry studies revealed that the electrocatalytic activity of synthesized copolymer has improved and the surface coverage in copolymer enhanced 1.6 times compared to polypyrrole alone. Besides, (Py–co-FPy) copolymer showed 2.5 times lower electrochemical charge transfer resistance (R{sub ct}) value in impedance spectroscopy. Therefore, this copolymer has a strong potential to be used in several applications such as sensor applications.

  11. Electrochemical synthesis of poly(pyrrole-co-o-anisidine)/chitosan composite films

    Science.gov (United States)

    Yalçınkaya, Süleyman; Çakmak, Didem

    2017-05-01

    In this study, poly(pyrrole-co-o-anisidine)/chitosan composite films were electrochemically synthesized in various monomers feed ratio (pyrrole: o-anisidine; 9:1, 7:3, 1:1, 3:7 and 1:9) of pyrrole and o-anisidine on the platinum electrode. Electrochemical synthesis of the composite films was carried out via cyclic voltammetry technique. They were characterized by FT-IR, cyclic voltammetry, SEM micrographs, digital images, TGA and DSC techniques. The SEM results indicated that the particle size of the composite decreased with increasing o-anisidine ratio and the films became more likely to be smooth morphology. The TGA results proved that the film of the composite with 1:1 ratio showed highest final degradation temperature and lowest weight loss (83%) compared to copolymer and 9:1 1:9 composite films. The 1:1 composite film had higher thermal stability than copolymer and the other composite films (9:1 1:9). Meanwhile, electrochemical studies exhibited that the 1/9 composite film had good electrochemical stability as well.

  12. Fungal degradation of organophosphorous insecticides

    Energy Technology Data Exchange (ETDEWEB)

    Bumpus, J.A. [Notre Dame Univ., IN (United States); Kakar, S.N.; Coleman, R.D. [Argonne National Lab., IL (United States)

    1992-07-01

    Organophosphorous insecticides are used extensively to treat a variety of pests and insects. Although as a group they are easily degraded by bacteria in the environment, a number of them have half-lives of several months. Little is known about their biodegradation by fungi. We have shown that Phanerochaete chrysosporium can substantially degrade chlorpyrifos, fonofos, and terbufos (27.5%, 12.2%, and 26.6%, respectively) during 18-day incubation in nitrogen-limited stationary cultures. The results demonstrate that the clorinated pyridinyl ring of chlorpyrifos and the phenyl ring of fonofos undergo ring cleavage during biodegradation by the fungus. The usefulness of the fungus system for bioremediation is discussed. 16 refs., 7 figs., 2 tabs.

  13. Fungal degradation of organophosphorous insecticides

    Energy Technology Data Exchange (ETDEWEB)

    Bumpus, J.A. (Notre Dame Univ., IN (United States)); Kakar, S.N.; Coleman, R.D. (Argonne National Lab., IL (United States))

    1992-01-01

    Organophosphorous insecticides are used extensively to treat a variety of pests and insects. Although as a group they are easily degraded by bacteria in the environment, a number of them have half-lives of several months. Little is known about their biodegradation by fungi. We have shown that Phanerochaete chrysosporium can substantially degrade chlorpyrifos, fonofos, and terbufos (27.5%, 12.2%, and 26.6%, respectively) during 18-day incubation in nitrogen-limited stationary cultures. The results demonstrate that the clorinated pyridinyl ring of chlorpyrifos and the phenyl ring of fonofos undergo ring cleavage during biodegradation by the fungus. The usefulness of the fungus system for bioremediation is discussed. 16 refs., 7 figs., 2 tabs.

  14. Decrease of insecticide resistance over generations without exposure to insecticides in Nilaparvata lugens (Hemipteran: Delphacidae).

    Science.gov (United States)

    Yang, Yajun; Dong, Biqin; Xu, Hongxing; Zheng, Xusong; Tian, Junce; Heong, Kongleun; Lu, Zhongxian

    2014-08-01

    The brown planthopper, Nilaparvata lugens (Stål), is one of the most important insect pests on paddy rice in tropical and temperate Asia. Overuse and misuse of insecticides have resulted in the development of high resistance to many different insecticides in this pest. Studies were conducted to evaluate the change of resistance level to four insecticides over 15 generations without any exposure to insecticides in brown planthopper. After 15 generations' rearing without exposure to insecticide, brown planthopper could reverse the resistance to imidacloprid, chlorpyrifos, fipronil, and fenobucarb. The range and style of resistance reversal of brown planthopper differed when treated with four different insecticides. To monitor potential changes in insect physiological responses, we measured the activity of each of the three selected enzymes, including acetylcholinesterases (AChE), general esterases (EST), and glutathione S-transferases. After multiple generations' rearing without exposure to insecticide, AChE and EST activities of brown planthopper declined with the increased generations, suggesting that the brown planthopper population adjusted activities of EST and AChE to adapt to the non-insecticide environment. These findings suggest that the reducing, temporary stop, or rotation of insecticide application could be incorporated into the brown planthopper management.

  15. Transformation of the insecticide teflubenzuron by microorganisms

    NARCIS (Netherlands)

    Finkelstein, Z.I.; Baskunov, B.P.; Rietjens, I.M.C.M.; Boersma, M.G.; Vervoort, J.; Golovleva, L.A.

    2001-01-01

    Transformation of teflubenzuron, the active component in the insecticide commercialized as Nomolt, by soil microorganisms was studied. It was shown that microorganisms, belonging to Bacillus, Alcaligenes, Pseudomonas and Acinetobacter genera are capable to perform the hydrolytic cleavage of the

  16. Modeling global distribution of agricultural insecticides in surface waters.

    Science.gov (United States)

    Ippolito, Alessio; Kattwinkel, Mira; Rasmussen, Jes J; Schäfer, Ralf B; Fornaroli, Riccardo; Liess, Matthias

    2015-03-01

    Agricultural insecticides constitute a major driver of animal biodiversity loss in freshwater ecosystems. However, the global extent of their effects and the spatial extent of exposure remain largely unknown. We applied a spatially explicit model to estimate the potential for agricultural insecticide runoff into streams. Water bodies within 40% of the global land surface were at risk of insecticide runoff. We separated the influence of natural factors and variables under human control determining insecticide runoff. In the northern hemisphere, insecticide runoff presented a latitudinal gradient mainly driven by insecticide application rate; in the southern hemisphere, a combination of daily rainfall intensity, terrain slope, agricultural intensity and insecticide application rate determined the process. The model predicted the upper limit of observed insecticide exposure measured in water bodies (n = 82) in five different countries reasonably well. The study provides a global map of hotspots for insecticide contamination guiding future freshwater management and conservation efforts. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. The electrochemical synthesis of poly(pyrrole-co-o-anisidine) on 3102 aluminum alloy and its corrosion protection properties

    International Nuclear Information System (INIS)

    Mert, B. Dogru; Yazici, B.

    2011-01-01

    Research highlights: → The electrochemical synthesis of strongly adherent, uniform polypyrrole (PPy) and poly(pyrrole-co-o-anisidine) coatings were successfully achieved on 3102 aluminum alloy from 0.1 M monomer (pyrrole and pyrrole:o-anisidine, 8:2) containing oxalic acid by means of the cyclic voltammetry technique. → The results were showed that the water permeation of copolymer coating is lower than PPy. → This study was showed that copolymer is suitable coating for protection of 3102 Al alloy against corrosion. - Abstract: The electrochemical syntheses of polypyrrole (PPy) and poly(pyrrole-co-o-anisidine) were achieved on 3102 aluminum alloy (Al) from 0.1 M monomer (pyrrole:o-anisidine, 8:2) containing 0.4 M oxalic acid solution using the cyclic voltammetry technique. The synthesized films were characterized by FT-IR spectroscopy. The thermal stability of films was determined by thermogravimetric analysis (TGA) technique. Surface morphologies were characterized by scanning electron microscope (SEM) images. The potential of zero charge (pzc) of Al was determined using electrochemical impedance spectroscopy (EIS). The corrosion behavior of samples was investigated with open circuit potential (E ocp )-time, EIS, and anodic polarization techniques. It was found that copolymer coated Al provides better barrier property against of corrosion in 3.5% NaCl solution.

  18. Role of the ribose-specific marker furfuryl-amine in the formation of aroma active 1-(furan-2-ylmethyl)-1H-pyrrole (or furfuryl-pyrrole) derivatives.

    Science.gov (United States)

    Nikolov, Plamen Y; Yaylayan, Varoujan A

    2012-10-10

    Furfuryl-pyrroles possess a diverse range of organoleptic properties described as roasted, chocolaty, green, horseradish-like, and mushroom-like and are detected in various foods such as coffee, chocolate, popcorn, and roasted chicken. Although their origin in food was attributed to furfuryl-amine, the latter has not been detected so far in Maillard model systems or in foods. In this study, furfuryl-amine was shown to be formed specifically from ribose through nitrogen atom transfer from the α-amino group of any amino acid. Such a transfer can be achieved through decarboxylation of the Schiff base adduct and isomerization followed by hydrolysis. Through the use of (15)Nα-lysine it was revealed that only the (15)Nα nitrogen atom was incorporated into its structure, indicating a specific role for the carboxylate moiety in the mechanism of its formation. Furthermore, isotope labeling studies have indicated that furfuryl-pyrrole derivatives can be formed by the interaction of 2 mol of furfuryl-amine with 3-deoxyribosone followed by dehydration and cyclization to form 1-(furan-2-yl)-N-{[1-(furan-2-ylmethyl)-1H-pyrrol-2-yl]methylidene}methanamine. After hydrolysis, this intermediate can generate furfuryl-formyl-pyrrole, furfuryl-pyrrole carboxylic acid, and furfuryl-pyrrole. In this study, the furfuryl-amine derivatives were also detected in different coffee beans after pyrolysis and analysis by GC-MS. The potential of these compounds to form in aqueous model systems at a temperature of 120 °C was also demonstrated.

  19. Malaria Vector Control Still Matters despite Insecticide Resistance.

    Science.gov (United States)

    Alout, Haoues; Labbé, Pierrick; Chandre, Fabrice; Cohuet, Anna

    2017-08-01

    Mosquito vectors' resistance to insecticides is usually considered a major threat to the recent progresses in malaria control. However, studies measuring the impact of interventions and insecticide resistance reveal inconsistencies when using entomological versus epidemiological indices. First, evaluation tests that do not reflect the susceptibility of mosquitoes when they are infectious may underestimate insecticide efficacy. Moreover, interactions between insecticide resistance and vectorial capacity reveal nonintuitive outcomes of interventions. Therefore, considering ecological interactions between vector, parasite, and environment highlights that the impact of insecticide resistance on the malaria burden is not straightforward and we suggest that vector control still matters despite insecticide resistance. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Lipid-Lowering Effects of Ethyl 2-Phenacyl-3-aryl-1H-pyrrole- 4-carboxylates in Rodents

    Directory of Open Access Journals (Sweden)

    Bruce S. Burnham

    2004-02-01

    Full Text Available A series of substituted 2-phenacyl-3-phenyl-1H-pyrrole-4-carboxylates were prepared from substituted acetophenones in 6 steps. The final condensations between a chloroenal and an aminoketone were carried out under neutral conditions in parallel to yield the series listed below. Selected pyrrole derivatives proved to be potent hypolipidemic agents lowering serum triglyceride concentrations in CF-1 male mice after 14 days of I.P. administration. One agent orally lowered serum cholesterol in Sprague-Dawley male rats at 2mg/kg/day after 14 days. The agents demonstrated a lowering of mouse serum LDL- cholesterol levels and selected compounds showed an elevation of serum HDL-cholesterol levels. The cholesterol concentrations in the liver were raised while the cholesterol and triglyceride contents of the aorta were significantly lowered by the selected trisubstituted pyrrole.

  1. Blood Pyrrole-Protein Adducts--A Biomarker of Pyrrolizidine Alkaloid-Induced Liver Injury in Humans.

    Science.gov (United States)

    Ruan, Jianqing; Gao, Hong; Li, Na; Xue, Junyi; Chen, Jie; Ke, Changqiang; Ye, Yang; Fu, Peter Pi-Cheng; Zheng, Jiang; Wang, Jiyao; Lin, Ge

    2015-01-01

    Pyrrolizidine alkaloids (PAs) induce liver injury (PA-ILI) and is very likely to contribute significantly to drug-induced liver injury (DILI). In this study we used a newly developed ultra-high performance liquid chromatography-triple quadrupole-mass spectrometry (UHPLC-MS)-based method to detect and quantitate blood pyrrole-protein adducts in DILI patients. Among the 46 suspected DILI patients, 15 were identified as PA-ILI by the identification of PA-containing herbs exposed. Blood pyrrole-protein adducts were detected in all PA-ILI patients (100%). These results confirm that PA-ILI is one of the major causes of DILI and that blood pyrrole-protein adducts quantitated by the newly developed UHPLC-MS method can serve as a specific biomarker of PA-ILI.

  2. Electrochemical polymerization of pyrrole over AZ31 Mg alloy for biomedical applications

    International Nuclear Information System (INIS)

    Srinivasan, A.; Ranjani, P.; Rajendran, N.

    2013-01-01

    Highlights: ► Polymerization of pyrrole over AZ31 Mg was carried out using cyclic voltammetry. ► Pyrrole concentration was optimized to accomplish the adherent and uniform coating. ► Effect of monomer concentration on the surface morphology was discussed. ► Corrosion resistance of AZ31 Mg in SBF was studied as a function of Py concentration. ► PPy coated AZ31 Mg alloy exhibited enhanced corrosion resistance at 0.25 M of Py. -- Abstract: Electrochemical polymerization of pyrrole (Py) from aqueous salicylate solution over AZ31 Mg alloy was carried out using cyclic voltammetry (CV). The effect of monomer concentration on the surface and electrochemical corrosion in simulated body fluid (SBF) were analysed. Attenuated total reflection-infrared (ATR-IR) spectra showed the characteristic ring stretching peaks for polypyrrole (PPy). Scanning electron microscopy (SEM) and atomic force microscopy (AFM) studies exhibited typical cauliflower morphology with rough surface for PPy coated AZ31 Mg alloy. Open circuit potential measurement and potentiodynamic polarization studies revealed that the coating prepared using 0.25 M of Py had positive shift of about 120 mV in corrosion potential and lower corrosion current density (0.03 mA/cm 2 ) compared to other concentrations and uncoated AZ31 Mg alloy (0.25 mA/cm 2 ). Electrochemical impedance spectroscopic (EIS) studies of uncoated and PPy coated Mg alloy in SBF revealed three-time constants behaviour with about one order of increment in impedance value for 0.25 M of Py

  3. Modeling global distribution of agricultural insecticides in surface waters

    International Nuclear Information System (INIS)

    Ippolito, Alessio; Kattwinkel, Mira; Rasmussen, Jes J.; Schäfer, Ralf B.; Fornaroli, Riccardo; Liess, Matthias

    2015-01-01

    Agricultural insecticides constitute a major driver of animal biodiversity loss in freshwater ecosystems. However, the global extent of their effects and the spatial extent of exposure remain largely unknown. We applied a spatially explicit model to estimate the potential for agricultural insecticide runoff into streams. Water bodies within 40% of the global land surface were at risk of insecticide runoff. We separated the influence of natural factors and variables under human control determining insecticide runoff. In the northern hemisphere, insecticide runoff presented a latitudinal gradient mainly driven by insecticide application rate; in the southern hemisphere, a combination of daily rainfall intensity, terrain slope, agricultural intensity and insecticide application rate determined the process. The model predicted the upper limit of observed insecticide exposure measured in water bodies (n = 82) in five different countries reasonably well. The study provides a global map of hotspots for insecticide contamination guiding future freshwater management and conservation efforts. - Highlights: • First global map on insecticide runoff through modelling. • Model predicts upper limit of insecticide exposure when compared to field data. • Water bodies in 40% of global land surface may be at risk of adverse effects. • Insecticide application rate, terrain slope and rainfall main drivers of exposure. - We provide the first global map on insecticide runoff to surface water predicting that water bodies in 40% of global land surface may be at risk of adverse effects

  4. Tumor Repression of VCaP Xenografts by a Pyrrole-Imidazole Polyamide

    OpenAIRE

    Hargrove, Amanda E.; Martinez, Thomas F.; Hare, Alissa A.; Kurmis, Alexis A.; Phillips, John W.; Sud, Sudha; Pienta, Kenneth J; Dervan, Peter B.

    2015-01-01

    Pyrrole-imidazole (Py-Im) polyamides are high affinity DNA-binding small molecules that can inhibit protein-DNA interactions. In VCaP cells, a human prostate cancer cell line overexpressing both AR and the TMPRSS2-ERG gene fusion, an androgen response element (ARE)-targeted Py-Im polyamide significantly downregulates AR driven gene expression. Polyamide exposure to VCaP cells reduced proliferation without causing DNA damage. Py-Im polyamide treatment also reduced tumor growth in a VCaP mouse ...

  5. Synthesis and spectroscopic characterization of a fluorescent pyrrole derivative containing electron acceptor and donor groups

    Science.gov (United States)

    Almeida, A. K. A.; Monteiro, M. P.; Dias, J. M. M.; Omena, L.; da Silva, A. J. C.; Tonholo, J.; Mortimer, R. J.; Navarro, M.; Jacinto, C.; Ribeiro, A. S.; de Oliveira, I. N.

    2014-07-01

    The synthesis and fluorescence characterization of a new pyrrole derivative (PyPDG) containing the electron donor-acceptor dansyl substituent is reported. The effects of temperature and solvent polarity on the steady-state fluorescence of this compound are investigated. Our results show that PyPDG exhibits desirable fluorescent properties which makes it a promising candidate to be used as the photoactive material in optical thermometry and thermography applications. Further, the electrochemical and emission properties of polymeric films obtained from the oxidation polymerization of PyPDG are also analyzed.

  6. Kinetics of tritium isotope exchange between liquid pyrrole and gaseous hydrogen

    International Nuclear Information System (INIS)

    Stolarz, A.

    1994-01-01

    The kinetics of tritium isotope exchange between liquid pyrrole and gaseous hydrogen has been studied over the temperature range of 290-303 K. The reaction was carried out in the presence of platinum black but in spite of that, it appeared to be relatively slow. The kinetics of the exchange reaction studied could be described by the simple McKay equation. The results obtained suggest that diffusion is the rate-determining step. A mechanism of exchange is proposed. (author) 10 refs.; 2 figs.; 1 tab

  7. Synthesis and Physical Characterization of Carbon Nano tubes Coated by Conducting Poly pyrrole

    International Nuclear Information System (INIS)

    Talib, A.B.Z.A.; Wan Mahmood Mat Yunus; Kasar Behzad; Nayereh Soltani

    2011-01-01

    This study describes the preparation of poly pyrrole multi walled carbon nano tube (PPy/ MWNT) composites by in situ chemical oxidative polymerization. Various ratios of functionalized MWNTs are dispersed in the water, and PPy are then synthesized via in-situ chemical oxidative polymerization on the surface of the carbon nano tubes. The morphology of the resulting complex nano tubes (MWNT-PPY) was characterized by scanning electron microscopy (SEM). The conductivity of each composite showed a maximum in the temperature scale of 120- 160 degree Celsius and then decreased dramatically with the increase of temperature. (author)

  8. Ultrasound-assisted green synthesis of pyrroles and pyridazines in water via three-component condensation reactions of arylglyoxals

    Directory of Open Access Journals (Sweden)

    Bagher Eftekhari-Sis

    2013-04-01

    Full Text Available A green and efficient method for the preparation of 5-aryl-4-hydroxy-2-methyl-1H-pyrrole-3-carboxylic acid esters and 6-aryl-3-methylpyridazine-4-carboxylic acid esters via three-component reaction of arylglyoxal hydrates with β-dicarbonyl compounds in the presence of ammonium acetate and hydrazine hydrate using water as solvent under ultrasonic irradiation was reported. The reactions proceeded rapidly and afforded the corresponding pyrroles and pyridazines in good to high yields in very short reaction time.

  9. Neurobehavioral toxicology of pyrethroid insecticides

    International Nuclear Information System (INIS)

    Crofton, K.M.

    1986-01-01

    Pyrethroid insecticides are classified as either Type I or Type II based upon in vivo toxic signs, and neurophysiological and biochemical data. Both axonal sodium channels and the γ-aminobutyric acid (GABA) receptor complex have been proposed as the major site of action of the Type II pyrethroids. This investigation characterized the behavior and biochemical effects of low dosages of pyrethroids in rats. Type I and II pyrethroids were tested for effects on figure-eight maze activity and the acoustic startle response (ASR). All compounds decreased figure-eight maze activity. Interactions of Type I and II pyrethroids with the three major binding sites on the GABA complex were determined in vivo. Radioligand binding experiments assessed in vitro interactions of pyrethroids with the three major GABA-complex binding sites. None of the pyrethroids competed for [ 3 H]-muscimol or [ 3 H]-flunitrazepam binding. Only Type II pyrethroids inhibited binding of [ 35 S]-t-butylbicyclophosphorothionate (TBPS) in cortical synaptosome preparations with K/sub i/ values of 5 to 10 μM. The [ 35 S]-TBPS data implicate the TBPS/picrotoxinin binding site in the mechanism of Type II pyrethroid toxicity. The results of these experiments support the classification of pyrethroids into two classes, and demonstrate the utility of the figure-eight maze and the ASR in studies to elucidate neurotoxic mechanisms. The interaction of the Type II pyrethroids is probably restricted to the TBPS/picrotoxinin binding domain on the GABA complex as shown by both the in vivo and in vitro studies

  10. Poly(1-(2-carboxyethyl)pyrrole)/polypyrrole composite nanowires for glucose biosensor

    International Nuclear Information System (INIS)

    Jiang Hairong; Zhang Aifeng; Sun Yanan; Ru Xiaoning; Ge Dongtao; Shi Wei

    2012-01-01

    A novel glucose biosensor based on poly(1-(2-carboxyethyl)pyrrole) (PPyCOOH)/polypyrrole (PPy) composite nanowires was developed by immobilizing glucose oxidase (GOD) on the nanowires via covalent linkages. The PPyCOOH/PPy composite nanowires were fabricated by a facile two-step electrochemical synthesis route. First, PPy nanowires were synthesized in phosphate buffer solution using organic sulfonic acid, p-toluenesulfonate acid, as soft-template. Then, PPyCOOH/PPy composite nanowires were obtained by polymerizing 1-(2-carboxyethyl)pyrrole onto PPy nanowires via electrochemical method. Scanning electron microscopic, FT-IR spectra, X-ray photoelectron spectroscopy and cyclic voltammograms were used to characterize the structural and electrical behaviors of the composite nanowires. The PPyCOOH/PPy composite nanowires exhibited uniform diameter, high reactive site (-COOH), large specific surface, excellent electroactivity and good adhesion to electrode. The glucose biosensor was constructed by covalently coupling GOD to the composite nanowires. The biosensor response was rapid (5 s), highly sensitive (33.6 μA mM −1 cm −2 ) with a wide linear range (up to 10.0 mM) and low detection limit (0.63 μM); it also exhibited high stability and specificity to glucose. The attractive electrochemical and structural properties of PPyCOOH/PPy composite nanowires suggested potential application for electrocatalysis and biosensor.

  11. Influencing the electronic interaction in diferrocenyl-1-phenyl-1H-pyrroles.

    Science.gov (United States)

    Hildebrandt, Alexander; Lang, Heinrich

    2011-11-28

    Functionalised diferrocenyl-1-phenyl-1H-pyrroles were synthesised using Negishi C,C cross-coupling reactions. The influence of different substituents at the phenyl moiety on the electronic interaction was studied using electrochemistry (cyclic and square-wave voltammetry) and spectro-electrochemistry (in situ UV/Vis-NIR spectroscopy). The ferrocenyl moieties gave rise to two sequential, reversible redox processes in each of the diferrocenyl-1-phenyl-1H-pyrroles. The observed ΔE(1/2) values (ΔE(1/2) = difference between first and second oxidation) range between 420 and 480 mV. A linear relationship between the Hammett constants σ of the substituents and the separation of the redox potentials exists. The NIR measurements confirm electronic communication between the iron centers as intervalence charge transfer (IVCT) absorptions were observed in the corresponding mixed-valent monocationic species. All compounds were classified as class II systems according to Robin and Day (M. B. Robin and P. Day, Adv. Inorg. Chem., 1967, 10, 247-423). The oscillator strength of the charge transfer transition highly depends on the electron donating or electron withdrawing character of the phenyl substituents. This enables direct tuning of the intermetallic communication by simple modification of the molecule's functional group. Hence, this series of molecules may be regarded as model compounds for single molecule transistors.

  12. Heterogeneous hydrogenation using stable and reusable calix[4]pyrrole fenced Pt nanoparticles and its mechanistic insight

    Science.gov (United States)

    Kongor, Anita; Panchal, Manthan; Athar, Mohd; Mehta, Viren; Bhatt, Keyur; Jha, P. C.; Jain, Vinod

    2018-04-01

    Novel calix[4]pyrrole encapsulated platinum nanoparticles (PtNPs) have been prepared in the aqueous medium using meso-tetra(methoxy) meso-tetra (4-phenoxy acetohydrazide) calix[4]pyrrole (MCPTH) as both reducing as well as the capping agent. The developed MCPTH-PtNPs nano-assembly has been characterized by HRTEM, XRD, XPS, TGA and FTIR methods. Grafting capability of MCPTH on PtNPs was envisaged by molecular dynamics simulations that renders towards the complemented role of ligand in capping the surface via metal-acceptor interactions. These nanoparticles have been exploited for chemoselective hydrogenation of nitroarenes using molecular hydrogen at room temperature. Supplemented computational and experimental apprehension clearly corroborates that hydrazide group remains in close contact with the surface and provides adequate coordination sites for the adsorption of nitrenes; required for hydrogenation. This catalytic approach can be conceived as an important tool for determining the electronic and structural influence on the catalytic activity which may open new vistas pertaining to the use of calix functionalized nanocatalyst.

  13. Acids and alkali resistant sticky superhydrophobic surfaces by one-pot electropolymerization of perfluoroalkyl alkyl pyrrole.

    Science.gov (United States)

    Nicolas, Mael

    2010-03-15

    Over the past few years, electropolymerization of semifluorinated monomers like thiophene or pyrrole has been used as a gentle and effective method to generate, in one step, stable superhydrophobic surfaces. The synthetic route mostly involves the coupling reaction between a carboxylic acid and an alcohol, using a carboxy group-activated reagent and a catalyst. As a consequence, the electroformed surfaces present high liquid repellency due to the concomitant effect of roughness and low surface energy. Nevertheless, the ester connector can be cleaved under acidic and basic conditions, preventing its use under a range of environmental conditions. To overcome this drawback, a new perfluoroalkyl alkyl pyrrole has been synthesized, the fluorinated segment being connected to the electropolymerizable part via an alkyl chain, and electropolymerized, leading to surfaces that exhibit a static contact angle with water superior to 150 degrees and no sliding angle, over a wide pH range and with a long lifetime. This represents the first example of a pure conducting polymer surface with sticky superhydrophobicity not only in pure water but also in corrosive solutions such as acids and bases, giving rise to new prospects in practical applications. 2009 Elsevier Inc. All rights reserved.

  14. Insecticide susceptibility status of human biting mosquitoes in ...

    African Journals Online (AJOL)

    Background: There has been a rapid emergence in insecticide resistance among mosquito population to commonly used public health insecticides. This situation presents a challenge to chemicals that are currently used to control mosquitoes in sub-Saharan African. Furthermore, there is limited information on insecticide ...

  15. Microbes as interesting source of novel insecticides: A review ...

    African Journals Online (AJOL)

    ... strains with good insecticidal properties can be identified, evaluated and utilized for pest control. This paper reviews the insecticidal properties of microbes and their potential utility in pest management. Keywords: Microbes, insecticides, metabolites, pest management. African Journal of Biotechnology, Vol 13(26) 2582- ...

  16. Metabolic control of the insecticides safety use

    Directory of Open Access Journals (Sweden)

    L.I. Solomenko

    2016-06-01

    Full Text Available The results of the conducted research affirm that the phosphororganic insecticides utilization can lead to the break in the nitrogen metabolism, breaking the protein formation, reducing the protein molecules renewal, causing the amino acid and amides accumulation in the active state. It has been revealed that the translocation and transformation of the insecticides under consideration are more closely connected with the changes of insoluble protein fraction. The stagnation point of the Phosphamide and Kaunter impact on the plant has been determined. And only the use of the preparation in optimal norms can influence stimulatingly the course of the process under consideration.

  17. Sustainable Pathways to Pyrroles through Iron-Catalyzed N-Heterocyclization from Unsaturated Diols and Primary Amines

    NARCIS (Netherlands)

    Yan, Tao; Barta, Katalin

    2016-01-01

    Pyrroles are prominent scaffolds in pharmaceutically active compounds and play an important role in medicinal chemistry. Therefore, the development of new, atom-economic, and sustainable catalytic strategies to obtain these moieties is highly desired. Direct catalytic pathways that utilize readily

  18. Cation-pi interaction of the univalent silver cation with meso-octamethylcalix[4]pyrrole: Experimental and theoretical study

    Czech Academy of Sciences Publication Activity Database

    Polášek, Miroslav; Kvíčala, J.; Makrlík, E.; Křížová, Věra; Vaňura, P.

    2017-01-01

    Roč. 1130, FEB 2017 (2017), s. 408-413 ISSN 0022-2860 Grant - others:GA MŠk(CZ) 20/2015; GA MŠk(CZ) LM2010005 Institutional support: RVO:61388955 Keywords : silver cation * meso-octamethylcalix[4]pyrrole * complexation Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.753, year: 2016

  19. Effect of selected insecticides on SF9 insect cell line

    International Nuclear Information System (INIS)

    Saleh, M.; Rahmo, A.; Hajjar, J.

    2013-01-01

    The toxic effect of three insecticides: dimethoate (organophosphate insecticide), acetamiprid (neonicotinoid insecticide) and deltamethrin (pyrethroid insecticide) were evaluated in vitro on cultured Sf9 cell line. Cell growth inhibition was measured by the 3- (4,5- dimethylthiazol - 2-yl) - 2,5 - diphenyl tetrazolium bromide (MTT) assay. Regression Analysis was used to estimate the 20% inhibition of cells growth (IC 20). The IC 20 values obtained for deltamethrin, acetamipridand dimethoate were: 46.8, 61.6 and 68.9 μM, respectively. The proportion of phagocytic cells was positively correlated with the applied concentrations of the insecticides. (author)

  20. Possibilities of Botanical Insecticides in Plant Protection

    Czech Academy of Sciences Publication Activity Database

    Pavela, R.; Sajfrtová, Marie; Sovová, Helena; Bárnet, M.

    2008-01-01

    Roč. 2, č. 1 (2008), s. 16-23 ISSN 1313-2563 Grant - others:MŠk(CZ) 2B08049 Institutional support: RVO:67985858 Keywords : botanical insecticides * plant extracts * supercritical fluid extraction Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection

  1. Possibilities of Botanical Insecticides in Plant Protection

    Czech Academy of Sciences Publication Activity Database

    Pavela, R.; Sajfrtová, Marie; Sovová, Helena; Bárnet, M.

    2008-01-01

    Roč. 2, č. 1 (2008), s. 16-23 ISSN 1313-2563 Grant - others:GA MŠMT(CZ) 2B08049 Institutional research plan: CEZ:AV0Z40720504 Keywords : botanical insecticides * plant exctracts * supercritical fluid extraction Subject RIV: GF - Plant Pathology, Vermin, Weed, Plant Protection

  2. Insecticidal and fungicidal compounds from Isatis tinctoria.

    Science.gov (United States)

    Seifert, K; Unger, W

    1994-01-01

    Tryptanthrin (1), indole-3-acetonitrile (2) and p-coumaric acid methylester (3) were isolated from the aerial parts of Isatis tinctoria L. The compounds show insecticidal and anti-feedant activity against termites (Reticulitermis santonensis), insect preventive and control activity against larvae of the house longhorn beetle (Hylotrupes bajulus) and fungicidal activity against the brown-rot fungus (Coniophora puteana).

  3. Is Apis mellifera more sensitive to insecticides than other insects?

    Science.gov (United States)

    Hardstone, Melissa C; Scott, Jeffrey G

    2010-11-01

    Honey bees (Apis mellifera L.) are among the most important pollinators in natural and agricultural settings. They commonly encounter insecticides, and the effects of insecticides on honey bees have been frequently noted. It has been suggested that honey bees may be (as a species) uniquely sensitive to insecticides, although no comparative toxicology study has been undertaken to examine this claim. An extensive literature review was conducted, using data in which adult insects were topically treated with insecticides. The goal of this review was to summarize insecticide toxicity data between A. mellifera and other insects to determine the relative sensitivity of honey bees to insecticides. It was found that, in general, honey bees were no more sensitive than other insect species across the 62 insecticides examined. In addition, honey bees were not more sensitive to any of the six classes of insecticides (carbamates, nicotinoids, organochlorines, organophosphates, pyrethroids and miscellaneous) examined. While honey bees can be sensitive to individual insecticides, they are not a highly sensitive species to insecticides overall, or even to specific classes of insecticides. However, all pesticides should be used in a way that minimizes honey bee exposure, so as to minimize possible declines in the number of bees and/or honey contamination. Copyright © 2010 Society of Chemical Industry.

  4. Synthesis of novel synthetic intermediates from the reaction of benzimidazole and triazole carbenes with ketenimines and their application in the construction of spiro-pyrroles.

    Science.gov (United States)

    Mo, Jun-Ming; Ma, Yang-Guang; Cheng, Ying

    2009-12-07

    2-(2-Alkoxycarbonyl-1-arylamino-1-propenyl)benzimidazolium and 5-(2-alkoxycarbonyl-1-arylamino-1-propenyl)triazolium salts were synthesized in good yields from the reaction of benzimidazole and triazole carbenes with ketenimines. Upon treatment with a base, both salts were converted into novel 1,3-dipoles which underwent [3+2] cycloaddition reactions with electron-deficient alkynes and allenes to produce benzimidazole-spiro-pyrroles or triazole-spiro-pyrroles. This work provides novel synthons for the construction of multifunctional spiro-pyrrole derivatives that are not easy accessible by other synthetic methods and are potentially amenable to further transformations.

  5. Novel composite materials synthesized by the high-temperature interaction of pyrrole with layered oxide matrices

    Science.gov (United States)

    Pavel, Alexandru Cezar

    The initial goal of the research presented herein was to develop the very first synthetic metal---high-temperature superconductor ceramic composite material, in the specific form of a polypyrrole---Bi2Sr2CaCu 2O8+delta nanocomposite. In the course of scientific investigation, this scope was broadened to encompass structurally and compositionally similar layered bismuthates and simpler layered oxides. The latter substrates were prepared through novel experimental procedures that enhanced the chance of yielding nanostructured morphologies. The designed novel synthesis approaches yielded a harvest of interesting results that may be further developed upon their dissemination in the scientific community. High-temperature interaction of pyrrole with molybdenum trioxide substrates with different crystalline phases and morphologies led to the formation of the first members of a new class of heterogeneous microcomposites characterized by incomplete occupancy by the metal oxide core of the volume encapsulated by the rigid, amorphous permeable polymeric membrane that reproduces the volume of the initial grain of precursor substrate. The method may be applied for various heterogeneous catalyst substrates for the precise determination of the catalytically active crystallographic planes. In a different project, room-temperature, templateless impregnation of molybdenum trioxide substrates with different crystalline phases and morphologies by a large excess of silver (I) cations led to the formation of 1-D nanostructured novel Ag-Mo-O ternary phase in what may be the simplest experimental procedure available to date that has yielded a 1-D nanostructure, regardless the nature of the constituent material. Interaction of this novel ternary phase with pyrrole vapors at high reaction temperatures led to heterogeneous nanostructured composites that exhibited a silver nanorod core. Nanoscrolls of vanadium pentoxide xerogel were synthesized through a novel, facile reflux-based method that

  6. Tumor Repression of VCaP Xenografts by a Pyrrole-Imidazole Polyamide.

    Directory of Open Access Journals (Sweden)

    Amanda E Hargrove

    Full Text Available Pyrrole-imidazole (Py-Im polyamides are high affinity DNA-binding small molecules that can inhibit protein-DNA interactions. In VCaP cells, a human prostate cancer cell line overexpressing both AR and the TMPRSS2-ERG gene fusion, an androgen response element (ARE-targeted Py-Im polyamide significantly downregulates AR driven gene expression. Polyamide exposure to VCaP cells reduced proliferation without causing DNA damage. Py-Im polyamide treatment also reduced tumor growth in a VCaP mouse xenograft model. In addition to the effects on AR regulated transcription, RNA-seq analysis revealed inhibition of topoisomerase-DNA binding as a potential mechanism that contributes to the antitumor effects of polyamides in cell culture and in xenografts. These studies support the therapeutic potential of Py-Im polyamides to target multiple aspects of transcriptional regulation in prostate cancers without genotoxic stress.

  7. Emission and absorption of light in poly pyrrole synthesized by plasma

    International Nuclear Information System (INIS)

    Enriquez, M.A.; Colin, E.; Olayo, M.G.; Cruz, G.J.; Ordonez, E.; Benavides, R.; Morales, J.; Olayo, R.

    2007-01-01

    The poly pyrrole structure (PPy) consists of heterocyclic rings with conjugation that it depends on the intensity of the electric field applied during the synthesis, and its luminescence is related with the π-π * transitions of that conjugation. To irradiate with light of different wavelengths, the results indicate that the polymer absorbs in the interval from 290 to 700 nm and it emits between 450 and 470 nm. The basal conductivity of the polymers, without electromagnetic excitation, it was measured in 10 -15 S/cm, however, to interact with visible light it is increased approximately 10 times and when excite with UV light it is increased up to 3 magnitude orders. (Author)

  8. Lack of effect of deferoxamine, dimethyl sulfoxide, and catalase on monocrotaline pyrrole pulmonary injury

    Energy Technology Data Exchange (ETDEWEB)

    Bruner, L.H.; Johnson, K.; Carpenter, L.J.; Roth, R.A.

    1987-01-01

    Monocrotaline pyrrole (MCTP) is a reactive metabolite of the pyrrolizidine alkaloid monocrotaline. MCTP given intravenously to rats causes pulmonary hypertension and right ventricular hypertrophy. Lesions in lungs after MCTP treatment contain macrophages and neutrophils, which may contribute to the damage by generation of reactive oxygen metabolites. Rats were treated with MCTP and agents known to protect against oxygen radical-mediated damage in acute models of neutrophil-dependent lung injury. Rats received MCTP and deferoxamine mesylate (DF), dimethyl sulfoxide (DMSO), or polyethylene glycol-coupled catalase (PEG-CAT). MCTP/vehicle-treated controls developed lung injury manifested as increased lung weight, release of lactate dehydrogenase into the airway, and sequestration of SVI-labeled bovine serum albumin in the lungs. Cotreatment of rats with DF, DMSO, or PEG-CAT did not protect against the injury due to MCTP. These results suggest that toxic oxygen metabolites do not play an important role in the pathogenesis of MCTP-induced pulmonary injury.

  9. Gamma irradiation effect on polymers derived of pyrrole synthesized by plasma

    International Nuclear Information System (INIS)

    Lopez G, O. G.

    2013-01-01

    This work studies the effect of gamma irradiation at doses of 50, 100, 200, 400 and 800 kGy on polymers obtained from pyrrole synthesized by plasma. The evolution of the structure was studied by Fourier transform infrared spectroscopy (Ftir) and X-ray photoelectron spectroscopy (XPS). The Ftir spectra show that poly pyrroles have N-H, C-H, C=O, triple and consecutive double bonds in their structure. The irradiated polymers show the same chemical groups in their structure without significant changes. Nevertheless, a more detailed analysis by XPS allows the identification of superficial chemical states, such as: C=CH-C, C=CC-C, C-NH-C, C-NC-C, etc., and shows that most of these states are present in all polymers but with different participation. One possible mechanism indicates that as the irradiation dose increases, dehydrogenation processes are performed increasing fragmentation, crosslinking and formation of multiple bonds. The fragmentation and thermal degradation were studied by thermogravimetric analysis, indicating that the loss of moisture and light compounds formed during gamma irradiation occurs in the firsts 100 grades C. The main degradation of all polymers occurs from 150 to 700 grades C, suggesting that the thermal stability is independent of the irradiation dose in the interval studied. Morphology was studied using scanning electron microscopy techniques. Before irradiation, the polymer presented a uniform and practically smooth surface, however, after gamma irradiation, the applied energy increased roughness and macro fragmentation. The roughness and functional groups on the surface reduced the contact angle with water as the irradiation dose increased. However, the polymers are hydrophilic, because for all doses that contact angle is smaller than 90 grades C. Electrical conductivity was calculated respect to temperature in the interval from 25 to 100 grades C. Conductivity increases with temperature and is slightly greater in the irradiated polymers

  10. Catalytic formal [2+2+1] synthesis of pyrroles from alkynes and diazenes via Ti(II)/Ti(IV) redox catalysis.

    Science.gov (United States)

    Gilbert, Zachary W; Hue, Ryan J; Tonks, Ian A

    2016-01-01

    Pyrroles are structurally important heterocycles. However, the synthesis of polysubstituted pyrroles is often challenging. Here, we report a multicomponent, Ti-catalysed formal [2+2+1] reaction of alkynes and diazenes for the oxidative synthesis of penta- and trisubstituted pyrroles: a nitrenoid analogue to classical Pauson-Khand-type syntheses of cyclopentenones. Given the scarcity of early transition-metal redox catalysis, preliminary mechanistic studies are presented. Initial stoichiometric and kinetic studies indicate that the mechanism of this reaction proceeds through a formally Ti(II)/Ti(IV) redox catalytic cycle, in which an azatitanacyclobutene intermediate, resulting from [2+2] alkyne + Ti imido coupling, undergoes a second alkyne insertion followed by reductive elimination to yield pyrrole and a Ti(II) species. The key component for catalytic turnover is the reoxidation of the Ti(II) species to a Ti(IV) imido via the disproportionation of an η(2)-diazene-Ti(II) complex.

  11. Exploration of Novel Botanical Insecticide Leads: Synthesis and Insecticidal Activity of β-Dihydroagarofuran Derivatives.

    Science.gov (United States)

    Zhao, Ximei; Xi, Xin; Hu, Zhan; Wu, Wenjun; Zhang, Jiwen

    2016-02-24

    The discovery of novel leads and new mechanisms of action is of vital significance to the development of pesticides. To explore lead compounds for botanical insecticides, 77 β-dihydroagarofuran derivatives were designed and synthesized. Their structures were mainly confirmed by (1)H NMR, (13)C NMR, DEPT-135°, IR, MS, and HRMS. Their insecticidal activity was evaluated against the third-instar larvae of Mythimna separata Walker, and the results indicated that, of these derivatives, eight exhibited more promising insecticidal activity than the positive control, celangulin-V. Particularly, compounds 5.7, 6.6, and 6.7 showed LD50 values of 37.9, 85.1, and 21.1 μg/g, respectively, which were much lower than that of celangulin-V (327.6 μg/g). These results illustrated that β-dihydroagarofuran ketal derivatives can be promising lead compounds for developing novel mechanism-based and highly effective botanical insecticides. Moreover, some newly discovered structure-activity relationships are discussed, which may provide some important guidance for insecticide development.

  12. Ion channels: molecular targets of neuroactive insecticides.

    Science.gov (United States)

    Raymond-Delpech, Valérie; Matsuda, Kazuhiko; Sattelle, Benedict M; Rauh, James J; Sattelle, David B

    2005-11-01

    Many of the insecticides in current use act on molecular targets in the insect nervous system. Recently, our understanding of these targets has improved as a result of the complete sequencing of an insect genome, i.e., Drosophila melanogaster. Here we examine the recent work, drawing on genetics, genomics and physiology, which has provided evidence that specific receptors and ion channels are targeted by distinct chemical classes of insect control agents. The examples discussed include, sodium channels (pyrethroids, p,p'-dichlorodiphenyl-trichloroethane (DDT), dihydropyrazoles and oxadiazines); nicotinic acetylcholine receptors (cartap, spinosad, imidacloprid and related nitromethylenes/nitroguanidines); gamma-aminobutyric acid (GABA) receptors (cyclodienes, gamma-BHC and fipronil) and L-glutamate receptors (avermectins). Finally, we have examined the molecular basis of resistance to these molecules, which in some cases involves mutations in the molecular target, and we also consider the future impact of molecular genetic technologies in our understanding of the actions of neuroactive insecticides.

  13. Mixture for Controlling Insecticide-Resistant Malaria Vectors

    OpenAIRE

    Pennetier, Cédric; Costantini, Carlo; Corbel, Vincent; Licciardi, Séverine; Dabire, R. K.; Lapied, B.; Chandre, Fabrice; Hougard, Jean-Marc

    2008-01-01

    The spread of resistance to pyrethroids in the major Afrotropical malaria vectors Anopheles gambiae s.s. necessitates the development of new strategies to control resistant mosquito populations. To test the efficacy of nets treated with repellent and insecticide against susceptible and insecticide-resistant An. gambiae mosquito populations, we impregnated mosquito bed nets with an insect repellent mixed with a low dose of organophosphorous insecticide and tested them in a rice-growing area ne...

  14. SPECTROSCOPIC STUDY OF EFFECTS OF TETRAALKYLAMMONIUM CATIONS ON F--SENSING PROPERTIES OF CALIX[4]PYRROLE BORADIAZAINDACENE DYE

    Directory of Open Access Journals (Sweden)

    Yongjun Lv

    Full Text Available A novel meso-tetracyclohexylcalix[4]pyrrole-based boradiazaindacene dye 3 was synthesized and characterized. F--binding properties of the dye in the presence of tetrabutylammonium (TBA+, tetraethylammonium (TEA+, and tetramethylammonium (TMA+ counter ions were investigated by UV-Vis, fluorescence, and NMR spectroscopies. Dye 3 displayed various degrees of absorption red shift, fluorescence quenching, and downfield shifts of NH signals for the three fluoride salts. The association constants of these salts mainly depend on cation size effects and ion-pairing effects and were in the order KTMA+ > KTEA+ > KTBA+. Thus, we speculate that both F- and tetraalkylammonium cations are concomitantly located above and below a bowl-shaped calix[4]pyrrole cup in an ion-paired complex, respectively.

  15. Ethyl 5-cyano-4-[2-(2,4-dichlorophenoxyacetamido]-1-phenyl-1H-pyrrole-3-carboxylate

    Directory of Open Access Journals (Sweden)

    Jing Xu

    2009-08-01

    Full Text Available In the title compound, C22H17Cl2N3O4, the pyrrole ring and the 2,4-dichlorophenyl group form a dihedral angle of 8.14 (13°; the phenyl ring is twisted with respect to the pyrrole ring, forming a dihedral angle of 60.77 (14°. The C=O bond length is 1.213 (3 Å, indicating that the molecule is in the keto form, associated with a –CONH– group, and the amide group adopts the usual trans conformation. The molecule is stabilized by an intramolecular N—H...O hydrogen-bonding interaction. In the crystal, the stacked molecules exhibit intermolecular C—H...O and C—H...N hydrogen-bonding interactions.

  16. Preparation and enhanced electrochemical properties of nano-sulfur/poly(pyrrole-co-aniline) cathode material for lithium/sulfur batteries

    International Nuclear Information System (INIS)

    Qiu Linlin; Zhang Shichao; Zhang Lan; Sun, Mingming; Wang Weikun

    2010-01-01

    Poly(pyrrole-co-aniline) (PPyA) copolymer nanofibers were prepared by chemical oxidation method with cetyltrimethyl ammonium chloride (CTAC) as template, and the nano-sulfur/poly(pyrrole-co-aniline) (S/PPyA) composite material in lithium batteries was achieved via co-heating the mixture of PPyA and sublimed sulfur at 160 deg. C for 24 h. The component and structure of the materials were characterized by FTIR, Raman, XRD, and SEM. PPyA with nanofiber network structure was employed as a conductive matrix, adsorbing agent and firm reaction chamber for the sulfur cathode materials. The nano-dispersed composite exhibited a specific capacity up to 1285 mAh g -1 in the initial cycle and remained 866 mAh g -1 after 40 cycles.

  17. Regioselective C2 Oxidative Olefination of Indoles and Pyrroles through Cationic Rhodium(III)-Catalyzed C-H Bond Activation.

    Science.gov (United States)

    Li, Bin; Ma, Jianfeng; Xie, Weijia; Song, Haibin; Xu, Shansheng; Wang, Baiquan

    2013-09-02

    Be economic with your atoms! An efficient Rh-catalyzed oxidative olefination of indoles and pyrroles with broad substrate scope and tolerance is reported. The catalytic reaction proceeds with excellent regio- and stereoselectivity. The directing group N,N-dimethylcarbamoyl was crucial for the reaction and could be removed easily. Copyright © 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Direct detection of pyridine formation by the reaction of CH (CD) with pyrrole: a ring expansion reaction

    Energy Technology Data Exchange (ETDEWEB)

    Soorkia, Satchin; Taatjes, Craig A.; Osborn, David L.; Selby, Talitha M.; Trevitt, Adam J.; Wilson, Kevin R.; Leone, Stephen R.

    2010-03-16

    The reaction of the ground state methylidyne radical CH (X2Pi) with pyrrole (C4H5N) has been studied in a slow flow tube reactor using Multiplexed Photoionization Mass Spectrometry coupled to quasi-continuous tunable VUV synchrotron radiation at room temperature (295 K) and 90 oC (363 K), at 4 Torr (533 Pa). Laser photolysis of bromoform (CHBr3) at 248 nm (KrF excimer laser) is used to produce CH radicals that are free to react with pyrrole molecules in the gaseous mixture. A signal at m/z = 79 (C5H5N) is identified as the product of the reaction and resolved from 79Br atoms, and the result is consistent with CH addition to pyrrole followed by Helimination. The Photoionization Efficiency curve unambiguously identifies m/z = 79 as pyridine. With deuterated methylidyne radicals (CD), the product mass peak is shifted by +1 mass unit, consistent with the formation of C5H4DN and identified as deuterated pyridine (dpyridine). Within detection limits, there is no evidence that the addition intermediate complex undergoes hydrogen scrambling. The results are consistent with a reaction mechanism that proceeds via the direct CH (CD) cycloaddition or insertion into the five-member pyrrole ring, giving rise to ring expansion, followed by H atom elimination from the nitrogen atom in the intermediate to form the resonance stabilized pyridine (d-pyridine) molecule. Implications to interstellar chemistry and planetary atmospheres, in particular Titan, as well as in gas-phase combustion processes, are discussed.

  19. Pyrrole PMOs, incorporating new N-heterocyclic compounds on an ethene-PMO through Diels–Alder reactions

    Energy Technology Data Exchange (ETDEWEB)

    Esquivel, Dolores; De Canck, Els [Center for Ordered Materials, Organometallics and Catalysis, Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent (Belgium); Jiménez-Sanchidrián, César [Department of Organic Chemistry, Nanochemistry and Fine Chemistry Research Institute (IUIQFN), Faculty of Sciences, University of Córdoba, Campus de Rabanales, Marie Curie Building, Ctra. Nnal. IV, km 396, 14071 Córdoba (Spain); Romero-Salguero, Francisco J., E-mail: qo2rosaf@uco.es [Department of Organic Chemistry, Nanochemistry and Fine Chemistry Research Institute (IUIQFN), Faculty of Sciences, University of Córdoba, Campus de Rabanales, Marie Curie Building, Ctra. Nnal. IV, km 396, 14071 Córdoba (Spain); Van Der Voort, Pascal, E-mail: pascal.vandervoort@ugent.be [Center for Ordered Materials, Organometallics and Catalysis, Department of Inorganic and Physical Chemistry, Ghent University, Krijgslaan 281-S3, 9000 Ghent (Belgium)

    2014-11-14

    The ethenylene bridges on the walls of an ethenylene-bridged periodic mesoporous organosilica were successfully modified with a variety of pyrrole derivatives – pyrrole, methylpyrrole, dimethylpyrrole, trimethylpyrrole and 1-phenylpyrrole – through Diels–Alder reactions. X-ray diffraction measurements and N{sub 2} adsorption–desorption analysis confirmed the preservation of the ordering and mesoporosity of the parent material as well as the decoration of the pores with the surface Diels–Alder adducts. Moreover, other techniques such as DRIFT, {sup 13}C and {sup 29}Si nuclear magnetic resonances revealed the formation of the surface N-heterocyclic compounds at the parent ethenylene sites. - Highlights: • Chemical modification of the double bonds on an ethene-PMO through the Diels–Alder reaction. • A family of pyrrole derivatives act as dienes in the Diels–Alder reaction. • Well-ordering and mesoporosity are retained after the post-functionalization. • N-containing compounds on the surface of ethene-PMO are present after the Diels–Alder reaction.

  20. Pyrrole PMOs, incorporating new N-heterocyclic compounds on an ethene-PMO through Diels–Alder reactions

    International Nuclear Information System (INIS)

    Esquivel, Dolores; De Canck, Els; Jiménez-Sanchidrián, César; Romero-Salguero, Francisco J.; Van Der Voort, Pascal

    2014-01-01

    The ethenylene bridges on the walls of an ethenylene-bridged periodic mesoporous organosilica were successfully modified with a variety of pyrrole derivatives – pyrrole, methylpyrrole, dimethylpyrrole, trimethylpyrrole and 1-phenylpyrrole – through Diels–Alder reactions. X-ray diffraction measurements and N 2 adsorption–desorption analysis confirmed the preservation of the ordering and mesoporosity of the parent material as well as the decoration of the pores with the surface Diels–Alder adducts. Moreover, other techniques such as DRIFT, 13 C and 29 Si nuclear magnetic resonances revealed the formation of the surface N-heterocyclic compounds at the parent ethenylene sites. - Highlights: • Chemical modification of the double bonds on an ethene-PMO through the Diels–Alder reaction. • A family of pyrrole derivatives act as dienes in the Diels–Alder reaction. • Well-ordering and mesoporosity are retained after the post-functionalization. • N-containing compounds on the surface of ethene-PMO are present after the Diels–Alder reaction

  1. Fabrication of calix[4]pyrrole nanofilms at the glassy carbon surface and their characterization by spectroscopic, optic and electrochemical methods

    International Nuclear Information System (INIS)

    Taner, Bilge; Ozcan, Emine; Ustuendag, Zafer; Keskin, Selda; Solak, Ali Osman; Eksi, Haslet

    2010-01-01

    meso-Octamethylcalix[4]pyrrole (CP) and meso-heptaethylcalix[4]pyrrole-meso-4-aminophenyl (4APCP) modified glassy carbon (GC) electrodes were prepared by the electrochemical oxidation in acetonitrile solution. Binding of the calix[4]pyrroles with the glassy carbon surface was investigated that it is through the etheric linkage revealed from the reflection-absorption infrared spectroscopy (RAIRS). Surface films of CP and 4APCP were investigated by cyclic voltammetry (CV), ellipsometry, X-ray photoelectron spectroscopy, RAIRS and the contact angle measurements. The thicknesses of the films were determined by ellipsometry which confirmed that the film was multilayer and homogeneous over the surface. Ellipsometric measurements also provided that the CP and 4APCP film thicknesses were 2.49 nm and 4.58 nm for 6 CV cycle modification, corresponding to 66 μF/cm 2 and 106 μF/cm 2 capacitances obtained by CV. The wetting behavior was examined by contact angle measurements and found that the hydrophobicity of the GC-4APCP surface was higher than that of GC-CP, probably due to the aromatic meso substituent present in the former.

  2. Fabrication of calix[4]pyrrole nanofilms at the glassy carbon surface and their characterization by spectroscopic, optic and electrochemical methods

    Energy Technology Data Exchange (ETDEWEB)

    Taner, Bilge; Ozcan, Emine [Selcuk University, Faculty of Science, Dept. of Chemistry, Konya (Turkey); Ustuendag, Zafer [Dumlupinar University, Faculty of Arts and Sciences, Dept. of Chemistry, Kuetahya (Turkey); Keskin, Selda [Middle East Technical University, Central Research Laboratory, Ankara (Turkey); Solak, Ali Osman, E-mail: osolak@science.ankara.edu.t [Ankara University, Faculty of Science, Department of Chemistry, Ankara (Turkey); Eksi, Haslet [Ankara University, Faculty of Science, Department of Chemistry, Ankara (Turkey)

    2010-10-29

    meso-Octamethylcalix[4]pyrrole (CP) and meso-heptaethylcalix[4]pyrrole-meso-4-aminophenyl (4APCP) modified glassy carbon (GC) electrodes were prepared by the electrochemical oxidation in acetonitrile solution. Binding of the calix[4]pyrroles with the glassy carbon surface was investigated that it is through the etheric linkage revealed from the reflection-absorption infrared spectroscopy (RAIRS). Surface films of CP and 4APCP were investigated by cyclic voltammetry (CV), ellipsometry, X-ray photoelectron spectroscopy, RAIRS and the contact angle measurements. The thicknesses of the films were determined by ellipsometry which confirmed that the film was multilayer and homogeneous over the surface. Ellipsometric measurements also provided that the CP and 4APCP film thicknesses were 2.49 nm and 4.58 nm for 6 CV cycle modification, corresponding to 66 {mu}F/cm{sup 2} and 106 {mu}F/cm{sup 2} capacitances obtained by CV. The wetting behavior was examined by contact angle measurements and found that the hydrophobicity of the GC-4APCP surface was higher than that of GC-CP, probably due to the aromatic meso substituent present in the former.

  3. Characterization of electrogenerated polypyrrole-benzophenone films coated on poly(pyrrole-methyl metacrylate) optic-conductive fibers.

    Science.gov (United States)

    Abu-Rabeah, Khalil; Atias, Danit; Herrmann, Sebastien; Frenkel, Julia; Tavor, Dorith; Cosnier, Serge; Marks, Robert S

    2009-09-01

    A conductive surface was created for the development of a biosensing platform via chemical polymerization of pyrrole onto the surface of poly(methyl methacrylate) (PMMA) fibers, with a subsequent electrogeneration of a photoactive linker pyrrole-benzophenone (PyBz) monomer on the fiber surface. Irradiation of the benzophenone groups embedded in the polypyrrole (Ppy) films by UV (350 nm) formed active radicals, allowing covalent attachment of the desired biomaterials. Characterization and optimization of this platform were carried out, with the platform showing conductive, stable, thin, controllable, and light-transmissible film features. Various parameters such as time deposition, process temperature, and activator plus pyrrole monomer concentrations were examined in the study. The morphology and permeability of the optic-fiber PMMA fibers were investigated to examine mass transfer ability. Cyclic voltammetry and amperometry techniques were applied to characterize the electrical features of the surface and charge transfer. The platform potential was then demonstrated by the construction of both amperometric and optical biosensors.

  4. Pyrrole Alkaloids with Potential Cancer Chemopreventive Activity Isolated from a Goji Berry-Contaminated Commercial Sample of African Mango

    Science.gov (United States)

    2015-01-01

    Bioassay-guided fractionation of a commercial sample of African mango (Irvingia gabonensis) that was later shown to be contaminated with goji berry (Lycium sp.) led to the isolation of a new pyrrole alkaloid, methyl 2-[2-formyl-5-(hydroxymethyl)-1H-pyrrol-1-yl]propanoate, 1, along with seven known compounds, 2–8. The structures of the isolated compounds were established by analysis of their spectroscopic data. The new compound 1g showed hydroxyl radical-scavenging activity with an ED50 value of 16.7 μM, whereas 4-[formyl-5-(methoxymethyl)-1H-pyrrol-1-yl]butanoic acid (2) was active in both the hydroxyl radical-scavenging (ED50 11.9 μM) and quinone reductase-induction [CD (concentration required to double QR activity) 2.4 μM)] assays used. The isolated compounds were shown to be absent in a taxonomically authenticated African mango sample but present in three separate authentic samples of goji berry (Lycium barbarum) using LC-MS and 1H NMR fingerprinting analysis, including one sample that previously showed inhibitory activity in vivo in a rat esophageal cancer model induced with N-nitrosomethylbenzylamine. Additionally, microscopic features characteristic of goji berry were observed in the commercial African mango sample. PMID:24792835

  5. Insecticides suppress natural enemies and increase pest damage in cabbage.

    Science.gov (United States)

    Bommarco, Riccardo; Miranda, Freddy; Bylund, Helena; Björkman, Christer

    2011-06-01

    Intensive use of pesticides is common and increasing despite a growing and historically well documented awareness of the costs and hazards. The benefits from pesticides of increased yields from sufficient pest control may be outweighed by developed resistance in pests and killing of beneficial natural enemies. Other negative effects are human health problems and lower prices because of consumers' desire to buy organic products. Few studies have examined these trade-offs in the field. Here, we demonstrate that Nicaraguan cabbage (Brassica spp.) farmers may suffer economically by using insecticides as they get more damage by the main pest diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), at the same time as they spend economic resources on insecticides. Replicated similarly sized cabbage fields cultivated in a standardized manner were either treated with insecticides according common practice or not treated with insecticides over two seasons. Fields treated with insecticides suffered, compared with nontreated fields, equal or, at least in some periods of the seasons, higher diamondback moth pest attacks. These fields also had increased leaf damage on the harvested cabbage heads. Weight and size of the heads were not affected. The farmers received the same price on the local market irrespective of insecticide use. Rates of parasitized diamondback moth were consistently lower in the treated fields. Negative effects of using insecticides against diamondback moth were found for the density of parasitoids and generalist predatory wasps, and tended to affect spiders negatively. The observed increased leaf damages in insecticide-treated fields may be a combined consequence of insecticide resistance in the pest, and of lower predation and parasitization rates from naturally occurring predators that are suppressed by the insecticide applications. The results indicate biological control as a viable and economic alternative pest management strategy

  6. Diagnostic Doses of Insecticides for Adult Aedes aegypti to Assess Insecticide Resistance in Cuba.

    Science.gov (United States)

    Rodríguez, María Magdalena; Crespo, Ariel; Hurtado, Daymi; Fuentes, Ilario; Rey, Jorge; Bisset, Juan Andrés

    2017-06-01

    The objective of this study was to determine diagnostic doses (DDs) of 5 insecticides for the Rockefeller susceptible strain of Aedes aegypti , using the Centers for Disease Control and Prevention (CDC) bottle bioassay as a tool for monitoring insecticide resistance in the Cuban vector control program. The 30-min DD values determined in this study were 13.5 μg/ml, 6.5 μg/ml, 6 μg/ml, 90.0 μg/ml, and 15.0 μg/ml for cypermethrin, deltamethrin, lambda-cyhalothrin, chlorpyrifos, and propoxur, respectively. To compare the reliability of CDC bottle bioassay with the World Health Organization susceptible test, 3 insecticide-resistant strains were evaluated for deltamethrin and lambda-cyhalothrin. Results showed that the bottles can be used effectively from 21 to 25 days after treatment and reused up to 4 times, depending on the storage time. The CDC bottle bioassay is an effective tool to assess insecticide resistance in field populations of Ae. aegypti in Cuba and can be incorporated into vector management programs using the diagnostic doses determined in this study.

  7. A New Series of Pyrrole-Based Chalcones: Synthesis and Evaluation of Antimicrobial Activity, Cytotoxicity, and Genotoxicity

    Directory of Open Access Journals (Sweden)

    Ahmet Özdemir

    2017-11-01

    Full Text Available In an effort to develop new potent antimicrobial and anticancer agents, new pyrrole-based chalcones were designed and synthesized via the base-catalyzed Claisen-Schmidt condensation of 2-acetyl-1-methylpyrrole with 5-(arylfurfural derivatives. The compounds were evaluated for their in vitro antimicrobial effects on pathogenic bacteria and Candida species using microdilution and ATP luminescence microbial cell viability assays. MTT assay was performed to determine the cytotoxic effects of the compounds on A549 human lung adenocarcinoma, HepG2 human hepatocellular carcinoma, C6 rat glioma, and NIH/3T3 mouse embryonic fibroblast cell lines. 1-(1-Methyl-1H-pyrrol-2-yl-3-(5-(4-chlorophenylfuran-2-ylprop-2-en-1-one (7 and 1-(1-methyl-1H-pyrrol-2-yl-3-(5-(2,5-dichlorophenylfuran-2-ylprop-2-en-1-one (9 were found to be the most potent antifungal agents against Candida krusei and therefore these compounds were chosen for flow cytometry analysis and Ames MPF assay. ATP bioluminescence assay indicated that the antifungal activity of compounds 7 and 9 against C. krusei was significantly higher than that of other compounds and the reference drug (ketoconazole, whereas flow cytometry analysis revealed that the percentage of dead cells treated with compound 7 was more than that treated with compound 9 and ketoconazole. According to Ames MPF assay, compounds 7 and 9 were found to be non-genotoxic against TA98 and TA100 with/without metabolic activation. MTT assay indicated that 1-(1-methyl-1H-pyrrol-2-yl-3-(5-(2-nitrophenylfuran-2-ylprop-2-en-1-one (3 showed more selective anticancer activity than cisplatin against the HepG2 cell line. On the other hand, 1-(1-methyl-1H-pyrrol-2-yl-3-(5-(4-nitrophenylfuran-2-ylprop-2-en-1-one (1 was found to be more effective and selective on the A549 cell line than cisplatin.

  8. New 1H-pyrrole-2,5-dione derivatives as efficient organic inhibitors of carbon steel corrosion in hydrochloric acid medium: Electrochemical, XPS and DFT studies

    International Nuclear Information System (INIS)

    Zarrouk, A.; Hammouti, B.; Lakhlifi, T.; Traisnel, M.; Vezin, H.; Bentiss, F.

    2015-01-01

    Highlights: • 1H-pyrrole derivatives act as good corrosion inhibitors for carbon steel in 1 M HCl. • Adsorption of the inhibitors on carbon steel surface obeys Langmuir’s isotherm. • XPS showed that the inhibitors are chemisorbed on the metal surface. • Quantum chemical parameters were correlated with experimental results. - Abstract: New 1H-pyrrole-2,5-dione derivatives, namely 1-phenyl-1H-pyrrole-2,5-dione (PPD) and 1-(4-methylphenyl)-1H-pyrrole-2,5-dione (MPPD) were synthesised and their inhibitive action against the corrosion of carbon steel in 1 M HCl solution were investigated at 308 K by weight loss, potentiodynamic polarization curves, and electrochemical impedance spectroscopy (EIS) methods. The results showed that the investigated 1H-pyrrole-2,5-dione derivatives are good corrosion inhibitors for carbon steel in 1 M HCl medium, their inhibition efficiency increased with inhibitor concentration, and MPPD is slightly more effective than PPD. Potentiostatic polarization study showed that PPD and MPPD are mixed-type inhibitors in 1 M HCl. Impedance experimental data revealed a frequency distribution of the capacitance, simulated as constant phase element. The results obtained from electrochemical and weight loss studies were in reasonable agreement. The adsorption of MPPD and PPD on steel surface obeyed Langmuir’s adsorption isotherm. Thermodynamic data and XPS analysis clearly indicated that the adsorption mechanism of 1H-pyrrole-2,5-dione derivatives on carbon steel surface in 1 M HCl solution is mainly controlled by a chemisorption process. Quantum chemical calculations using the Density Functional Theory (DFT) were performed on 1H-pyrrole-2,5-dione derivatives to determine the relationship between molecular structures and their inhibition efficiencies

  9. Emamectin benzoate: new insecticide against Helicoverpa armigera.

    Science.gov (United States)

    Fanigliulo, A; Sacchetti, M

    2008-01-01

    Emamectin benzoate is a new insecticide of Syngenta Crop Protection, with a new mechanism of action and a strong activity against Lepidoptera as well as with and a high selectivity on useful organisms. This molecule acts if swallowed and has some contact action. It penetrates leaf tissues (translaminar activity) and forms a reservoir within the leaf. The mechanism of action is unique in the panorama of insecticides. In facts, it inhibits muscle contraction, causing a continuous flow of chlorine ions in the GABA and H-Glutamate receptor sites. During 2006 and 2007, experimentation was performed by the Bioagritest test facility, according to EPPO guidelines and Principles of Good Experimental Practice (GEP), aiming at establishing the biological efficacy and the selectivity of Emamectin benzoate on industry tomato against Helicoverpa armigera (Lepidoptera: Noctuidoe). The study was performed in Tursi-Policoro (Matera), southern Italy. Experimental design consisted in random blocks, in 4 repetitions. A dosage of 1.5 Kg/ha of the formulate was compared with two commercial formulates: Spinosad 0.2 kg/ha (Laser, Dow Agrosciences Italia) and Indoxacarb 0.125 kg/ha (Steward EC insecticide, Dupont). Three foliage applications were applied every 8 days. The severity of damage induced by H. armigera was evaluated on fruits. Eventual phytotoxic effects were also evaluated. Climatic conditions were optimal for Lepidoptera development, so that the percentage of fruits attacked in 2007 at the first scouting was 68.28%. Emamectin benzoate has shown, in two years of testing, a high control of H. armigera if compared with the standards Indoxacarb and Spinosad. No effect of phytotoxicity was noticed on fruits.

  10. BACILLUS THURINGIENSIS ELASTASES WITH INSECTICIDE ACTIVITY

    Directory of Open Access Journals (Sweden)

    E. V. Matseliukh

    2015-10-01

    Full Text Available The purpose of the research was a screening of proteases with elastase activity among Bacillus thuringiensis strains, their isolation, partially purification, study of physicochemical properties and insecticide activity in relation to the larvae of the Colorado beetle. The objects of the investigation were 18 strains of B. thuringiensis, isolated from different sources: sea water, dry biological product "Bitoksibatsillin" and also from natural populations of Colorado beetles of the Crimea, Kherson, Odesa, Mykolaiv and Zaporizhiia regions of Ukraine. Purification of enzymes with elastase activity isolated from above mentioned strains was performed by gel-chromatography and insecticide activity was studied on the 3–4 larvae instar of Colorado beetle. The ability of a number of B. thuringiensis strains to synthesize the proteases with elastase activity has been established. The most active were enzymes obtained from strains IMV B-7465, IMV B-7324 isolated from sea water, and strains 9, 902, Bt-H and 0-239 isolated from Colorado beetles. The study of the physicochemical properties of the partially purified proteases of these strains showed that they belonged to enzymes of the serine type. Peptidases of a number of B. thuringiensis strains (IMV B-7324, IMV B-7465, 902, 0-239, 9 are metal-dependent enzymes. Optimal conditions of action of all tested enzymes are the neutral and alkaline рН values and the temperatures of 30–40 °С. The studies of influence of the complex enzyme preparations and partially purified ones of B. thuringiensis strains on the larvae instar of Colorado beetles indicated that enzymes with elastase activity could be responsible for insecticide action of the tested strains.

  11. Toxicity of some insecticides used in maize crop on Trichogramma pretiosum (Hymenoptera, Trichogrammatidae immature stages

    Directory of Open Access Journals (Sweden)

    Jander R Souza

    2014-04-01

    Full Text Available Fall armyworm Spodoptera frugiperda (J.E. Smith, 1797 (Lepidoptera: Noctuidae is an important pest of maize (Zea mays L. crops in Brazil. The effects of beta-cypermethrin, chlorfenapyr, chlorpyrifos, spinosad, etofenprox, triflumuron, alpha-cypermethrin/teflubenzuron, and lambda-cyhalothrin/thiamethoxam on Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae immature stages were evaluated. Eggs of Anagasta kuehniella (Zeller, 1879 (Lepidoptera: Pyralidae, containing immature stages of the parasitoid were dipped in water solution pesticides, to evaluate their effects on emergence and sex ratio of F1 parasitoids. For F2 parasitoids, emergence, parasitism capacity, and sex ratio were evaluated. Beta-cypermethrin, chlorfenapyr, chlorpyrifos, and spinosad affected the emergence success of F1 T. pretiosum. Insects exposed to etofenprox and alpha-cypermethrin/teflubenzuron during the egg-larval period and to lambda-cyhalothrin/thiamethoxam during the pupal stage also suffered reduction in the emergence. Beta-cypermethrin affected the sex ratio of F1 T. pretiosum from host eggs treated during the egg-larval period; spinosad affected it during the egg-larval period and the pupal stage, whereas chlorpyrifos did the same when applied during the pupal stage. Chlorpyrifos also affected the sex ratio of F2 parasitoids, but only when applied during the egg-larval period, whereas chlorfenapyr reduced this trait when applied during the pre-pupal phase. Chlorpyrifos and alpha-cypermethrin/teflubenzuron affected the parasitism capacity of F1 females from eggs treated during the egg-larval period. Considering the overall effects, only etofenprox and triflumuron were selective on T. pretiosum when applied on parasitized A. kuehniella eggs. Further studies need to be carried out to verify the toxicity of the other pesticides under semi-field and field conditions.

  12. Effectiveness and profitability of insecticide formulations used for ...

    African Journals Online (AJOL)

    To identify optimal pest control with lower economic risks to farmers, we investigated the effectiveness and profitability of different insecticides and insecticide formulations against bean fly (Ophiomyia spp.) and bean flower thrips (Megalurothrips sjostedtii). Two separate experiments were conducted during 2009 to 2012.

  13. Effects of insecticide spray application on insect pest infestation and ...

    African Journals Online (AJOL)

    USER

    2010-03-15

    Mar 15, 2010 ... This study provides information on the incidence of major insect pests of cowpea as well as the minimum insecticide control intervention necessary for effectively reducing cowpea yield losses on the field. Two insecticide spray regimes (once at flowering and podding) significantly reduced insect population ...

  14. Effects of insecticide spray application on insect pest infestation and ...

    African Journals Online (AJOL)

    Field studies were conducted during the 2008 - 2009 cropping season to determine the minimal insecticide application which can reduce cowpea yield losses on the field due to insect pest infestations in the Transkei region of South Africa. Treatments consisted of five cowpea varieties and four regimes of insecticide spray ...

  15. Design, Synthesis and Insecticidal Activities of Novel Phenyl Substituted Isoxazolecarboxamides

    Institute of Scientific and Technical Information of China (English)

    LIU Peng-fei; ZHANG Ji-feng; YAN Tao; XIONG Li-xia; LI Zheng-ming

    2012-01-01

    Thirteen novel phenyl substituted isoxazolecarboxamides were synthesized,and their structures were characterized by 1H NMR,elementary analysis and high-resolution mass spectrometry(HRMS) techniques.Their evaluated insecticidal activities against oriental armyworm(Mythimna separata) indicate that the phcnyl substituted isoxazolecarboxamides exhibited moderate insecticidal activities,among which compounds 9c and 9k showed comparatively higher activities.

  16. Mechanistic modeling of insecticide risks to breeding birds in ...

    Science.gov (United States)

    Insecticide usage in the United States is ubiquitous in urban, suburban, and rural environments. In evaluating data for an insecticide registration application and for registration review, scientists at the United States Environmental Protection Agency (USEPA) assess the fate of the insecticide and the risk the insecticide poses to the environment and non-target wildlife. At the present time, current USEPA risk assessments do not include population-level endpoints. In this paper, we present a new mechanistic model, which allows risk assessors to estimate the effects of insecticide exposure on the survival and seasonal productivity of birds known to use agricultural fields during their breeding season. The new model was created from two existing USEPA avian risk assessment models, the Terrestrial Investigation Model (TIM v.3.0) and the Markov Chain Nest Productivity model (MCnest). The integrated TIM/MCnest model has been applied to assess the relative risk of 12 insecticides used to control corn pests on a suite of 31 avian species known to use cornfields in midwestern agroecosystems. The 12 insecticides that were assessed in this study are all used to treat major pests of corn (corn root worm borer, cutworm, and armyworm). After running the integrated TIM/MCnest model, we found extensive differences in risk to birds among insecticides, with chlorpyrifos and malathion (organophosphates) generally posing the greatest risk, and bifenthrin and ë-cyhalothrin (

  17. Expression of melanin and insecticidal protein from Rhodotorula ...

    African Journals Online (AJOL)

    Both the salmon/red melanin and the insecticidal producing genes of Rhodotorula glutinis was successfully expressed in Escherichia coli using plasmid pZErO-1. This work suggests that in Rhodotorula species melanin and insecticidal toxin are co-expressed and therefore possibly co-evolved. Keywords: Rhodotorula ...

  18. Guide to testing insecticides on coniferous forest defoliators

    Science.gov (United States)

    Carroll B Jr. Williams; David A. Sharpnack; Liz Maxwell; Patrick J. Shea; Mark D. McGregor

    1985-01-01

    This report provides a guide to techniques for designing field tests of candidate insecticides, and for carrying out pilot tests and control projects. It describes experimental designs for testing hypotheses, and for sampling trees to estimate insect population densities and percent reduction after treatments. Directions for applying insecticides by aircraft and for...

  19. Biological efficacy of the ecotoxically favourable insecticides and ...

    African Journals Online (AJOL)

    Administrator

    2011-05-30

    May 30, 2011 ... different, studies done in natural conditions should be favored. Key words: Insecticides ... insecticide was applied on synthetic or natural food of the target insect ..... Pozsgay M, Fast P, Kaplan H, Carey PR (1987). The effect of ...

  20. Ecdysone Agonist: New Insecticides with Novel Mode of Action

    Directory of Open Access Journals (Sweden)

    Y. Andi Trisyono

    2002-12-01

    Full Text Available Development of insect resistance to insecticide has been the major driving force for the development of new insecticides. Awareness and demand from public for more environmentally friendly insecticides have contributed in shifting the trend from using broad spectrum to selective insecticides. As a result, scientists have looked for new target sites beyond the nervous system. Insect growth regulators (IGRs are more selective insecticides than conventional insecticides, and ecdysone agonists are the newest IGRs being commercialized, e.g. tebufenozide, methoxyfenozide, and halofenozide. Ecdysone agonists bind to the ecdysteroid receptors, and they act similarly to the molting hormone 20-hydroxyecdysone. The binding provides larvae or nymphs with a signal to enter a premature and lethal molting cycle. In addition, the ecdysone agonists cause a reduction in the number of eggs laid by female insects. The ecdysone agonists are being developed as selective biorational insecticides. Tebufenozide and methoxyfenozide are used to control lepidopteran insect pests, whereas halofenozide is being used to control coleopteran insect pests. Their selectivity is due to differences in the binding affinity between these compounds to the receptors in insects from different orders. The selectivity of these compounds makes them candidates to be used in combinations with other control strategies to develop integrated pest management programs in agricultural ecosystems. Key words: new insecticides, selectivity, ecdysone agonists

  1. Identification and cloning of two insecticidal protein genes from ...

    African Journals Online (AJOL)

    Bacillus thuringiensis (Bt) is the most widely applied type of microbial pesticide due to its high specificity and environmental safety. The activity of Bt is largely attributed to the insecticidal crystal protein encoded by the cry genes. Different insecticidal crystal proteins of Bt have different bioactivity against distinct agricultural ...

  2. Interactions of transgenic Bacillus thuringiensis insecticidal crops with spiders (Araneae)

    Science.gov (United States)

    Genetically modified crops expressing insecticidal proteins from Bacillus thuringiensis (Bt) have dramatically increased in acreage since their introduction in the mid-1990’s. Although the insecticidal mechanisms of Bt target specific pests, concerns persist regarding direct and indirect effects on...

  3. Conifer flavonoid compounds inhibit detoxification enzymes and synergize insecticides.

    Science.gov (United States)

    Wang, Zhiling; Zhao, Zhong; Cheng, Xiaofei; Liu, Suqi; Wei, Qin; Scott, Ian M

    2016-02-01

    Detoxification by glutathione S-transferases (GSTs) and esterases are important mechanisms associated with insecticide resistance. Discovery of novel GST and esterase inhibitors from phytochemicals could provide potential new insecticide synergists. Conifer tree species contain flavonoids, such as taxifolin, that inhibit in vitro GST activity. The objectives were to test the relative effectiveness of taxifolin as an enzyme inhibitor and as an insecticide synergist in combination with the organophosphorous insecticide, Guthion (50% azinphos-methyl), and the botanical insecticide, pyrethrum, using an insecticide-resistant Colorado potato beetle (CPB) Leptinotarsa decemlineata (Say) strain. Both taxifolin and its isomer, quercetin, increased the mortality of 1(st) instar CPB larvae after 48h when combined with Guthion, but not pyrethrum. Taxifolin had greater in vitro esterase inhibition compared with the commonly used esterase inhibitor, S, S, S-tributyl phosphorotrithioate (DEF). An in vivo esterase and GST inhibition effect after ingestion of taxifolin was measured, however DEF caused a greater suppression of esterase activity. This study demonstrated that flavonoid compounds have both in vitro and in vivo esterase inhibition, which is likely responsible for the insecticide synergism observed in insecticide-resistant CPB. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  4. Calix[2]pyreno[2]pyrrole as a Fluorescence Chemical Probe for Polynitroaromatics

    International Nuclear Information System (INIS)

    Park, Kyung Hwa; Yoo, Jae Duk; Lee, Chang Hee; Ka, Jae Won

    2012-01-01

    We have demonstrated that the new, readily synthesized and well characterized calix pyreno pyrrole fluorescence molecular probe can detect polynitroaromatic compounds with high affinity. In addition, this highly fluorescent neutral molecular receptor also exhibits enhanced binding affinity towards TNT which is associated with the formation of a pi-complex. The dynamic nature of the current system may enable it to serve as an excellent scaffold for electron-deficient guest molecular binding. Studies for other neutral molecules including metal ions are under in active progress. The elevated selectivity and sensitivity for specific analytes are the core requirements for an ideal chemical probes. A signal induced by guest binding must be sensitive enough so that accurate real time monitoring could be satisfactorily achieved. Introduction of signaling units at suitable places in which they can directly interact with the recognition events is critical in designing chemosensors. Among various signaling events, fluorescence changes are often applied for the sensitive detection of various analytes. An easy modulation of the photochemical properties of the signaling units is an additional advantage in compatibility and applications. Chemosensors for the detection of explosives becomes important due to their immediate applications in remedation of explosive manufacturing sites, homeland security or forensic sciences. With that in mind, numerous methods for the explosive detection have been reported in recent years. Nevertheless, some detection methods sometimes require sophisticated instrumentation which is not easy for on-site testing

  5. Lack of effect of deferoxamine, dimethyl sulfoxide, and catalase on monocrotaline pyrrole pulmonary injury

    International Nuclear Information System (INIS)

    Bruner, L.H.; Johnson, K.; Carpenter, L.J.; Roth, R.A.

    1987-01-01

    Monocrotaline pyrrole (MCTP) is a reactive metabolite of the pyrrolizidine alkaloid monocrotaline. MCTP given intravenously to rats causes pulmonary hypertension and right ventricular hypertrophy. Lesions in lungs after MCTP treatment contain macrophages and neutrophils, which may contribute to the damage by generation of reactive oxygen metabolites. Rats were treated with MCTP and agents known to protect against oxygen radical-mediated damage in acute models of neutrophil-dependent lung injury. Rats received MCTP and deferoxamine mesylate (DF), dimethyl sulfoxide (DMSO), or polyethylene glycol-coupled catalase (PEG-CAT). MCTP/vehicle-treated controls developed lung injury manifested as increased lung weight, release of lactate dehydrogenase into the airway, and sequestration of 125 I-labeled bovine serum albumin in the lungs. Cotreatment of rats with DF, DMSO, or PEG-CAT did not protect against the injury due to MCTP. These results suggest that toxic oxygen metabolites do not play an important role in the pathogenesis of MCTP-induced pulmonary injury

  6. Botanical insecticides inspired by plant-herbivore chemical interactions.

    Science.gov (United States)

    Miresmailli, Saber; Isman, Murray B

    2014-01-01

    Plants have evolved a plethora of secondary chemicals to protect themselves against herbivores and pathogens, some of which have been used historically for pest management. The extraction methods used by industry render many phytochemicals ineffective as insecticides despite their bioactivity in the natural context. In this review, we examine how plants use their secondary chemicals in nature and compare this with how they are used as insecticides to understand why the efficacy of botanical insecticides can be so variable. If the commercial production of botanical insecticides is to become a viable pest management option, factors such as production cost, resource availability, and extraction and formulation techniques need be considered alongside innovative application technologies to ensure consistent efficacy of botanical insecticides. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. An Operational Framework for Insecticide Resistance Management Planning.

    Science.gov (United States)

    Chanda, Emmanuel; Thomsen, Edward K; Musapa, Mulenga; Kamuliwo, Mulakwa; Brogdon, William G; Norris, Douglas E; Masaninga, Freddie; Wirtz, Robert; Sikaala, Chadwick H; Muleba, Mbanga; Craig, Allen; Govere, John M; Ranson, Hilary; Hemingway, Janet; Seyoum, Aklilu; Macdonald, Michael B; Coleman, Michael

    2016-05-01

    Arthropod vectors transmit organisms that cause many emerging and reemerging diseases, and their control is reliant mainly on the use of chemical insecticides. Only a few classes of insecticides are available for public health use, and the increased spread of insecticide resistance is a major threat to sustainable disease control. The primary strategy for mitigating the detrimental effects of insecticide resistance is the development of an insecticide resistance management plan. However, few examples exist to show how to implement such plans programmatically. We describe the formulation and implementation of a resistance management plan for mosquito vectors of human disease in Zambia. We also discuss challenges, steps taken to address the challenges, and directions for the future.

  8. Formation process of silver-polypyrrole coaxial nanocables synthesized by redox reaction between AgNO3 and pyrrole in the presence of poly(vinylpyrrolidone).

    Science.gov (United States)

    Chen, Aihua; Kamata, Kaori; Nakagawa, Masaru; Iyoda, Tomokazu; Haiqiao Wang, Haiqiao; Li, Xiaoyu

    2005-10-06

    We have recently demonstrated a one-step process to fabricate silver-polypyrrole (PPy) coaxial nanocables (Chen, A.; Wang, H.; Li, X. Chem. Commun. 2005, 14, 1863). The formation process of silver-PPy coaxial nanocables is discussed in this article. It was found from the results of TEM and SEM images that large numbers of silver atoms were formed when AgNO3 was added to a pyrrole solution. Then silver atoms transform to silver-PPy nanosheets with regular morphology, which will connect together to be more stable. Silver-PPy nanocables will be able to grow at the expense of the silver-PPy nanosheets. Poly(vinylpyrrolidone) (PVP) plays crucial roles in this process: as a capping agent to form silver nanowires, and as a dispersant of pyrrole monomers, which can influence the site at which pyrrole monomer exists. On the basis of experimental analysis, the possible mechanism was proposed. Because of the effect of PVP, silver ions and pyrrole monomers are apt to be adsorbed at the [111] and [100] facets of silver nanosheets, respectively. Obvious polymerization will take place on the boundary of the [111] and [100] facets. The PPy layer stays stable on the [100] facets. Meanwhile, newly formed silver atoms and silver nanosheets will further ripen and grow on the [111] facets. In a word, the morphology of final products and the formation process are determined by the reaction site between AgNO3 and the pyrrole monomer, which is influenced by PVP.

  9. Zinc hexacyanoferrate film as an effective protecting layer in two-step and one-step electropolymerization of pyrrole on zinc substrate

    International Nuclear Information System (INIS)

    Pournaghi-Azar, M.H.; Nahalparvari, H.

    2005-01-01

    The two-step and one-step electrosynthesis processes of polypyrrole (PPy) films on the zinc substrate are described. The two-step process includes (i) the zinc surface pretreatment with hexacyanoferrate ion in the aqueous medium in order to form a zinc hexacyanoferrate (ZnHCF) film non-blocking passive layer on the surface and with the view to prevent its reactivity and (ii) electropolymerization of pyrrole on the ZnHCF vertical bar Zn-modified electrode in aqueous pyrrole solution. In this context, both the non-electrolytic and electrolytic procedures were adapted, and the effect of some experimental conditions such as supporting electrolyte, pH and temperature of the solution at the zinc surface pretreatment step as well as pyrrole concentration and electrochemical techniques at the polymerization step was investigated. By optimizing the experimental conditions in both steps, we have obtained a homogeneous and strongly adherent PPy films on the zinc substrate. The one-step process is based on the use of an aqueous medium containing Fe(CN) 6 4- and pyrrole. The ferrocyanide ion passivates the substrate by formation of ZnHCF film during the electropolymerization process of pyrrole and therefore makes it possible to obtain strongly adherent PPy films, with controlled thickness, either by cyclic voltammetry or by electrolysis at constant current or constant potential without any previously treatment of the zinc electrode surface. The polypyrrole films deposited on the zinc electrode were characterized by cyclic voltammetry and scanning electron microscopic (SEM) measurement

  10. Rice Production without Insecticide in Smallholder Farmer's Field

    Directory of Open Access Journals (Sweden)

    M. P. Ali

    2017-05-01

    Full Text Available Highlights:Use of perching, sweeping, and need based insecticide (IPM technique useage produce at par yields compared to prophylactic insecticide useage in rice fields.There exists a technique that can reduce 75% of insecticide useage in rice field.The results were obtained in cooperation between smallholder rice farmers and researchers of Bangladesh.Currently rice protection from insect pests solely depends on chemical pesticides which have tremendous impact on biodiversity, environment, animal, and human health. To reduce their impact from our society we need to cut pesticide use from agricultural practices. To address this issue, we did an experiment to identify realistic solutions that could help farmers build sustainable crop protection systems and minimize useage of insecticides and thus reduce the impact of pesticides in the environment. Innovations developed jointly by farmers and researchers and evaluated for their potential to be adopted by more farmers. In this paper we tested four management practices jointly with smallholder farmer fields in order to select the best one. Four management practices were used namely, T1 = Prophylactic use of insecticide where insecticide was applied in rice field at every 15 days interval without judging the infestation level; T2 = Perching (that is, placing roosting (perching sites for insectivorous birds within the rice field and concurrent sweep net samples along with need-based insecticide application; T3 = Perching only; and T4 = Farmer's own practices. The results revealed that routine application of insecticides for crop protection is not mandatory which is commonly found at use in rice farmers. In our experiment, where prophylactic method or farmers used 3–4 times insecticides without judging the insect pests infestation level, the similar pest population was found when compared to the field where insecticide was not applied. Our management system reduced by 75% the use of insecticides even

  11. Construction of a monoanionic S,N,S-pincer ligand with a pyrrole core by sequential [1,2] phospho-Fries rearrangement. Characterization of palladium and silver coordination complexes

    NARCIS (Netherlands)

    Fraix, A.; Lutz, M.; Spek, A.L.; Klein Gebbink, R.J.M.; van Koten, G.; Salaun, J. -Y; Jaffrès, P. -A

    2010-01-01

    The synthesis of an S,NH,S-pincer ligand possessing a pyrrole core and two O,O-diethylthiophosphonyl groups to design PS lateral coordination sites is reported. The synthetic procedure to produce this ligand makes use of the nitrogen atom of the pyrrole heterocycle to successively functionalize the

  12. Insecticide-induced hormesis and arthropod pest management.

    Science.gov (United States)

    Guedes, Raul Narciso C; Cutler, G Christopher

    2014-05-01

    Ecological backlashes such as insecticide resistance, resurgence and secondary pest outbreaks are frequent problems associated with insecticide use against arthropod pest species. The last two have been particularly important in sparking interest in the phenomenon of insecticide-induced hormesis within entomology and acarology. Hormesis describes a biphasic dose-response relationship that is characterized by a reversal of response between low and high doses of a stressor (e.g. insecticides). Although the concept of insecticide-induced hormesis often does not receive sufficient attention, or has been subject to semantic confusion, it has been reported in many arthropod pest species and natural enemies, and has been linked to pest outbreaks and potential problems with insecticide resistance. The study of hormesis remains largely neglected in entomology and acarology. Here, we examined the concept of insecticide-induced hormesis in arthropods, its functional basis and potential fitness consequences, and its importance in arthropod pest management and other areas. © 2013 Society of Chemical Industry.

  13. Electrografting of in situ generated pyrrole derivative diazonium salt for the surface modification of nickel

    International Nuclear Information System (INIS)

    Jacques, A.; Devillers, S.; Delhalle, J.; Mekhalif, Z.

    2013-01-01

    Highlights: • Electrografting of in situ generated 4-pyrrolylphenyldiazonium (Py-PD) on Ni. • Generation of Py-PD from 4-pyrrolylaniline in 3 acidic conditions followed by UV. • XPS and SEM confirm efficiency, reproducibility and homogeneity of the grafting. • Electrografting process assessed by CV. • Barrier properties of the grafted film evidenced by CV. -- Abstract: This work reports for the first time on the modification of nickel surfaces by cathodic electrografting of in situ generated diazonium. An original diazonium salt (the 4-pyrrolylphenyldiazonium called Py-PD hereafter) was electrografted on nickel after its generation from 4-(1H-pyrrol-1-yl)aniline (Py-A) in presence of three acidic conditions (1, 2 and 10 equiv. of HClO 4 /Py-A) has been investigated by UV–vis spectroscopy. Results show that the potentiostatic electrografting of Py-PD is concomitant with nickel and proton reduction. This electrografting leads to the formation of multilayered films in each of the studied in situ generation conditions. The use of 1 equiv. of HClO 4 /Py-A for the in situ generation results in the formation of inhomogeneous and irreproducible coatings while 2 and 10 equiv. lead to the formation of highly covering, homogeneous and reproducible films. These films present good electrochemical barrier properties toward the ferri/ferrocyanide couple. The use of gentle stoichiometric acidic conditions for in situ diazonium generation widens the application field of this one-step procedure to the surface modification of oxidizable materials presenting an unstable oxide layer

  14. Excess L-arginine restores endothelium-dependent relaxation impaired by monocrotaline pyrrole

    International Nuclear Information System (INIS)

    Cheng Wei; Oike, Masahiro; Hirakawa, Masakazu; Ohnaka, Keizo; Koyama, Tetsuya; Ito, Yushi

    2005-01-01

    The pyrrolizidine alkaloid plant toxin monocrotaline pyrrole (MCTP) causes pulmonary hypertension in experimental animals. The present study aimed to examine the effects of MCTP on the endothelium-dependent relaxation. We constructed an in vitro disease model of pulmonary hypertension by overlaying MCTP-treated bovine pulmonary artery endothelial cells (CPAEs) onto pulmonary artery smooth muscle cell-embedded collagen gel lattice. Acetylcholine (Ach) induced a relaxation of the control CPAEs-overlaid gels that were pre-contracted with noradrenaline, and the relaxation was inhibited by L-NAME, an inhibitor of NO synthase (NOS). In contrast, when MCTP-treated CPAEs were overlaid, the pre-contracted gels did not show a relaxation in response to Ach in the presence of 0.5 mM L-arginine. Expression of endothelial NOS protein, Ach-induced Ca 2+ transients and cellular uptake of L-[ 3 H]arginine were significantly smaller in MCTP-treated CPAEs than in control cells, indicating that these changes were responsible for the impaired NO production in MCTP-treated CPAEs. Since cellular uptake of L-[ 3 H]arginine linearly increased according to its extracellular concentration, we hypothesized that the excess concentration of extracellular L-arginine might restore NO production in MCTP-treated CPAEs. As expected, in the presence of 10 mM L-arginine, Ach showed a relaxation of the MCTP-treated CPAEs-overlaid gels. These results indicate that the impaired NO production in damaged endothelial cells can be reversed by supplying excess L-arginine

  15. Transition metal doped poly(aniline-co-pyrrole)/multi-walled carbon nanotubes nanocomposite for high performance supercapacitor electrode materials

    International Nuclear Information System (INIS)

    Dhibar, Saptarshi; Bhattacharya, Pallab; Hatui, Goutam; Das, C.K.

    2015-01-01

    Highlights: • The CuCl 2 doped copolymer (PANI and PPy)/MWCNTs nanocomposite was prepared. • The nanocomposite achieved highest specific capacitance of 383 F/g at a 0.5 A/g. • Nanocomposite exhibits better energy density as well as power density. • The nanocomposite also showed better electrical conductivity at room temperature. • The nanocomposite can be used as promising electrode materials for supercapacitor. - Abstract: In this present communication, copolymer of polyaniline (PANI) and polypyrrole (PPy) that is poly(aniline-co-pyrrole) [poly(An-co-Py)], copper chloride (CuCl 2 ) doped poly(aniline-co-pyrrole) [poly(An-co-Py) Cu], and CuCl 2 doped poly(aniline-co-pyrrole)/multi walled carbon nanotubes (MWCNTs) [poly(An-co-Py) Cu CNT] nanocomposite have been prepared by a simple and inexpensive in-situ chemical oxidative polymerization method, using ammonium persulfate (APS) as oxidant and hydrochloric acid (HCl) as dopant and investigated as high performance supercapacitor electrode materials. The possible interaction between CuCl 2 with copolymers and MWCNTs was investigated by Fourier transform infrared spectroscopy (FTIR) and UV–visible spectroscopy analysis. The morphological characteristic of all the electrode materials were analyzed by Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) study. The electrochemical characterizations of all the electrode materials were carried out by three electrode probe method where, standard calomel electrode and platinum were used as reference and counter electrodes, respectively. Among all the electrode materials, poly(An-co-Py) Cu CNT nanocomposite achieved highest specific capacitance value of 383 F/g at 0.5 A/g scan rate. The nanocomposite showed better electrical conductivity at room temperature and also attained nonlinear current–voltage characteristic. Based on the superior electrochemical as well as other properties the as prepared nanocomposite can be used

  16. Transition metal doped poly(aniline-co-pyrrole)/multi-walled carbon nanotubes nanocomposite for high performance supercapacitor electrode materials

    Energy Technology Data Exchange (ETDEWEB)

    Dhibar, Saptarshi; Bhattacharya, Pallab; Hatui, Goutam; Das, C.K., E-mail: chapal12@yahoo.co.in

    2015-03-15

    Highlights: • The CuCl{sub 2} doped copolymer (PANI and PPy)/MWCNTs nanocomposite was prepared. • The nanocomposite achieved highest specific capacitance of 383 F/g at a 0.5 A/g. • Nanocomposite exhibits better energy density as well as power density. • The nanocomposite also showed better electrical conductivity at room temperature. • The nanocomposite can be used as promising electrode materials for supercapacitor. - Abstract: In this present communication, copolymer of polyaniline (PANI) and polypyrrole (PPy) that is poly(aniline-co-pyrrole) [poly(An-co-Py)], copper chloride (CuCl{sub 2}) doped poly(aniline-co-pyrrole) [poly(An-co-Py) Cu], and CuCl{sub 2} doped poly(aniline-co-pyrrole)/multi walled carbon nanotubes (MWCNTs) [poly(An-co-Py) Cu CNT] nanocomposite have been prepared by a simple and inexpensive in-situ chemical oxidative polymerization method, using ammonium persulfate (APS) as oxidant and hydrochloric acid (HCl) as dopant and investigated as high performance supercapacitor electrode materials. The possible interaction between CuCl{sub 2} with copolymers and MWCNTs was investigated by Fourier transform infrared spectroscopy (FTIR) and UV–visible spectroscopy analysis. The morphological characteristic of all the electrode materials were analyzed by Field emission scanning electron microscopy (FESEM) and Transmission electron microscopy (TEM) study. The electrochemical characterizations of all the electrode materials were carried out by three electrode probe method where, standard calomel electrode and platinum were used as reference and counter electrodes, respectively. Among all the electrode materials, poly(An-co-Py) Cu CNT nanocomposite achieved highest specific capacitance value of 383 F/g at 0.5 A/g scan rate. The nanocomposite showed better electrical conductivity at room temperature and also attained nonlinear current–voltage characteristic. Based on the superior electrochemical as well as other properties the as prepared

  17. Synthesis and electrochemical properties of novel, donor–acceptor pyrrole derivatives with 1,8-naphthalimide units and their polymers

    International Nuclear Information System (INIS)

    Ledwon, Przemyslaw; Brzeczek, Alina; Pluczyk, Sandra; Jarosz, Tomasz; Kuznik, Wojciech; Walczak, Krzysztof; Lapkowski, Mieczyslaw

    2014-01-01

    A new class of bipolar monomers with pyrrole or thiophene–pyrrole–thiophene as electron donor and 1,8-naphthalimide as electron acceptor unit is reported. Donor–acceptor conjugated polymers were generated electrochemically. The synthesis of monomers, optical, electrochemical and spectroelectrochemical properties supported by theoretical calculations are presented. 1,8-naphthalimide units were attached directly to pyrrole in compounds 1a and 2a or by different bridges in the case of 1b and 2b. Intra-molecular donor–acceptor interactions of the monomers and its polymers were investigated using cyclic voltammetry, in-situ UV–Vis-NIR, electron spin resonance (ESR) spectroelectrochemistry and fluorescence spectroscopy. Studied compounds present large discrepancy (up to 1.31 eV for 2a) between energy gap values determined through electrochemical and optical measurements. The Time-dependent density functional theory (TDDFT) calculations help to explain this discrepancy. This is caused by weak HOMO to LUMO transition, 2000 times weaker than HOMO −2 to LUMO or HOMO to LUMO +1 transition. Altering the structure of monomers yields different stability and properties of obtained polymers. The p- and n-doping processes are separated. Anions are localized mainly on 1,8-naphthalimide units. Cations are localized mainly on pyrrole or thiophene–pyrrole–thiophene moiety and their polymer chains. Attachment of the additional thiophene units decreases the oxidation potential of the monomer and reduces the influence of the steric hindrance between 1,8-naphthalimide moiety and polymer/oligomers chain. This new class of model compounds is promising for use as a material with enhanced charge separation for wide range of optoelectronic, electrochromic and photovoltaic applications

  18. Induced tolerance from a sublethal insecticide leads to cross-tolerance to other insecticides.

    Science.gov (United States)

    Hua, Jessica; Jones, Devin K; Relyea, Rick A

    2014-04-01

    As global pesticide use increases, the ability to rapidly respond to pesticides by increasing tolerance has important implications for the persistence of nontarget organisms. A recent study of larval amphibians discovered that increased tolerance can be induced by an early exposure to low concentrations of a pesticide. Since natural systems are often exposed to a variety of pesticides that vary in mode of action, we need to know whether the induction of increased tolerance to one pesticide confers increased tolerance to other pesticides. Using larval wood frogs (Lithobates sylvaticus), we investigated whether induction of increased tolerance to the insecticide carbaryl (AChE-inhibitor) can induce increased tolerance to other insecticides that have the same mode of action (chlorpyrifos, malathion) or a different mode of action (Na(+)channel-interfering insecticides; permethrin, cypermethrin). We found that embryonic exposure to sublethal concentrations of carbaryl induced higher tolerance to carbaryl and increased cross-tolerance to malathion and cypermethrin but not to chlorpyrifos or permethrin. In one case, the embryonic exposure to carbaryl induced tolerance in a nonlinear pattern (hormesis). These results demonstrate that that the newly discovered phenomenon of induced tolerance also provides induced cross-tolerance that is not restricted to pesticides with the same mode of action.

  19. Quantitative structure-activity relationship (QSAR) for insecticides: development of predictive in vivo insecticide activity models.

    Science.gov (United States)

    Naik, P K; Singh, T; Singh, H

    2009-07-01

    Quantitative structure-activity relationship (QSAR) analyses were performed independently on data sets belonging to two groups of insecticides, namely the organophosphates and carbamates. Several types of descriptors including topological, spatial, thermodynamic, information content, lead likeness and E-state indices were used to derive quantitative relationships between insecticide activities and structural properties of chemicals. A systematic search approach based on missing value, zero value, simple correlation and multi-collinearity tests as well as the use of a genetic algorithm allowed the optimal selection of the descriptors used to generate the models. The QSAR models developed for both organophosphate and carbamate groups revealed good predictability with r(2) values of 0.949 and 0.838 as well as [image omitted] values of 0.890 and 0.765, respectively. In addition, a linear correlation was observed between the predicted and experimental LD(50) values for the test set data with r(2) of 0.871 and 0.788 for both the organophosphate and carbamate groups, indicating that the prediction accuracy of the QSAR models was acceptable. The models were also tested successfully from external validation criteria. QSAR models developed in this study should help further design of novel potent insecticides.

  20. Control of charge transfer by conformational and electronic effects: Donor-donor and donor-acceptor phenyl pyrroles

    International Nuclear Information System (INIS)

    Neubauer, Antje; Bendig, Juergen; Rettig, Wolfgang

    2009-01-01

    Derivatives of N-pyrrolobenzene with a para-donor and a para-acceptor substituent on the benzene ring are compared. It is shown that by a suitable increase of the donor strength of the pyrrolo group, CT fluorescence can be achieved even for donor-donor-substituted benzenes. The ICT emission for sterically hindered compounds is more forbidden than that of unhindered phenyl pyrroles. This suggests conformational effects which induce a narrower twist angle distribution around a perpendicular minimum in the excited state.

  1. Fragmentation dynamics of size selected pyrrole clusters prepared by electron impact ionization: Forming a solvated dimer ion core

    Czech Academy of Sciences Publication Activity Database

    Profant, V.; Poterya, Viktoriya; Fárník, Michal; Slavíček, P.; Buck, U.

    2007-01-01

    Roč. 111, č. 49 (2007), s. 12477-12486 ISSN 1089-5639 R&D Projects: GA AV ČR KAN400400651; GA ČR GA203/06/1290 Grant - others:GA ČR GP203/07/P449; University Grant(CZ) 8113-10/257852 Institutional research plan: CEZ:AV0Z40400503 Source of funding: V - iné verejné zdroje Keywords : pyrrole cluster s * structure * dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.918, year: 2007

  2. Rhodium enalcarbenoids: direct synthesis of indoles by rhodium(II)-catalyzed [4+2] benzannulation of pyrroles.

    Science.gov (United States)

    Dawande, Sudam Ganpat; Kanchupalli, Vinaykumar; Kalepu, Jagadeesh; Chennamsetti, Haribabu; Lad, Bapurao Sudam; Katukojvala, Sreenivas

    2014-04-14

    Disclosed herein is the design of an unprecedented electrophilic rhodium enalcarbenoid which results from rhodium(II)-catalyzed decomposition of a new class of enaldiazo compounds. The synthetic utility of these enalcarbenoids has been successfully demonstrated in the first transition-metal-catalyzed [4+2] benzannulation of pyrroles, thus leading to substituted indoles. The new benzannulation has been applied to the efficient synthesis of the natural product leiocarpone as well as a potent adipocyte fatty-acid binding protein inhibitor. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Quadrupolar, emission-tunable pi-expanded 1,4-dihydropyrrolo 3,2-b pyrroles - synthesis and optical properties

    DEFF Research Database (Denmark)

    Janiga, A.; Bednarska, D.; Thorsted, B.

    2014-01-01

    elucidated by comparison with simpler tetraaryl-analogues. The strong charge-transfer characteristic of these functional dyes can be illustrated by large Stokes shifts (4100-7100 cm(-1)) for A-D-A architectures. The replacement of phenyl rings at positions 2 and 5 with the arylethynylaryl substituents......The synthesis and optical characterization of six novel heteroaromatic-based chromophores is described. The new dyes present mostly an A-D-A general framework, where A is an electron-deficient aromatic ring and D is an electron-rich pyrrolo[3,2-b] pyrrole moiety, linked via triple bonds...

  4. Insecticidal defenses of Piperaceae from the neotropics.

    Science.gov (United States)

    Bernard, C B; Krishanmurty, H G; Chauret, D; Durst, T; Philogène, B J; Sánchez-Vindas, P; Hasbun, C; Poveda, L; San Román, L; Arnason, J T

    1995-06-01

    Insecticidal and growth-reducing properties of extracts of 14 species of American neotropical Piperaceae were investigated by inclusion in diets of a polyphagous lepidopteran, the European corn borer,Ostrinia nubilalis. Nutritional indices suggested most extracts acted by postdigestive toxicity.Piper aduncum, P. tuberculatum, andP. decurrens were among the most active species and were subjected to bioassay-guided isolation of the active components. Dillapiol was isolated from the active fraction ofP. aduncum, piperlonguminine was isolated fromP. tuberculatum, and a novel neolignan fromP. decurrens. The results support other studies on Asian and AfricanPiper species, which suggest that lignans and isobutyl amides are the active defence compounds in this family.

  5. Insecticidal Constituents from Buddlej aalbiflora Hemsl.

    Science.gov (United States)

    Zhang, Xiu-Yun; Shen, Jing; Zhou, Yu; Wei, Zhi-Ping; Gao, Jin-Ming

    2017-06-01

    Eleven known compounds, deoxymikanolide (1), 1,3-dihydroxyxanthone (2), kumatakenin (3), apigenin (4), chrysin (5), kaempferol (6), Iso-kaempferol (7), luteolin (8), luteolin-3',4'-dimethylether-7-O-β-glucoside (9), luteolin-7-O-β-glucoside (10) and quercetin (11) were identified in MeOH extract of Buddleja albiflora Hemsl (Oleaceae). These compounds (each, 1, 0.5 and 0.25 mg mL -1 ) were tested for insecticidal activity against 3rd and 4th-instar larvae of Plutella xylostella, 3rd-instar larvae of Mythimna separata and 3rd-instar larvae of Macrosiphoniella sanborni. The lowest 50% anti-feedant concentration (AFC 50 ) against P. xylostella and 50% lethal concentration (LC 50 ) against P. xylostella and M. sanborni were observed as 0.0058, 0.0046 and 3.4048 mg L -1 , respectively.

  6. Insecticidal Activity of Cyanohydrin and Monoterpenoid Compounds

    Directory of Open Access Journals (Sweden)

    Joel R. Coats

    2000-04-01

    Full Text Available The insecticidal activities of several cyanohydrins, cyanohydrin esters and monoterpenoid esters (including three monoterpenoid esters of a cyanohydrin were evaluated. Topical toxicity to Musca domestica L. adults was examined, and testing of many compounds at 100 mg/fly resulted in 100% mortality. Topical LD50 values of four compounds for M. domestica were calculated. Testing of many of the reported compounds to brine shrimp (Artemia franciscana Kellog resulted in 100% mortality at 10 ppm, and two compounds caused 100% mortality at 1 ppm. Aquatic LC50 values were calculated for five compounds for larvae of the yellow fever mosquito (Aedes aegypti (L.. Monoterpenoid esters were among the most toxic compounds tested in topical and aquatic bioassays.

  7. Ruthenium(II)-catalyzed synthesis of pyrrole- and indole-fused isocoumarins by C-H bond activation in DMF and water

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Sawant, S.G.; Dixneuf, P.H.

    stream_size 26907 stream_content_type text/plain stream_name ChemCatChem_8_1046a.pdf.txt stream_source_info ChemCatChem_8_1046a.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8 Author version...: ChemCatChem, vol.8(6); 2016; 1046-1050 Ruthenium(II) catalysed synthesis of pyrrole and indole fused isocoumarins via C-H bond activation in DMF and water† Keisham S. Singh*,a Sneha G. Sawanta, Pierre H. Dixneuf*,b Abstract: Pyrrole and indole...

  8. Synthesis of 2-[4-(10H-Substituted Phenothiazine-3-yl-6-Pyrimidin-2-Phenylthiol/ol/amine/thiol] Pyrroles

    Directory of Open Access Journals (Sweden)

    Meghasham Narule

    2007-01-01

    Full Text Available 2-[4-Hydroxy benz-1(propene-1-one]Pyrrole II on treatment with phenyl thiourea, guanidine carbonate, urea and thiourea in alcoholic KOH yielded compounds III, IV, V, VI which on treatment with different aryl anilines gave compounds VII, VIII, IX, X which under goes cyclisation with sulphur and iodine to give 2-[4-(10H-substituted phenothiazine-3-yl-6-pyrimidin-2-phenylthiol/-ol/-amine/-thiol] pyrrole XI(a-j, XII(a-j, XIII(a-j and XIV(a-j respectively. The structural products were characterized by elemental analysis and spectral data.

  9. meso-Octamethylcalix[4]pyrrole as an effective macrocyclic receptor for the univalent thallium cation in the gas phase: Experimental and theoretical study

    Science.gov (United States)

    Polášek, Miroslav; Makrlík, Emanuel; Kvíčala, Jaroslav; Křížová, Věra; Vaňura, Petr

    2018-02-01

    By using electrospray ionization mass spectrometry (ESI-MS), it was proven experimentally that the univalent thallium cation (Tl+) forms with meso-octamethylcalix[4]pyrrole (1) the cationic complex species 1 Tl+. When this kinetically stable cation-π complex 1 Tl+ is collisionally activated, it decomposes by elimination of the whole ligand 1 or small meso-octamethylcalix[4]pyrrole fragments. Further, applying quantum chemical DFT calculations, four different conformations of the resulting complex 1 Tl+ were derived. It means that under the present experimental conditions, this ligand 1 can be considered as a very effective macrocyclic receptor for the thallium cation.

  10. Teenage organophosphate insecticide poisoning: An ugly trend in ...

    African Journals Online (AJOL)

    UNIBEN

    is worsened by uncontrolled sale of organophosphorus insecticides on the streets and in open markets. We report ..... Nicotinic activity results in autonomic nervous system .... optimize outcome.23 Oximes are cholinesterase re-activators used ...

  11. Gas Chromaotography-Mass Spectrometry Analysis of Insecticidal ...

    African Journals Online (AJOL)

    Insecticidal Essential Oil Derived from Chinese Ainsliaea fragrans Champ ex Benth ... Methods: The essential oil of A. fragrans aerial parts was obtained by hydrodistillation and analyzed by ..... toxicity than the crude oil. Caryophyllene showed.

  12. Scepticism towards insecticide treated mosquito nets for malaria ...

    African Journals Online (AJOL)

    Scepticism towards insecticide treated mosquito nets for malaria control in rural ... especially among under-five year children and pregnant women in poor rural ... through social marketing strategy for malaria control prior to the introduction of ...

  13. Design, Synthesis and Insecticidal Activity of Novel Phenylurea Derivatives

    Directory of Open Access Journals (Sweden)

    Jialong Sun

    2015-03-01

    Full Text Available A series of novel phenylurea derivatives were designed and synthesized according to the method of active groups linkage and the principle of aromatic groups bioisosterism in this study. The structures of the novel phenylurea derivatives were confirmed based on ESI-MS, IR and 1H-NMR spectral data. All of the compounds were evaluated for the insecticidal activity against the third instars larvae of Spodoptera exigua Hiibner, Plutella xyllostella Linnaeus, Helicoverpa armigera Hubner and Pieris rapae Linne respectively, at the concentration of 10 mg/L. The results showed that all of the derivatives displayed strong insecticidal activity. Most of the compounds presented higher insecticidal activity against S. exigua than the reference compounds tebufenozide, chlorbenzuron and metaflumizone. Among the synthesized compounds, 3b, 3d, 3f, 4b and 4g displayed broad spectrum insecticidal activity.

  14. Neurotoxicological effects and the mode of action of pyrethroid insecticides

    NARCIS (Netherlands)

    Vijverberg, H.P.M.; Bercken, Joep van den

    1990-01-01

    Neuroexcitatory symptoms of acute poisoning of vertebrates by pyrethroids are related to the ability of these insecticides to modify electrical activity in various parts of the nervous system. Repetitive nerve activity, particularly in the sensory nervous system, membrane depolarization, and

  15. Effect of natural and chemical insecticides on Hyalopterus pruni and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-06-17

    Jun 17, 2008 ... Anthmis pseudocotula and their mixtures with chemical insecticide (Malathion) on growth of ... ed the use of natural extracts of Fagonia arabica, Salix ..... Studies on the efficacy of neem products against the aphid Aphis.

  16. Process optimization and insecticidal activity of alkaloids from the ...

    African Journals Online (AJOL)

    Process optimization and insecticidal activity of alkaloids from the root bark of Catalpa ovata G. Don by response surface methodology. ... Tropical Journal of Pharmaceutical Research. Journal Home · ABOUT THIS JOURNAL · Advanced ...

  17. Insect P450 inhibitors and insecticides: challenges and opportunities.

    Science.gov (United States)

    Feyereisen, René

    2015-06-01

    P450 enzymes are encoded by a large number of genes in insects, often over a hundred. They play important roles in insecticide metabolism and resistance, and growing numbers of P450 enzymes are now known to catalyse important physiological reactions, such as hormone metabolism or cuticular hydrocarbon synthesis. Ways to inhibit P450 enzymes specifically or less specifically are well understood, as P450 inhibitors are found as drugs, as fungicides, as plant growth regulators and as insecticide synergists. Yet there are no P450 inhibitors as insecticides on the market. As new modes of action are constantly needed to support insecticide resistance management, P450 inhibitors should be considered because of their high potential for insect selectivity, their well-known mechanisms of action and the increasing ease of rational design and testing. © 2014 Society of Chemical Industry.

  18. Gas Chromatography-Mass Spectrometric Analysis and Insecticidal ...

    African Journals Online (AJOL)

    HP

    Original Research Article. Gas Chromatography-Mass Spectrometric Analysis and ... into a natural fumigant/insecticide for the control of stored product insects. Keywords: Mallotus ..... stability as well as reduce cost. ACKNOWLEDGEMENT.

  19. Gas Chromatography-Mass Spectrometric Analysis and Insecticidal ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research ... apelta aerial parts was analyzed by gas chromatography/mass spectrometric (GC/MS) to determine its composition. ... into a natural fumigant/insecticide for the control of stored product insects.

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

    Data.gov (United States)

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

  1. PRN 73-4: Residual Insecticides in Food Handling Establishments

    Science.gov (United States)

    This notice provides a copy of a Federal Register notice published July 6, 1973, regarding certain insecticides used in food-handling establishments. It establishes certain definitions and requirements related to approval for crack and crevice treatment.

  2. Log bioassay of residual effectiveness of insecticides against bark beetles

    Science.gov (United States)

    Richard H. Smith

    1982-01-01

    Residual effectiveness of nine insecticides applied to bark was tested against western, mountain, and Jeffrey pine beetles. Ponderosa and Jeffrey pine trees were treated and logs cut from them 2 to 13 months later, and bioassayed with the three beetles. The insecticides were sprayed at the rate of 1 gal (3.8 l) per 40- or 80-ft² (3.6 or 7.2 m²) bark surface at varying...

  3. The use of insecticides to control insect pests

    OpenAIRE

    M Wojciechowska; P Stepnowski; M Gołębiowski

    2016-01-01

    Pesticides are used as plants protection products. Among those, insecticides serve as agents to control insects. When incorrectly applied, however these substances may negatively affect people's health and natural environment. Administration routes of insecticides depend on many factors and vary from spraying to fertilizers. These different methods influence how insects prey and how pests develop. Additionally, too frequent use of the same chemicals can lead to development of resi...

  4. Insecticidal activity of Trichilia claussenii (Meliaceae) fruits against Spodoptera frugiperda

    International Nuclear Information System (INIS)

    Nebo, Liliane; Matos, Andrea Pereira; Vieira, Paulo Cezar; Fernandes, Joao Batista; Silva, Maria Fatima das Gracas Fernandes da; Rodrigues, Ricardo Ribeiro

    2010-01-01

    An evaluation of the insecticidal activity of the fruits extracts of Trichilia claussenii was carried out and the methanol extract revealed to have strong insecticidal activity. The fractionation of methanol extract of T. claussenii seeds bioassay-guided against Spodoptera frugiperda has led to the identification of the ω-phenylalkyl and alkenyl fatty acids as active compounds in this extract. The structures of the compounds were proposed by spectroscopic analysis and comparison with literature data. (author)

  5. Organochlorine insecticide poisoning in Golden Langurs Trachypithecus geei

    Directory of Open Access Journals (Sweden)

    D.C. Pathak

    2011-07-01

    Full Text Available Organochlorine insecticide poisoning was recorded in three Golden Langurs (Trachypithecus geei in Chakrashila Wildlife Sanctuary (CWS in Kokrajhar district of Assam during the month of December, 2008. The poisoning was due to prolonged ingestion of rubber plant leaves sprayed with the insecticide in a rubber plantation adjacent to the sanctuary. Though no specific gross lesions were observed, histopathologically, centilobular hepatic necrosis, mild renal degeneration, necrotic enteritis, pulmonary congestion and neuronal degeneration were recorded in all three animals.

  6. Plant compounds insecticide activity against Coleoptera pests of stored products

    OpenAIRE

    MOREIRA, M.D.; PICANÇO, M.C.; BARBOSA, L.C. de A.; GUEDES, R.N.C.; CAMPOS, M.R. de; SILVA, G.A.; MARTINS, J.C.

    2008-01-01

    The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed...

  7. Pyrrole-phenylboronic acid: a novel monomer for dopamine recognition and detection based on imprinted electrochemical sensor.

    Science.gov (United States)

    Zhong, Min; Teng, Ying; Pang, Shufen; Yan, Liqin; Kan, Xianwen

    2015-02-15

    A molecular imprinting polymer (MIP) based electrochemical sensor was successfully prepared for dopamine (DA) recognition and detection using pyrrole-phenylboronic acid (py-PBA) as a novel electropolymerized monomer. py-PBA could form cyclic boronic ester bond with DA, thus endowing a double recognition capacity of the sensor to DA in the combination of the imprinted effect of MIP. Compared with the sensor prepared using pyrrole or phenylboronic acid as electropolymerized monomer, the present sensor exhibited a remarkable high imprinted factor to DA. The influence factors including pH value, the mole ratio between monomer and template molecule, electropolymerization scan rate, and scan cycles of electropolymerization process were investigated and optimized. Under the optimal conditions, the sensor could recognize DA from its analogs and monosaccharides. A linear ranging from 5.0 × 10(-8) to 1.0 × 10(-5) mol/L for the detection of DA was obtained with a detection limit of 3.3 × 10(-8) mol/L (S/N = 3). The sensor has been applied to analyze DA in injection samples with satisfactory results. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. A role of nanotube dangling pyrrole and oxygen functions in the electrochemical synthesis of polypyrrole/MWCNTs hybrid materials

    International Nuclear Information System (INIS)

    Krukiewicz, Katarzyna; Herman, Artur P.; Turczyn, Roman; Szymańska, Katarzyna; Koziol, Krzysztof K.K.; Boncel, Sławomir; Zak, Jerzy K.

    2014-01-01

    Highlights: • The effect of MWCNT functionalization on properties of PPy composites was explained. • The behavior of pristine, pyrrole-modified and oxidized MWCNT was explained. • Functionalization of MWCNT improved their dispersibility and processability. • Different mechanisms of (f-)MWCNT incorporation into PPy composites were explained. • Orientation of growing PPy chains was tailored through the addition of (f-)MWCNT. - Abstract: The effect of the functionalization of multi-walled carbon nanotubes (MWCNTs) on the process of electrochemical co-deposition of MWCNTs and polypyrrole (PPy), as well as the morphology of obtained composites have been demonstrated. As the nanotube components of the hybrids, three types of MWCNT were used, namely c-CVD derived (pristine) MWCNTs, their oxidized counterparts MWCNT-Ox and pyrrole-modified MWCNT-Py. The stability of pristine and functionalized MWCNTs (f-MWCNT) dispersions in tetrahydrofuran and water was studied together with the description of the process of formation PPy/(f-)MWCNT hybrid materials via electrochemical co-deposition. The structural and morphological properties of the hybrids were characterized by Raman spectroscopy, scanning electron microscopy and atomic force microscopy revealing substantial differences among hybrid materials in their surface morphology and the influence of MWCNT functionalization on the orientation of growing PPy chains

  9. A role of nanotube dangling pyrrole and oxygen functions in the electrochemical synthesis of polypyrrole/MWCNTs hybrid materials

    Energy Technology Data Exchange (ETDEWEB)

    Krukiewicz, Katarzyna, E-mail: katarzyna.krukiewicz@polsl.pl [Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, Strzody 9, 44-100 Gliwice (Poland); Herman, Artur P., E-mail: artur.herman@polsl.pl [Department of Organic Chemistry, Bioorganic Chemistry and Biotechnology, Silesian University of Technology, Krzywoustego 4, Gliwice 44-100 (Poland); Turczyn, Roman, E-mail: roman.turczyn@polsl.pl [Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, Strzody 9, 44-100 Gliwice (Poland); Szymańska, Katarzyna, E-mail: katarzyna.szymanska@polsl.pl [Department of Chemical and Process Engineering, Silesian University of Technology, Strzody 7, 44-100 Gliwice (Poland); Koziol, Krzysztof K.K., E-mail: kk292@cam.ac.uk [Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS (United Kingdom); Boncel, Sławomir, E-mail: slawomir.boncel@polsl.pl [Department of Organic Chemistry, Bioorganic Chemistry and Biotechnology, Silesian University of Technology, Krzywoustego 4, Gliwice 44-100 (Poland); Zak, Jerzy K., E-mail: jerzy.zak@polsl.pl [Department of Physical Chemistry and Technology of Polymers, Silesian University of Technology, Strzody 9, 44-100 Gliwice (Poland)

    2014-10-30

    Highlights: • The effect of MWCNT functionalization on properties of PPy composites was explained. • The behavior of pristine, pyrrole-modified and oxidized MWCNT was explained. • Functionalization of MWCNT improved their dispersibility and processability. • Different mechanisms of (f-)MWCNT incorporation into PPy composites were explained. • Orientation of growing PPy chains was tailored through the addition of (f-)MWCNT. - Abstract: The effect of the functionalization of multi-walled carbon nanotubes (MWCNTs) on the process of electrochemical co-deposition of MWCNTs and polypyrrole (PPy), as well as the morphology of obtained composites have been demonstrated. As the nanotube components of the hybrids, three types of MWCNT were used, namely c-CVD derived (pristine) MWCNTs, their oxidized counterparts MWCNT-Ox and pyrrole-modified MWCNT-Py. The stability of pristine and functionalized MWCNTs (f-MWCNT) dispersions in tetrahydrofuran and water was studied together with the description of the process of formation PPy/(f-)MWCNT hybrid materials via electrochemical co-deposition. The structural and morphological properties of the hybrids were characterized by Raman spectroscopy, scanning electron microscopy and atomic force microscopy revealing substantial differences among hybrid materials in their surface morphology and the influence of MWCNT functionalization on the orientation of growing PPy chains.

  10. Electrical and dielectric investigation of intercalated polypyrrole montmorillonite nanocomposite prepared by spontaneous polymerization of pyrrole into Fe(III)-montmorillonite

    Energy Technology Data Exchange (ETDEWEB)

    Zidi, Rabii, E-mail: rabiizidi@gmail.com [Physical Chemistry Laboratory for Mineral Materials and their Applications, National Center for Research in Materials Sciences (CNRSM), B.P.73, 8020 Soliman (Tunisia); Bekri-Abbes, Imene; Sdiri, Nasr [Physical Chemistry Laboratory for Mineral Materials and their Applications, National Center for Research in Materials Sciences (CNRSM), B.P.73, 8020 Soliman (Tunisia); Vimalanandan, Ashokanand; Rohwerder, Michael [Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf (Germany); Srasra, Ezzeddine [Physical Chemistry Laboratory for Mineral Materials and their Applications, National Center for Research in Materials Sciences (CNRSM), B.P.73, 8020 Soliman (Tunisia)

    2016-10-15

    Highlights: • We have prepared and characterized a Fe-MMT/PPy nanocomposites. • Investigate electrical conductivity and dielectric properties of the nanocomposite. • Investigate the temperature and frequency dependencies of alternating current conductivity of nanocomposites. - Abstract: Pyrrole was introduced into Fe(III)-exchanged montmorillonite to spontaneously polymerize within the interlayer resulting in the formation of intercalated polypyrrole-montmorillonite nanocomposite. The molar proportion of pyrrole to interlayer Fe{sup 3+} (R) has been varied from 0.5 to 5. The nanocomposite has been characterized by X-ray diffraction, Scanning Electronic Microscope, FTIR spectroscopy and impedance spectroscopy. It has been shown that intercalated polypyrrole montmorillonite nanocomposite was obtained. The results showed that the dc conductivity and dielectric properties of polypyrrole depend on R. The alternating current (ac) conductivity of the polymer obeys the power law, i.e., σ{sub ac}(ω) = Aω{sup s}. The alternating conductivity of nanocomposite was controlled by the correlated barrier hopping model. The activation energy for alternating current mechanism decreases with increasing frequency which confirms the hopping conduction to the dominant mechanism as compared with the dc activation energy. The dielectric relaxation mechanism was explained on the basis of complex dielectric modulus.

  11. (4-Nitrophenylmethyl 2,3-dihydro-1H-pyrrole-1-carboxylate: crystal structure and Hirshfeld analysis

    Directory of Open Access Journals (Sweden)

    Julio Zukerman-Schpector

    2018-03-01

    Full Text Available In the title compound, C12H12N2O4, the dihydropyrrole ring is almost planar (r.m.s. deviation = 0.0049 Å and is nearly coplanar with the adjacent C2O2 residue [dihedral angle = 4.56 (9°], which links to the 4-nitrobenzene substituent [dihedral angle = 4.58 (8°]. The molecule is concave, with the outer rings lying to the same side of the central C2O2 residue and being inclined to each other [dihedral angle = 8.30 (7°]. In the crystal, supramolecular layers parallel to (10-5 are sustained by nitrobenzene-C—H...O(carbonyl and pyrrole-C—H...O(nitro interactions. The layers are connected into a three-dimensional architecture by π(pyrrole–π(nitrobenzene stacking [inter-centroid separation = 3.7414 (10 Å] and nitro-O...π(pyrrole interactions.

  12. Impact of some selected insecticides application on soil microbial respiration.

    Science.gov (United States)

    Latif, M A; Razzaque, M A; Rahman, M M

    2008-08-15

    The aim of present study was to investigate the impact of selected insecticides used for controlling brinjal shoot and fruit borer on soil microorganisms and to find out the insecticides or nontoxic to soil microorganism the impact of nine selected insecticides on soil microbial respiration was studied in the laboratory. After injection of different insecticides solutions, the soil was incubated in the laboratory at room temperature for 32 days. The amount of CO2 evolved due to soil microbial respiration was determined at 2, 4, 8, 16, 24 and 32 days of incubation. Flubendiamide, nimbicidine, lambda-cyhalothrin, abamectin and thiodicarb had stimulatory effect on microbial respiration during the initial period of incubation. Chlorpyriphos, cartap and carbosulfan had inhibitory effect on microbial respiration and cypermethrin had no remarkable effect during the early stage of incubation. The negative effect of chlorpyriphos, cartap and carbosulfan was temporary, which was disappeared after 4 days of insecticides application. No effect of the selected insecticides on soil microorganisms was observed after 24 or 32 days of incubation.

  13. Thieno[3,4-c]Pyrrole-4,6-Dione-Based Polymer Acceptors for High Open-Circuit Voltage All-Polymer Solar Cells

    KAUST Repository

    Liu, Shengjian; Song, Xin; Thomas, Simil; Kan, Zhipeng; Cruciani, Federico; Laquai, Fré dé ric; Bredas, Jean-Luc; Beaujuge, Pierre

    2017-01-01

    limits the perspectives to meet the 10% efficiency threshold in all-polymer solar cells. This report examines two polymer acceptor analogs composed of thieno[3,4-c]pyrrole-4,6-dione (TPD) and 3,4-difluorothiophene ([2F]T) motifs, and their BHJ solar cell

  14. Thieno[3,4-c]pyrrole-4,6-dione-3,4-difluorothiophene Polymer Acceptors for Efficient All-Polymer Bulk Heterojunction Solar Cells

    KAUST Repository

    Liu, Shengjian

    2016-09-16

    Branched-alkyl-substituted poly(thieno[3,4-c]pyrrole-4,6-dione-alt-3,4-difluorothiophene) (PTPD[2F]T) can be used as a polymer acceptor in bulk heterojunction (BHJ) solar cells with a low-band-gap polymer donor (PCE10) commonly used with fullerenes. The

  15. In-situ optical spectroscopy and electronic properties of pyrrole sub-monolayers on Ga-rich GaAs(001)

    International Nuclear Information System (INIS)

    Bruhn, Thomas; Ewald, Marcel; Fimland, Bjørn-Ove; Kneissl, Michael; Esser, Norbert; Vogt, Patrick

    2011-01-01

    We report on the characterization of sub-monolayers of pyrrole adsorbed on Ga-rich GaAs(001) surfaces. The interfaces were characterized by scanning tunneling microscopy (STM), scanning tunneling spectroscopy (STS) and reflectance anisotropy spectroscopy (RAS) in a spectral range between 1.5 and 8 eV. The adsorption of pyrrole on Ga-rich GaAs(001) modifies the RAS spectrum of the clean GaAs surface significantly at the surface transitions at 2.2 and 3.5 eV indicating a chemisorption of the molecules. By the help of transients at these surface transitions during the adsorption process, we were able to prepare different molecular coverages from a sub-monolayer up to a complete molecular layer. The different coverages of pyrrole were imaged by STM and electronically characterized by STS. The measurements reveal that the adsorbed molecules electronically insulate the surface and indicate the formation of new interface states around −3.5 and +4.2 eV. The RAS measurements in the UV region show new anisotropies in the spectral range of the optical transitions of the adsorbed pyrrole molecules. Our measurements demonstrate the potential of optical and electronic spectroscopy methods for the characterization of atomically thin molecular layers on semiconductor surfaces allowing a direct access to the properties of single adsorbed molecules.

  16. Preparation of deuterated heterocyclic five-membered ring compounds (furan, thiophene, pyrrole, and derivatives) by base-catalyzed hydrogen isotope exchange with deuterium oxide

    International Nuclear Information System (INIS)

    Heinrich, K.H.; Herrmann, M.; Moebius, G.; Sprinz, H.

    1984-01-01

    Several deuterated heterocyclic compounds of the type of furan,thiophene and pyrrole were prepared by base-catalyzed proton exchange with deuterium oxide at temperatures above 423 K in a closed system. The determination of deuterium and its distribution within the molecules was carried out by mass spectrometry and 1 H nmr spectrometry. (author)

  17. Ion vs. ion pair receptor: NMR and DFT study of the interaction of Thallium and Cesium ions and ion pairs with meso-octamethylcalix[4]pyrrole

    Czech Academy of Sciences Publication Activity Database

    Kříž, Jaroslav; Dybal, Jiří; Makrlík, E.; Sedláková, Zdeňka

    2012-01-01

    Roč. 400, 25 May (2012), s. 19-28 ISSN 0301-0104 R&D Projects: GA ČR GA203/09/1478 Institutional research plan: CEZ:AV0Z40500505 Keywords : calix[4]pyrrole * cesium receptor * fluoride receptor Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.957, year: 2012

  18. The Synthesis of Novel 3-Substituted Poly(pyrroles) Bearing Crown-ether Moieties and a Study of their Electrochemical Properties

    DEFF Research Database (Denmark)

    Guernion, Nicolas J.L.; Blencowe, A.; Hayes, Wayne

    2006-01-01

    A series of fourteen novel pyrrole monomers substituted at the 3-position with aliphatic and aromatic crown-ether moieties have been synthesised in good yield and characterised extensively. Several of those compounds were electropolymerised successfully in acetonitrile, using both potentiostatic ...

  19. Insecticide mixtures could enhance the toxicity of insecticides in a resistant dairy population of Musca domestica L [corrected].

    Directory of Open Access Journals (Sweden)

    Hafiz Azhar Ali Khan

    Full Text Available House flies, Musca domestica L., are important pests of dairy operations worldwide, with the ability to adapt wide range of environmental conditions. There are a number of insecticides used for their management, but development of resistance is a serious problem. Insecticide mixtures could enhance the toxicity of insecticides in resistant insect pests, thus resulting as a potential resistance management tool. The toxicity of bifenthrin, cypermethrin, deltamethrin, chlorpyrifos, profenofos, emamectin benzoate and fipronil were assessed separately, and in mixtures against house flies. A field-collected population was significantly resistant to all the insecticides under investigation when compared with a laboratory susceptible strain. Most of the insecticide mixtures like one pyrethroid with other compounds evaluated under two conditions (1∶1-"A" and LC50: LC50-"B" significantly increased the toxicity of pyrethroids in the field population. Under both conditions, the combination indices of pyrethroids with other compounds, in most of the cases, were significantly below 1, suggesting synergism. The enzyme inhibitors, PBO and DEF, when used in combination with insecticides against the resistant population, toxicities of bifenthrin, cypermethrin, deltamethrin and emamectin were significantly increased, suggesting esterase and monooxygenase based resistance mechanism. The toxicities of bifenthrin, cypermethrin and deltamethrin in the resistant population of house flies could be enhanced by the combination with chlorpyrifos, profenofos, emamectin and fipronil. The findings of the present study might have practical significance for resistance management in house flies.

  20. Insecticide Mixtures Could Enhance the Toxicity of Insecticides in a Resistant Dairy Population of Musca domestica L

    Science.gov (United States)

    Khan, Hafiz Azhar Ali; Akram, Waseem; Shad, Sarfraz Ali; Lee, Jong-Jin

    2013-01-01

    House flies, Musca domestica L., are important pests of dairy operations worldwide, with the ability to adapt wide range of environmental conditions. There are a number of insecticides used for their management, but development of resistance is a serious problem. Insecticide mixtures could enhance the toxicity of insecticides in resistant insect pests, thus resulting as a potential resistance management tool. The toxicity of bifenthrin, cypermethrin, deltamethrin, chlorpyrifos, profenofos, emamectin benzoate and fipronil were assessed separately, and in mixtures against house flies. A field-collected population was significantly resistant to all the insecticides under investigation when compared with a laboratory susceptible strain. Most of the insecticide mixtures like one pyrethroid with other compounds evaluated under two conditions (1∶1-“A” and LC50: LC50-“B”) significantly increased the toxicity of pyrethroids in the field population. Under both conditions, the combination indices of pyrethroids with other compounds, in most of the cases, were significantly below 1, suggesting synergism. The enzyme inhibitors, PBO and DEF, when used in combination with insecticides against the resistant population, toxicities of bifenthrin, cypermethrin, deltamethrin and emamectin were significantly increased, suggesting esterase and monooxygenase based resistance mechanism. The toxicities of bifenthrin, cypermethrin and deltamethrin in the resistant population of house flies could be enhanced by the combination with chlorpyrifos, profenofos, emamectin and fipronil. The findings of the present study might have practical significance for resistance management in house flies. PMID:23613758

  1. The gut microbiota of insecticide-resistant insects houses insecticide-degrading bacteria: A potential source for biotechnological exploitation

    Science.gov (United States)

    de Almeida, Luis Gustavo; de Moraes, Luiz Alberto Beraldo; Trigo, José Roberto; Omoto, Celso

    2017-01-01

    The exploration of new niches for microorganisms capable of degrading recalcitrant molecules is still required. We hypothesized the gut microbiota associated with insect-resistant lines carry pesticide degrading bacteria, and predicted they carry bacteria selected to degrade pesticides they were resistant to. We isolated and accessed the pesticide-degrading capacity of gut bacteria from the gut of fifth instars of Spodoptera frugiperda strains resistant to lambda-cyhalothrin, deltamethrin, chlorpyrifos ethyl, spinosad and lufenuron, using insecticide-selective media. Sixteen isolates belonging to 10 phylotypes were obtained, from which four were also associated with the susceptible strain. However, growth of gut bacteria associated with larvae from the susceptible strain was not obtained in any of the insecticide-based selective media tested. Growth of isolates was affected by the concentration of insecticides in the media, and all grew well up to 40 μg/ml. The insecticide-degrading capacity of selected isolates was assessed by GC or LC-MS/MS analyses. In conclusion, resistant strains of S. frugiperda are an excellent reservoir of insecticide-degrading bacteria with bioremediation potential. Moreover, gut-associated bacteria are subjected to the selection pressure imposed by insecticides on their hosts and may influence the metabolization of pesticides in insects. PMID:28358907

  2. The gut microbiota of insecticide-resistant insects houses insecticide-degrading bacteria: A potential source for biotechnological exploitation.

    Directory of Open Access Journals (Sweden)

    Luis Gustavo de Almeida

    Full Text Available The exploration of new niches for microorganisms capable of degrading recalcitrant molecules is still required. We hypothesized the gut microbiota associated with insect-resistant lines carry pesticide degrading bacteria, and predicted they carry bacteria selected to degrade pesticides they were resistant to. We isolated and accessed the pesticide-degrading capacity of gut bacteria from the gut of fifth instars of Spodoptera frugiperda strains resistant to lambda-cyhalothrin, deltamethrin, chlorpyrifos ethyl, spinosad and lufenuron, using insecticide-selective media. Sixteen isolates belonging to 10 phylotypes were obtained, from which four were also associated with the susceptible strain. However, growth of gut bacteria associated with larvae from the susceptible strain was not obtained in any of the insecticide-based selective media tested. Growth of isolates was affected by the concentration of insecticides in the media, and all grew well up to 40 μg/ml. The insecticide-degrading capacity of selected isolates was assessed by GC or LC-MS/MS analyses. In conclusion, resistant strains of S. frugiperda are an excellent reservoir of insecticide-degrading bacteria with bioremediation potential. Moreover, gut-associated bacteria are subjected to the selection pressure imposed by insecticides on their hosts and may influence the metabolization of pesticides in insects.

  3. Enzymes and Inhibitors in Neonicotinoid Insecticide Metabolism

    Science.gov (United States)

    Shi, Xueyan; Dick, Ryan A.; Ford, Kevin A.; Casida, John E.

    2009-01-01

    Neonicotinoid insecticide metabolism involves considerable substrate specificity and regioselectivity of the relevant CYP450, aldehyde oxidase, and phase II enzymes. Human CYP450 recombinant enzymes carry out the following conversions: CYP3A4, 2C19 and 2B6 for thiamethoxam (TMX) to clothianidin (CLO); 3A4, 2C19 and 2A6 for CLO to desmethyl-CLO; 2C19 for TMX to desmethyl-TMX. Human liver aldehyde oxidase reduces the nitro substituent of CLO to nitroso much more rapidly than that of TMX. Imidacloprid (IMI), CLO and several of their metabolites do not give detectable N-glucuronides but 5-hydroxy-IMI, 4,5-diol-IMI and 4-hydroxy-thiacloprid are converted to O-glucuronides in vitro with mouse liver microsomes and UDP-glucuronic acid or in vivo in mice. Mouse liver cytosol with S-adenosylmethionine converts desmethyl-CLO to CLO but not desmethyl-TMX to TMX. Two organophosphorus CYP450 inhibitors partially block IMI, thiacloprid and CLO metabolism in vivo in mice, elevating the brain and liver levels of the parent compounds while reducing amounts of the hydroxylated metabolites. PMID:19391582

  4. Azobenzene Modified Imidacloprid Derivatives as Photoswitchable Insecticides: Steering Molecular Activity in a Controllable Manner

    Science.gov (United States)

    Xu, Zhiping; Shi, Lina; Jiang, Danping; Cheng, Jiagao; Shao, Xusheng; Li, Zhong

    2015-10-01

    Incorporating the photoisomerizable azobenzene into imidacloprid produced a photoswitchable insecticidal molecule as the first neonicotinoid example of remote control insecticide performance with spatiotemporal resolution. The designed photoswitchable insecticides showed distinguishable activity against Musca both in vivo and in vitro upon irradiation. Molecular docking study further suggested the binding difference of the two photoisomers. The generation of these photomediated insecticides provides novel insight into the insecticidal activity facilitating further investigation on the functions of insect nicotinic acetylcholine receptors and opens a novel way to control and study insect behavior on insecticide poisoning using light.

  5. Zinc hexacyanoferrate film as an effective protecting layer in two-step and one-step electropolymerization of pyrrole on zinc substrate

    Energy Technology Data Exchange (ETDEWEB)

    Pournaghi-Azar, M.H. [Electroanalytical Chemistry Laboratory, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)]. E-mail: pournaghiazar@tabrizu.ac.ir; Nahalparvari, H. [Electroanalytical Chemistry Laboratory, Faculty of Chemistry, University of Tabriz, Tabriz (Iran, Islamic Republic of)

    2005-03-15

    The two-step and one-step electrosynthesis processes of polypyrrole (PPy) films on the zinc substrate are described. The two-step process includes (i) the zinc surface pretreatment with hexacyanoferrate ion in the aqueous medium in order to form a zinc hexacyanoferrate (ZnHCF) film non-blocking passive layer on the surface and with the view to prevent its reactivity and (ii) electropolymerization of pyrrole on the ZnHCF vertical bar Zn-modified electrode in aqueous pyrrole solution. In this context, both the non-electrolytic and electrolytic procedures were adapted, and the effect of some experimental conditions such as supporting electrolyte, pH and temperature of the solution at the zinc surface pretreatment step as well as pyrrole concentration and electrochemical techniques at the polymerization step was investigated. By optimizing the experimental conditions in both steps, we have obtained a homogeneous and strongly adherent PPy films on the zinc substrate. The one-step process is based on the use of an aqueous medium containing Fe(CN){sub 6}{sup 4-} and pyrrole. The ferrocyanide ion passivates the substrate by formation of ZnHCF film during the electropolymerization process of pyrrole and therefore makes it possible to obtain strongly adherent PPy films, with controlled thickness, either by cyclic voltammetry or by electrolysis at constant current or constant potential without any previously treatment of the zinc electrode surface. The polypyrrole films deposited on the zinc electrode were characterized by cyclic voltammetry and scanning electron microscopic (SEM) measurement.

  6. Climate change, agricultural insecticide exposure, and risk for freshwater communities.

    Science.gov (United States)

    Kattwinkel, Mira; Kühne, Jan-Valentin; Foit, Kaarina; Liess, Matthias

    2011-09-01

    Climate change exerts direct effects on ecosystems but has additional indirect effects due to changes in agricultural practice. These include the increased use of pesticides, changes in the areas that are cultivated, and changes in the crops cultivated. It is well known that pesticides, and in particular insecticides, affect aquatic ecosystems adversely. To implement effective mitigation measures it is necessary to identify areas that are affected currently and those that will be affected in the future. As a consequence, we predicted potential exposure to insecticide (insecticide runoff potential, RP) under current conditions (1990) and under a model scenario of future climate and land use (2090) using a spatially explicit model on a continental scale, with a focus on Europe. Space-for-time substitution was used to predict future levels of insecticide application, intensity of agricultural land use, and cultivated crops. To assess the indirect effects of climate change, evaluation of the risk of insecticide exposure was based on a trait-based, climate-insensitive indicator system (SPEAR, SPEcies At Risk). To this end, RP and landscape characteristics that are relevant for the recovery of affected populations were combined to estimate the ecological risk (ER) of insecticides for freshwater communities. We predicted a strong increase in the application of, and aquatic exposure to, insecticides under the future scenario, especially in central and northern Europe. This, in turn, will result in a severe increase in ER in these regions. Hence, the proportion of stream sites adjacent to arable land that do not meet the requirements for good ecological status as defined by the EU Water Framework Directive will increase (from 33% to 39% for the EU-25 countries), in particular in the Scandinavian and Baltic countries (from 6% to 19%). Such spatially explicit mapping of risk enables the planning of adaptation and mitigation strategies including vegetated buffer strips and

  7. [18F]fluoromethylated phenyl-pyrroles and 7-azaindole analog as potential dopamine D4 receptor imaging agents

    International Nuclear Information System (INIS)

    Ji, D. Y.; Oh, S. Z.; Choi, Y. S.; Lee, K. C.; Kim, S. E.; Choi, Y.; Lee, K. H.; Kim, B. T.

    1997-01-01

    An association between the dopamine D 4 receptor and schizophrenia was recently suggested and the D 4 receptor antagonists may thus have potential in elucidating the role of the receptor in schizophrenic patients. The purpose of this study was to develop some of these antagonists as potential dopamine D 4 receptor imaging agents for PET. We have prepared 1-(3-[ 18 F]fluoromethylphenyl)-3-([4-(pyridin-2-yl)piperazin-1-yl)methyl) pyrrole (1), 1-(3-[ 18 F]fluoromethylphenyl)-3-([4-(pyridin-2-yl)piperazin-1-yl)methyl) pyrrole (2), and 3-([4-(4-[ 18 F]fluoro methylbenzyl)piperazin-1-yl)methyl)-1H-pyrrolo(2,3,-b)pyridine (3) as potential imaging agents for the dopamine D 4 receptor for PET. The compounds [ 18 F]1 and [ 18 F]2 were prepared by coupling of (3-[ 18 F]fluoromethylphenyl)-pyrrol-1- yl-3-aldehyde and the piperazine moiety in the presence of NaBH 3 CN. The [ 18 F]fluorinated aldehyde was obtained in 60-85% yield by the displacement of the corresponding mesylate with F-18-(THF, 90 .deg. C, 5 min). HPLC purification (Alltech Econosil C-18 columm, 250 x 10 mm, 35: 65 = 0.1M NH 4 CI 2 H : CH 3 OH, 4 ml/min, t R =26.6 min) gave the [ 18 F]1 and [ 18 F]2 in 7-12% yield. In the case of azaindole 3, a methlene link was inserted between the piperazinyl and a fluoromethyl phenyl group. Radiochemical synthesis of the [ 18 F]3 was carried out by coupling of the piperazne moiety and [ 18 F]fluoromethylbenzyl mesylate in the presence of NEt 3 (3:1-CH 3 CN: DMF, 120 .deg. C, 30 min). Purification was carried out by HPLC using a C-18 column (Alltech Econosil, 50 x 10 mm, 100% 0.1M NH 4 CO 2 H for 5 min followed by 40:60=0.1 M NH 4 CO 2 H : MeOH, 4 ml/min t R =28.7 min). The time of synthesis including HPLC purification was 100 min. The overall yield of [ 18 F]3 was 10-15% with a radiochemical purity better than 97% and a specific activity greater than 1000 ci/mmol

  8. Plant compounds insecticide activity against Coleoptera pests of stored products

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Marcio Dionizio; Picanco, Marcelo Coutinho; Guedes, Raul Narciso Carvalho; Campos, Mateus Ribeiro de; Silva, Gerson Adriano; Martins, Julio Claudio [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Biologia Animal]. E-mail: marcio.dionizio@gmail.com; picanco@ufv.br; guedes@ufv.br; mateusc3@yahoo.com.br; agronomiasilva@yahoo.com.br

    2007-07-15

    The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed (Datura stramonium L.), baleeira herb (Cordia verbenacea L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.), and billy goat weed or mentrasto (Ageratum conyzoides L.). The insecticide activity of hexane and ethanol extracts from those plants on R. dominica was evaluated. Among them, only hexane extract of A. conyzoides showed insecticide activity; the hexane extract of this species was successively fractionated by silica gel column chromatography, for isolation and purification of the active compounds. Compounds 5,6,7,8,3',4',5'-heptamethoxyflavone; 5,6,7,8,3'-pentamethoxy-4',5'-methilenedioxyflavone and coumarin were identified. However, only coumarin showed insecticide activity against three insect pests (LD{sub 50} from 2.72 to 39.71 mg g{sup -1} a.i.). The increasing order of insects susceptibility to coumarin was R. dominica, S. zeamais and O. surinamensis. (author)

  9. Insecticide mixtures for mosquito net impregnation against malaria vectors

    Directory of Open Access Journals (Sweden)

    Corbel V.

    2002-09-01

    Full Text Available Insecticides belonging to the pyrethroid family are the only compounds currently available for the treatment of mosquito nets. Unfortunately, some malaria vector species have developed resistance to pyrethroids and the lack of alternative chemical categories is a great concern. One strategy for resistance management would be to treat mosquito nets with a mixture associating two insecticides having different modes of action. This study presents the results obtained with insecticide mixtures containing several proportions of bifenthrin (a pyrethroid insecticide and carbosulfan (a carbamate insecticide. The mixtures were sprayed on mosquito net samples and their efficacy were tested against a susceptible strain of Anopheles gambiae, the major malaria vector in Africa. A significant synergism was observed with a mixture containing 25 mg/m2 of bifenthrin (half the recommended dosage for treated nets and 6.25 mg/m2 of carbosulfan (about 2 % of the recommended dosage. The observed mortality was significantly more than expected in the absence of any interaction (80 % vs 41 % and the knock-down effect was maintained, providing an effective barrier against susceptible mosquitoes.

  10. Mass spectrometric analyses of organophosphate insecticide oxon protein adducts.

    Science.gov (United States)

    Thompson, Charles M; Prins, John M; George, Kathleen M

    2010-01-01

    Organophosphate (OP) insecticides continue to be used to control insect pests. Acute and chronic exposures to OP insecticides have been documented to cause adverse health effects, but few OP-adducted proteins have been correlated with these illnesses at the molecular level. Our aim was to review the literature covering the current state of the art in mass spectrometry (MS) used to identify OP protein biomarkers. We identified general and specific research reports related to OP insecticides, OP toxicity, OP structure, and protein MS by searching PubMed and Chemical Abstracts for articles published before December 2008. A number of OP-based insecticides share common structural elements that result in predictable OP-protein adducts. The resultant OP-protein adducts show an increase in molecular mass that can be identified by MS and correlated with the OP agent. Customized OP-containing probes have also been used to tag and identify protein targets that can be identified by MS. MS is a useful and emerging tool for the identification of proteins that are modified by activated organophosphate insecticides. MS can characterize the structure of the OP adduct and also the specific amino acid residue that forms the key bond with the OP. Each protein that is modified in a unique way by an OP represents a unique molecular biomarker that with further research can lead to new correlations with exposure.

  11. Insecticides promote viral outbreaks by altering herbivore competition.

    Science.gov (United States)

    Pan, Huipeng; Preisser, Evan L; Chu, Dong; Wang, Shaoli; Wu, Qingjun; Carriére, Yves; Zhou, Xuguo; Zhang, Youjun

    2015-09-01

    While the management of biological invasions is often characterized by a series of single-specieg decisions, invasive species exist within larger food webs. These biotic interactions can alter the impact of control/eradication programs and may cause suppression efforts to inadvertently facilitate invasion spread and impact. We document the rapid replacement of the invasive Bemisia Middle East-Asia Minor I (MEAM1) cryptic biotype by the cryptic Mediterranean (MED) biotype throughout China and demonstrate that MED is more tolerant of insecticides and a better vector of tomato yellow leaf curl virus (TYLCV) than MEAMJ. While MEAM1 usually excludes MED under natural conditions, insecticide application reverses the MEAM1-MED competitive hierarchy and allows MED to exclude MEAMI. The insecticide-mediated success of MED has led to TYLCV outbreaks throughout China. Our work strongly supports the hypothesis that insecticide use in China reverses the MEAMl-MED competitive hierarchy and allows MED to displace MEAM1 in managed landscapes. By promoting the dominance of a Bemisia species that is a competent viral vector, insecticides thus increase the spread and impact of TYLCV in heterogeneous agroecosystems.

  12. The global status of insect resistance to neonicotinoid insecticides.

    Science.gov (United States)

    Bass, Chris; Denholm, Ian; Williamson, Martin S; Nauen, Ralf

    2015-06-01

    The first neonicotinoid insecticide, imidacloprid, was launched in 1991. Today this class of insecticides comprises at least seven major compounds with a market share of more than 25% of total global insecticide sales. Neonicotinoid insecticides are highly selective agonists of insect nicotinic acetylcholine receptors and provide farmers with invaluable, highly effective tools against some of the world's most destructive crop pests. These include sucking pests such as aphids, whiteflies, and planthoppers, and also some coleopteran, dipteran and lepidopteran species. Although many insect species are still successfully controlled by neonicotinoids, their popularity has imposed a mounting selection pressure for resistance, and in several species resistance has now reached levels that compromise the efficacy of these insecticides. Research to understand the molecular basis of neonicotinoid resistance has revealed both target-site and metabolic mechanisms conferring resistance. For target-site resistance, field-evolved mutations have only been characterized in two aphid species. Metabolic resistance appears much more common, with the enhanced expression of one or more cytochrome P450s frequently reported in resistant strains. Despite the current scale of resistance, neonicotinoids remain a major component of many pest control programmes, and resistance management strategies, based on mode of action rotation, are of crucial importance in preventing resistance becoming more widespread. In this review we summarize the current status of neonicotinoid resistance, the biochemical and molecular mechanisms involved, and the implications for resistance management. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Insecticidal and Nematicidal Activities of Novel Mimosine Derivatives

    Directory of Open Access Journals (Sweden)

    Binh Cao Quan Nguyen

    2015-09-01

    Full Text Available Mimosine, a non-protein amino acid, is found in several tropical and subtropical plants, which has high value for medicine and agricultural chemicals. Here, in continuation of works aimed to development of natural product-based pesticidal agents, we present the first significant findings for insecticidal and nematicidal activities of novel mimosine derivatives. Interestingly, mimosinol and deuterated mimosinol (D-mimosinol from mimosine had strong insecticidal activity which could be a result of tyrosinase inhibition (IC50 = 31.4 and 46.1 μM, respectively. Of synthesized phosphoramidothionate derivatives from two these amino alcohols, two compounds (1a and 1b showed high insecticidal activity (LD50 = 0.5 and 0.7 μg/insect, respectively with 50%–60% mortality at 50 μg/mL which may be attributed to acetylcholinesterase inhibition. Compounds 1a and 1b also had strong nematicidal activity with IC50 = 31.8 and 50.2 μM, respectively. Our results suggest that the length of the alkyl chain and the functional group at the C5-position of phosphoramidothionates derived from mimosinol and d-mimosinol are essential for the insecticidal and nematicidal activities. These results reveal an unexplored scaffold as new insecticide and nematicide.

  14. Plant compounds insecticide activity against Coleoptera pests of stored products

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Marcio Dionizio; Picanco, Marcelo Coutinho; Guedes, Raul Narciso Carvalho; Campos, Mateus Ribeiro de; Silva, Gerson Adriano; Martins, Julio Claudio [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Biologia Animal; br, picanco@ufv; br, guedes@ufv; br, mateusc3@yahoo com; br, agronomiasilva@yahoo com

    2007-07-15

    The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed (Datura stramonium L.), baleeira herb (Cordia verbenacea L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.), and billy goat weed or mentrasto (Ageratum conyzoides L.). The insecticide activity of hexane and ethanol extracts from those plants on R. dominica was evaluated. Among them, only hexane extract of A. conyzoides showed insecticide activity; the hexane extract of this species was successively fractionated by silica gel column chromatography, for isolation and purification of the active compounds. Compounds 5,6,7,8,3',4',5'-heptamethoxyflavone; 5,6,7,8,3'-pentamethoxy-4',5'-methilenedioxyflavone and coumarin were identified. However, only coumarin showed insecticide activity against three insect pests (LD{sub 50} from 2.72 to 39.71 mg g{sup -1} a.i.). The increasing order of insects susceptibility to coumarin was R. dominica, S. zeamais and O. surinamensis. (author)

  15. Plant compounds insecticide activity against Coleoptera pests of stored products

    International Nuclear Information System (INIS)

    Moreira, Marcio Dionizio; Picanco, Marcelo Coutinho; Guedes, Raul Narciso Carvalho; Campos, Mateus Ribeiro de; Silva, Gerson Adriano; Martins, Julio Claudio; julioufv@yahoo.com.br

    2007-01-01

    The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed (Datura stramonium L.), baleeira herb (Cordia verbenacea L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.), and billy goat weed or mentrasto (Ageratum conyzoides L.). The insecticide activity of hexane and ethanol extracts from those plants on R. dominica was evaluated. Among them, only hexane extract of A. conyzoides showed insecticide activity; the hexane extract of this species was successively fractionated by silica gel column chromatography, for isolation and purification of the active compounds. Compounds 5,6,7,8,3',4',5'-heptamethoxyflavone; 5,6,7,8,3'-pentamethoxy-4',5'-methilenedioxyflavone and coumarin were identified. However, only coumarin showed insecticide activity against three insect pests (LD 50 from 2.72 to 39.71 mg g -1 a.i.). The increasing order of insects susceptibility to coumarin was R. dominica, S. zeamais and O. surinamensis. (author)

  16. An insecticidal toxin from Nephila clavata spider venom.

    Science.gov (United States)

    Jin, Lin; Fang, Mingqian; Chen, Mengrou; Zhou, Chunling; Ombati, Rose; Hakim, Md Abdul; Mo, Guoxiang; Lai, Ren; Yan, Xiuwen; Wang, Yumin; Yang, Shilong

    2017-07-01

    Spiders are the most successful insect predators given that they use their venom containing insecticidal peptides as biochemical weapons for preying. Due to the high specificity and potency of peptidic toxins, discoveries of insecticidal toxins from spider venom have provided an opportunity to obtain natural compounds for agricultural applications without affecting human health. In this study, a novel insecticidal toxin (μ-NPTX-Nc1a) was identified and characterized from the venom of Nephila clavata. Its primary sequence is GCNPDCTGIQCGWPRCPGGQNPVMDKCVSCCPFCPPKSAQG which was determined by automated Edman degradation, cDNA cloning, and MS/MS analysis. BLAST search indicated that Nc1a shows no similarity with known peptides or proteins, indicating that Nc1a belongs to a novel family of insecticidal peptide. Nc1a displayed inhibitory effects on Na V and K V channels in cockroach dorsal unpaired median neurons. The median lethal dose (LD50) of Nc1a on cockroach was 573 ng/g. Herein, a study that identifies a novel insecticidal toxin, which can be a potential candidate and/or template for the development of bioinsecticides, is presented.

  17. Evaluación de algunos insecticidas para el control de la «polilla del tomate», Tuta absoluta (Lepidoptera: Gelechiidae y su efecto residual sobre el parasitoide Trichogrammatoidea bactrae (Hymenoptera: Trichogrammatidae Efficacy of insecticides against the «tomato moth», Tuta absoluta (Lepidoptera: Gelechiidae and their residual effects on the parasitoid Trichogrammatoidea bactrae (Hymenoptera: Trichogrammatidae

    Directory of Open Access Journals (Sweden)

    María B. Riquelme Virgala

    2006-12-01

    Full Text Available La «polilla del tomate», Tuta absoluta (Meyrick, es una plaga clave de este cultivo en Argentina. Su manejo integrado debería incluir una selección de productos fitosanitarios que sean eficaces para su control y, al mismo tiempo, selectivos respecto de sus enemigos naturales. El objetivo de este trabajo fue evaluar la capacidad de control de los insecticidas triflumurón, clorfenapir, abamectin y una cepa experimental de Bacillus thuringiensis (Bt sobre la plaga, y el poder residual de los mismos sobre Trichogrammatoidea bactrae Nagaraja. Se registró la mortalidad de la polilla cada cuatro días, desde la aplicación hasta la emergencia de los adultos. El efecto sobre el parasitoide, se evaluó a través del número de huevos parasitados por hembra expuesta durante 48 horas a folíolos tratados, y su mortalidad luego de 1, 3, 7, 14 y 30 días de la pulverización. Todos los productos ocasionaron una mortalidad de T. absoluta mayor al 65% después de 12 días de aplicados. El Bt fue el único insecticida que no afectó la supervivencia y el parasitismo de T. bactrae . Estos resultados aportan información de interés para la selección de plaguicidas, a emplearse en programas de manejo integrado.The «tomato moth», Tuta absoluta (Meyrick is one of the key pests of tomato crops in Argentina. The compatible use of chemical and biological control is the main purpose of integrated pest management. Selective pesticides that can be successfully used to control pest without adverse side effects on natural enemies are highly required. The aim of this work was to evaluate the efficacy of control of T. absoluta and the residual effect on the oophagous parasitoid, Trichogrammatoidea bactrae Nagaraja of the following insecticides: triflumuron, abamectin, chlorfenapyr, and an experimental strain of Bacillus thuringiensis (Bt. Mortality of T. absoluta was evaluated every 4 days from pesticide spraying until adult emergency. The effect of pesticides on

  18. Nano-silver mediated polymerization of pyrrole: synthesis and gas sensing properties of polypyrrole (PPy)/Ag nano-composite.

    Science.gov (United States)

    Kate, Kunal H; Damkale, Shubhangi R; Khanna, P K; Jain, G H

    2011-09-01

    Thermal polymerization of pyrrole was performed using silver nitrate as source of silver ions followed by its conversion to Polypyrrole (PPy)/Ag nano-comoposites without using any external oxidizing agent or solvent. The formation of PPy was monitored by UV-Visible absorption spectroscopy showing a band at approximately 464 nm. XRD measurement confirmed characteristic peaks for face centered cubic (fcc) silver and presence of PPy at 2 theta of approximately 23 degrees suggesting the formation of PPy/Ag nanocomposite. Transmission electron microscopy (TEM) images showed non-aggregated spherical Ag nano-particles of about 5-10 nm. PPy/Ag thick film acts as a NH3 sensor at 100 degrees C, a H2S sensor at 250 degrees C and CO2 sensor at 350 degrees C. The thick films showed capability to recognize various gases at different operating temperature.

  19. Design and modelling of enzyme/poly-pyrrole modified electrodes for bio-catalyzed electro-synthesis processes

    International Nuclear Information System (INIS)

    Gros, Pierre

    1996-01-01

    This research thesis reports a study which aims at developing, analyzing and integrating an electrode-enzyme interface within an electro-enzymatic reactor to develop electrochemical biosensors. The adopted method comprises a confinement of the enzyme at the electrode surface by means of an electro-formed poly-pyrrole film. The author reports an experimental and theoretical study of the coupling between electrochemical reaction, enzymatic reaction and matter transfer in the polymer in order to better understand the operation of so-modified electrodes. Different parameters have an influence on the reaction rate. A numerical model (validated by experiments) allows the identification of the reaction limiting stages. A new elaboration protocol allows the polymer permeability to be increased. The interface is first applied to the reduction of the NAD coenzyme, and the process is also applied to the production of gluconic acid [fr

  20. Hemispherand-Strapped Calix[4]pyrrole: An Ion-pair Receptor for the Recognition and Extraction of Lithium Nitrite.

    Science.gov (United States)

    He, Qing; Zhang, Zhan; Brewster, James T; Lynch, Vincent M; Kim, Sung Kuk; Sessler, Jonathan L

    2016-08-10

    The hemispherand-strapped calix[4]pyrrole (1) acts as an ion pair receptor that exhibits selectivity for lithium salts. In organic media (CD2Cl2 and CD3OD, v/v, 9:1), receptor 1 binds LiCl with high preference relative to NaCl, KCl, and RbCl. DFT calculations provided support for the observed selectivity. Single crystal structures of five different lithium ion-pair complexes of 1 were obtained. In the case of LiCl, a single bridging water molecule between the lithium cation and chloride anion was observed, while tight contact ion pairs were observed in the case of the LiBr, LiI, LiNO3, and LiNO2 salts. Receptor 1 proved effective as an extractant for LiNO2 under both model solid-liquid and liquid-liquid extraction conditions.

  1. Modular synthesis and in vitro and in vivo antimalarial assessment of C-10 pyrrole mannich base derivatives of artemisinin.

    Science.gov (United States)

    Pacorel, Bénédicte; Leung, Suet C; Stachulski, Andrew V; Davies, Jill; Vivas, Livia; Lander, Hollie; Ward, Stephen A; Kaiser, Marcel; Brun, Reto; O'Neill, Paul M

    2010-01-28

    In two steps from dihydroartemisinin, a small array of 16 semisynthetic C-10 pyrrole Mannich artemisinin derivatives (7a-p) have been prepared in moderate to excellent yield. In vitro analysis against both chloroquine sensitive and resistant strains has demonstrated that these analogues have nanomolar antimalarial activity, with several compounds being more than 3 times more potent than the natural product artemisinin. In addition to a potent antimalarial profile, these molecules also have very high in vitro therapeutic indices. Analysis of the optimal Mannich side chain substitution for in vitro and in vivo activity reveals that the morpholine and N-methylpiperazine Mannich side chains provide analogues with the best activity profiles, both in vitro and in vivo in the Peter's 4 day test.

  2. Intermediate Syndrome Following Organophosphate Insecticide Poisoning

    Directory of Open Access Journals (Sweden)

    Chen-Chang Yang

    2007-11-01

    Full Text Available Acute organophosphate insecticide poisoning can manifest 3 different phases of toxic effects, namely, acute cholinergic crisis, intermediate syndrome (IMS, and delayed neuropathy. Among them, IMS has been considered as a major contributing factor of organophosphate-related morbidity and mortality because of its frequent occurrence and probable consequence of respiratory failure. Despite a high incidence, the pathophysiology that underlies IMS remains unclear. Previously proposed mechanisms of IMS include different susceptibility of various cholinergic receptors, muscle necrosis, prolonged acetylcholinesterase inhibition, inadequate oxime therapy, downregulation or desensitization of postsynaptic acetylcholine receptors, failure of postsynaptic acetylcholine release, and oxidative stress-related myopathy. The clinical manifestations of IMS typically occur within 24 to 96 hours, affecting conscious patients without cholinergic signs, and involve the muscles of respiration, proximal limb muscles, neck flexors, and muscles innervated by motor cranial nerves. With appropriate therapy that commonly includes artificial respiration, complete recovery develops 5–18 days later. Patients with atypical manifestations of IMS, especially a relapse or a continuum of acute cholinergic crisis, however, were frequently reported in clinical studies of IMS. The treatment of IMS is mainly supportive. Nevertheless, because IMS generally concurs with severe organophosphate toxicity and persistent inhibition of acetylcholinesterase, early aggressive decontamination, appropriate antidotal therapy, and prompt institution of ventilatory support should be helpful in ameliorating the magnitude and/or the incidence of IMS. Although IMS is well recognized as a disorder of neuromuscular junctions, its exact etiology, incidence, and risk factors are not clearly defined because existing studies are largely small-scale case series and do not employ a consistent and rigorous

  3. Pyrrole-regulated precipitation of titania nanorods on polymer fabrics for photocatalytic degradation of trace toluene in air

    Science.gov (United States)

    Gu, Yi-Jie; Wen, Wei; Xu, Yang; Wu, Jin-Ming

    2018-03-01

    When compared with nanoparticulate counterparts, TiO2 thin films with vertically aligned one-dimensional (1D) nanostructures exhibit enhanced photocatalytic activity because of the highly accessible surface area. The perpendicular of the 1D nanostructure reduces the charge migration path and hence the carrier recombination rate, which also contributes to the photocatalytic activity. Furthermore, TiO2 thin films on flexible substrates are more suitable to degrade pollutants in either water or air because of its easy recovery and free-bending shape. In this study, flexible polyethylene fabrics were firstly coated with a sol-gel nanoparticulate TiO2 seed layer. Quasi-aligned TiO2 nanorods were then precipitated homogeneously under an atmospheric pressure and a low temperature not exceeding 80 °C, using a peroxy-titanium complex precursor with the additive of pyrrole. It is found that the density of TiO2 nanorods increased with the increasing amount of pyrrole monomers. The resultant TiO2 film on polyethylene fabrics exhibited a much reduced band gap of ca. 2.86 eV, which can be attributed to the surface oxygen deficiencies. When utilized to assist photocatalytic degradation of trace toluene in air under the UV light illumination, the TiO2 film exhibited a gradually increased photocatalytic activity upon the increasing cycles for up to six, because of the gradual removal of trace organics on the TiO2 surface. The highest photocatalytic efficiency is recorded to be 5 times that of TiO2 nanotube arrays, which are regarded as an excellent photocatalyst for air cleaning.

  4. Influence on sensitivity to insecticides: a case study of a settled area ...

    African Journals Online (AJOL)

    monitoring for successful alternative insecticides. There are currently two ... behaviour or modification avoid landing on insecticide .... aquarium fish food18. When they .... National Statistical Office (NSO) Malawi Government 1998 Census. 16.

  5. Mechanistic modeling of insecticide risks to breeding birds in North American agroecosystems

    Science.gov (United States)

    Insecticide usage in the United States is ubiquitous in urban, suburban, and rural environments. In evaluating data for an insecticide registration application and for registration review, scientists at the United States Environmental Protection Agency (USEPA) assess the fate of ...

  6. Influence of Pyrethroid Insecticides on Sodium and Calcium Influx in Neocortical Neurons

    Science.gov (United States)

    Pyrethroid insecticides bind to voltage-gated sodium channels and modify their gating kinetics, thereby disrupting neuronal function. Using murine neocortical neurons in primary culture, we have compared the ability of 11 structurally diverse pyrethroid insecticides to evoke Na+ ...

  7. Efficacy of an insecticide paint against insecticide-susceptible and resistant mosquitoes - Part 1: Laboratory evaluation

    Directory of Open Access Journals (Sweden)

    Carnevale Pierre

    2010-11-01

    Full Text Available Abstract Background The main malaria vector Anopheles gambiae and the urban pest nuisance Culex quinquefasciatus are increasingly resistant to pyrethroids in many African countries. There is a need for new products and strategies. Insecticide paint Inesfly 5A IGR™, containing two organophosphates (OPs, chlorpyrifos and diazinon, and insect growth regulator (IGR, pyriproxyfen, was tested under laboratory conditions for 12 months following WHOPES Phase I procedures. Methods Mosquitoes used were laboratory strains of Cx. quinquefasciatus susceptible and resistant to OPs. The paint was applied at two different doses (1 kg/6 m2 and 1 kg/12 m2 on different commonly used surfaces: porous (cement and stucco and non-porous (softwood and hard plastic. Insecticide efficacy was studied in terms of delayed mortality using 30-minute WHO bioassay cones. IGR efficacy on fecundity, fertility and larval development was studied on OP-resistant females exposed for 30 minutes to cement treated and control surfaces. Results After treatment, delayed mortality was high (87-100% even against OP-resistant females on all surfaces except cement treated at 1 kg/12 m2. Remarkably, one year after treatment delayed mortality was 93-100% against OP-resistant females on non-porous surfaces at both doses. On cement, death rates were low 12 months after treatment regardless of the dose and the resistance status. Fecundity, fertility and adult emergence were reduced after treatment even at the lower dose (p -3. A reduction in fecundity was still observed nine months after treatment at both doses (p -3 and adult emergence was reduced at the higher dose (p -3. Conclusions High mortality rates were observed against laboratory strains of the pest mosquito Cx. quinquefasciatus susceptible and resistant to insecticides. Long-term killing remained equally important on non-porous surfaces regardless the resistance status for over 12 months. The paint's effect on fecundity, fertility and

  8. 2-[2-(Aziridin-1-ylethyl]-5,5-dimethyl-2,5-dihydro-4H-benzo [e]isoindol-4-one (Cytotoxic Oxonaphthalene-Pyrroles, Part IV

    Directory of Open Access Journals (Sweden)

    Helmut Spreitzer

    2012-10-01

    Full Text Available An aziridine-containing side chain is attached to an oxonaphthalene-annelated pyrrole in expectation of DNA alkylating properties. The cytotoxicity is evaluated against two cell lines, KB-31 and KB-8511, respectively.

  9. Insecticide Usage and Chemical Contamination Assessment in Asiatic Pennywort

    Science.gov (United States)

    Bumroongsook, S.

    2017-07-01

    The insecticide usage in commercially grown asiatic pennywort plantations in Nakhonpatum and Nonthaburi province, Thailand was surveyed during January-June, 2016. The results showed that asiatic pennywort cuttworms was leaf destructive and caused the most damge to the production. The growers used organophosphate insecticides to control the caterpillars the most, followed by pyrethoid, abamectin, carbamate and organochlorine, respectively. The chemical contaminants of pennywort from 9 fresh markets in Bangkok was monitored, the result indicated that lead was not detected in the samples. The amount of arsenic was less than 0.075 mg / kg. The insecticide residue measurement of dicofol, chlorpyrifos and methidathion was 0.98, 2.84 and 0.46 mg / kg, respectively.

  10. Insecticide resistance in the western flower thrips, Frankliniella occidentalis

    DEFF Research Database (Denmark)

    Jensen, Sten Erik

    of acetylcholinesterase, the target site enzyme for methiocarb. The results from bioassays with synergists included indicated involvement of cytochrome P450- monooxygenases and esterases in methiocarb resistance in the most resistant populations. Selection with methiocarb on one of the populations to increase the level......The western flower thrips, Frankliniella occidentalis (Pergande) is a serious pest on a wide range of crops throughout the world. In Denmark F. occidentalis is a pest in greenhouses. F. occidentalis is difficult to control with insecticides because of its thigmokinetic behaviour and resistance...... to insecticides. Since F. occidentulis spread to become a worldwide pest in 1980’es, resistance to a number of different insecticides has been shown in many populations of F. occidentalis. This flower thrips has the potential of fast development of resistance owing to the short generation time, high fecundity...

  11. POTENTIATION OF COPAÍBA OIL-RESIN WITH SYNTHETIC INSECTICIDES TO CONTROL OF FALL ARMYWORM

    OpenAIRE

    ALMEIDA, WALDIANE ARAÚJO DE; SILVA, IGOR HONORATO LEDUÍNO DA; SANTOS, ANA CLÁUDIA VIEIRA DOS; BARROS JÚNIOR, AURÉLIO PAES; SOUSA, ADALBERTO HIPÓLITO DE

    2017-01-01

    ABSTRACT The control of Spodoptera frugiperda (J. E. SMITH) (Lepidoptera: Noctuidae) has been carried out mainly with pyrethroids and organophosphates insecticides. The continuous and indiscriminate use of synthetic insecticides, for decades, has led to the selection of resistant populations and has caused concerns for human health and the environment. An alternative is the use of botanical insecticides, including through the mixtures with synthetic insecticides. This study aimed to investiga...

  12. Optimal Cotton Insecticide Application Termination Timing: A Meta-Analysis.

    Science.gov (United States)

    Griffin, T W; Zapata, S D

    2016-08-01

    The concept of insecticide termination timing is generally accepted among cotton (Gossypium hirsutum) researchers; however, exact timings are often disputed. Specifically, there is uncertainty regarding the last economic insecticide application to control fruit-feeding pests including tarnished plant bug (Lygus lineolaris (Palisot de Beauvois)), boll weevil (Anthonomus grandis), bollworm (Helicoverpa zea), tobacco budworm (Heliothis virescens), and cotton fleahopper (Pseudatomoscelis seriatus). A systematic review of prior studies was conducted within a meta-analytic framework. Nine publicly available articles were amalgamated to develop an optimal timing principle. These prior studies reported 53 independent multiple means comparison field experiments for a total of 247 trial observations. Stochastic plateau theory integrated with econometric meta-analysis methodology was applied to the meta-database to determine the shape of the functional form of both the agronomic optimal insecticide termination timing and corresponding yield potential. Results indicated that current university insecticide termination timing recommendations are later than overall estimated timing suggested. The estimated 159 heat units (HU) after the fifth position above white flower (NAWF5) was found to be statistically different than the 194 HU termination used as the status quo recommended termination timing. Insecticides applied after 159 HU may have been applied in excess, resulting in unnecessary economic and environmental costs. Empirical results also suggested that extending the insecticide termination time by one unit resulted in a cotton lint yield increase of 0.27 kilograms per hectare up to the timing where the plateau began. Based on economic analyses, profit-maximizing producers may cease application as soon as 124 HU after NAWF5. These results provided insights useful to improve production systems by applying inputs only when benefits were expected to be in excess of the

  13. Insecticide resistance in vector Chagas disease: evolution, mechanisms and management.

    Science.gov (United States)

    Mougabure-Cueto, Gastón; Picollo, María Inés

    2015-09-01

    Chagas disease is a chronic parasitic infection restricted to America. The disease is caused by the protozoa Trypanosoma cruzi, which is transmitted to human through the feces of infected triatomine insects. Because no treatment is available for the chronic forms of the disease, vector chemical control represents the best way to reduce the incidence of the disease. Chemical control has been based principally on spraying dwellings with insecticide formulations and led to the reduction of triatomine distribution and consequent interruption of disease transmission in several areas from endemic region. However, in the last decade it has been repeatedly reported the presence triatomnes, mainly Triatoma infestans, after spraying with pyrethroid insecticides, which was associated to evolution to insecticide resistance. In this paper the evolution of insecticide resistance in triatomines is reviewed. The insecticide resistance was detected in 1970s in Rhodnius prolixus and 1990s in R. prolixus and T. infestans, but not until the 2000s resistance to pyrthroids in T. infestans associated to control failures was described in Argentina and Bolivia. The main resistance mechanisms (i.e. enhanced metabolism, altered site of action and reduced penetration) were described in the T. infestans resistant to pyrethrods. Different resistant profiles were demonstrated suggesting independent origin of the different resistant foci of Argentina and Bolivia. The deltamethrin resistance in T. infestans was showed to be controlled by semi-dominant, autosomally inherited factors. Reproductive and developmental costs were also demonstrated for the resistant T. infestans. A discussion about resistance and tolerance concepts and the persistence of T. infestans in Gran Chaco region are presented. In addition, theoretical concepts related to toxicological, evolutionary and ecological aspects of insecticide resistance are discussed in order to understand the particular scenario of pyrethroid

  14. Field and Laboratory Evaluations of Insecticides for Southern Pine Beetle Control

    Science.gov (United States)

    Felton L. Hastings; Jack E. Coster; [Editors

    1981-01-01

    Reports results of laboratory screenings and field studies of insecticides for use against the southern pine beetle. Preventive as webas remedial efficacywere observed, along with phytotoxicity to pine and understory hardwood species, effects of insecticides on soil microbial and mesofaunal populations, and degradation of insecticides by selected soil microbes.

  15. Pollution Of Insecticide Residues In PPTN Pasar Jumat Area

    International Nuclear Information System (INIS)

    Syahrir, Ulfa T.; Chairul, Sofnie M.

    2000-01-01

    Measurement of insecticide residue pollution from some organochlorin and organo-phosphat in soil and water samples were carried out 1999-2000 periode. The aim of the measurement was to get information about impact of laboratorium activity on insecticide contents in PPTN PASAR JUMAT. Gas chromatograph with electron capture and flame ionization detector were used to measure the pesticide content. Result of the measurement in PPTN area showed that organo-chlorin were alpha BHC, endosulfan band DDT and organo-phosphat were klorphyriphos and malation and were lower than tolerance level

  16. Characterizing the insecticide resistance of Anopheles gambiae in Mali.

    Science.gov (United States)

    Cisse, Moussa B M; Keita, Chitan; Dicko, Abdourhamane; Dengela, Dereje; Coleman, Jane; Lucas, Bradford; Mihigo, Jules; Sadou, Aboubacar; Belemvire, Allison; George, Kristen; Fornadel, Christen; Beach, Raymond

    2015-08-22

    The impact of indoor residual spraying (IRS) and long-lasting insecticide nets (LLINs), key components of the national malaria control strategy of Mali, is threatened by vector insecticide resistance. The objective of this study was to assess the level of insecticide resistance in Anopheles gambiae sensu lato populations from Mali against four classes of insecticide recommended for IRS: organochlorines (OCs), pyrethroids (PYs), carbamates (CAs) and organophosphates (OPs). Characterization of resistance was done in 13 sites across southern Mali and assessed presence and distribution of physiological mechanisms that included target-site modifications: knockdown resistance (kdr) and altered acetycholinesterase (AChE), and/or metabolic mechanisms: elevated esterases, glutathione S-transferases (GSTs), and monooxygenases. The World Health Organization (WHO) tube test was used to determine phenotypic resistance of An. gambiae s.l. to: dichlorodiphenyltrichloroethane (DDT) (OC), deltamethrin (PY), lambda-cyhalothrin (PY), bendiocarb (CA), and fenitrothion (OP). Identification of sibling species and presence of the ace-1 (R) and Leu-Phe kdr, resistance-associated mutations, were determined using polymerase chain reaction (PCR) technology. Biochemical assays were conducted to detect increased activity of GSTs, oxidases and esterases. Populations tested showed high levels of resistance to DDT in all 13 sites, as well as increased resistance to deltamethrin and lambda-cyhalothrin in 12 out of 13 sites. Resistance to fenitrothion and bendiocarb was detected in 1 and 4 out of 13 sites, respectively. Anopheles coluzzii, An. gambiae sensu stricto and Anopheles arabiensis were identified with high allelic frequencies of kdr in all sites where each of the species were found (13, 12 and 10 sites, respectively). Relatively low allelic frequencies of ace-1 (R) were detected in four sites where this assessment was conducted. Evidence of elevated insecticide metabolism, based on oxidase

  17. Insecticide applications to soil contribute to the development of Burkholderia mediating insecticide resistance in stinkbugs.

    Science.gov (United States)

    Tago, Kanako; Kikuchi, Yoshitomo; Nakaoka, Sinji; Katsuyama, Chie; Hayatsu, Masahito

    2015-07-01

    Some soil Burkholderia strains are capable of degrading the organophosphorus insecticide, fenitrothion, and establish symbiosis with stinkbugs, making the host insects fenitrothion-resistant. However, the ecology of the symbiotic degrading Burkholderia adapting to fenitrothion in the free-living environment is unknown. We hypothesized that fenitrothion applications affect the dynamics of fenitrothion-degrading Burkholderia, thereby controlling the transmission of symbiotic degrading Burkholderia from the soil to stinkbugs. We investigated changes in the density and diversity of culturable Burkholderia (i.e. symbiotic and nonsymbiotic fenitrothion degraders and nondegraders) in fenitrothion-treated soil using microcosms. During the incubation with five applications of pesticide, the density of the degraders increased from less than the detection limit to around 10(6)/g of soil. The number of dominant species among the degraders declined with the increasing density of degraders; eventually, one species predominated. This process can be explained according to the competitive exclusion principle using V(max) and K(m) values for fenitrothion metabolism by the degraders. We performed a phylogenetic analysis of representative strains isolated from the microcosms and evaluated their ability to establish symbiosis with the stinkbug Riptortus pedestris. The strains that established symbiosis with R. pedestris were assigned to a cluster including symbionts commonly isolated from stinkbugs. The strains outside the cluster could not necessarily associate with the host. The degraders in the cluster predominated during the initial phase of degrader dynamics in the soil. Therefore, only a few applications of fenitrothion could allow symbiotic degraders to associate with their hosts and may cause the emergence of symbiont-mediated insecticide resistance. © 2015 John Wiley & Sons Ltd.

  18. Role of cytochrome P450s in insecticide resistance: impact on the control of mosquito-borne diseases and use of insecticides on Earth.

    Science.gov (United States)

    David, Jean-Philippe; Ismail, Hanafy Mahmoud; Chandor-Proust, Alexia; Paine, Mark John Ingraham

    2013-02-19

    The fight against diseases spread by mosquitoes and other insects has enormous environmental, economic and social consequences. Chemical insecticides remain the first line of defence but the control of diseases, especially malaria and dengue fever, is being increasingly undermined by insecticide resistance. Mosquitoes have a large repertoire of P450s (over 100 genes). By pinpointing the key enzymes associated with insecticide resistance we can begin to develop new tools to aid the implementation of control interventions and reduce their environmental impact on Earth. Recent technological advances are helping us to build a functional profile of the P450 determinants of insecticide metabolic resistance in mosquitoes. Alongside, the cross-responses of mosquito P450s to insecticides and pollutants are also being investigated. Such research will provide the means to produce diagnostic tools for early detection of P450s linked to resistance. It will also enable the design of new insecticides with optimized efficacy in different environments.

  19. Post Hartree–Fock and DFT Studies on Pyrrole···Nitrogen and Pyrrole···Carbon Monoxide Molecules

    Directory of Open Access Journals (Sweden)

    P. Kolandaivel

    2002-07-01

    Full Text Available Abstract: The hydrogen bonded and van der Waals isomers of pyrrole···nitrogen and pyrrole···carbon monoxide have been studied using ab initio and density functional theory methods. Complex geometries and total energies of the isomers have been determined at HF, MP2, B3LYP and B3PW91 levels of theory employing 6-31G* basis set. For pyrrole···nitrogen complex, only two isomers have stable structure and the more stable one is found to be the hydrogen bonded isomer. Among the five isomers of pyrrole···carbon monoxide complex, the hydrogen bonded isomer is found to be the most stable form. The interaction energy for all these isomers have been calculated after eliminating the basis set superposition errors by using the full counterpoise correction method. Chemical hardness, chemical potential have been calculated and are used to study the stability of the molecules.

  20. Ferrocene-Functionalized 4-(2,5-Di(thiophen-2-yl-1H-pyrrol-1-ylaniline: A Novel Design in Conducting Polymer-Based Electrochemical Biosensors

    Directory of Open Access Journals (Sweden)

    Rukiye Ayranci

    2015-01-01

    Full Text Available Herein, we report a novel ferrocenyldithiophosphonate functional conducting polymer and its use as an immobilization matrix in amperometric biosensor applications. Initially, 4-(2,5-di(thiophen-2-yl-1H-pyrrol-1-ylamidoferrocenyldithiophosphonate was synthesized and copolymerized with 4-(2,5-di(thiophen-2-yl-1H-pyrrol-1-ylbenzenamine at graphite electrodes. The amino groups on the polymer were utilized for covalent attachment of the enzyme glucose oxidase. Besides, ferrocene on the backbone was used as a redox mediator during the electrochemical measurements. Prior to the analytical characterization, optimization studies were carried out. The changes in current signals at +0.45 V were proportional to glucose concentration from 0.5 to 5.0 mM. Finally, the resulting biosensor was applied for glucose analysis in real samples and the data were compared with the spectrophotometric Trinder method.

  1. 3-(Dicyanomethylidene)indan-1-one-Functionalized Calix[4]arene-Calix[4]pyrrole Hybrid: An Ion-Pair Sensor for Cesium Salts.

    Science.gov (United States)

    Yeon, Yerim; Leem, Soojung; Wagen, Corin; Lynch, Vincent M; Kim, Sung Kuk; Sessler, Jonathan L

    2016-09-02

    A chromogenic calix[4]arene-calix[4]pyrrole hybrid ion pair receptor bearing an indane substituent at a β-pyrrolic position has been prepared. On the basis of solution-phase UV-vis spectroscopic analysis and (1)H NMR spectroscopic studies carried out in 10% methanol in chloroform, receptor 1 is able to bind only cesium ion pairs (e.g., CsF, CsCl, and CsNO3) but not the constituent cesium cation (as its perchlorate salt) or the F(-), Cl(-), or NO3(-) anions (as the tetrabutylammonium salts). It thus displays rudimentary AND logic gate behavior. Receptor 1 shows a colorimetric response to cesium ion pairs under conditions of solid-liquid (nitrobenzene) and liquid-liquid (D2O-nitrobenzene-d5) extraction.

  2. Silica sulfuric acid: a reusable solid catalyst for one pot synthesis of densely substituted pyrrole-fused isocoumarins under solvent-free conditions

    Directory of Open Access Journals (Sweden)

    Sudipta Pathak

    2013-11-01

    Full Text Available A convenient and efficient methodology for the synthesis of densely substituted pyrrole-fused isocoumarins, which employs solid-supported silica sulfuric acid (SSA as catalyst, has been developed. When the mixture of ninhydrin adducts of acetylacetone/ethyl acetoacetate and primary amines was heated on the solid surface of SSA under solvent-free conditions, the pyrrole-fused isocoumarins were formed in good yields. This synthetic method has several advantages such as the employment of solvent-free reaction conditions without the use of any toxic reagents and metal catalysts, the ease of product isolation, the use of a recyclable catalyst, the low cost, the easy availability of the starting materials, and the excellent yields of products.

  3. Role of cytochrome P450s in insecticide resistance: impact on the control of mosquito-borne diseases and use of insecticides on Earth

    OpenAIRE

    David, Jean-Philippe; Ismail, Hanafy Mahmoud; Chandor-Proust, Alexia; Paine, Mark John Ingraham

    2013-01-01

    The fight against diseases spread by mosquitoes and other insects has enormous environmental, economic and social consequences. Chemical insecticides remain the first line of defence but the control of diseases, especially malaria and dengue fever, is being increasingly undermined by insecticide resistance. Mosquitoes have a large repertoire of P450s (over 100 genes). By pinpointing the key enzymes associated with insecticide resistance we can begin to develop new tools to aid the implementat...

  4. Insecticidal Potential of an Orally Administered Metabolic Extract of ...

    African Journals Online (AJOL)

    The insecticidal activity of Aspergillus niger IHCS-4 metabolic extract against Chrysomya chloropyga larvae was examined in vitro. The toxicity test revealed that 0.04 mg/g and 0.08 mg/g extract concentration significantly (P>0.05) affected the insect larvae, inducing 20% and 65% mortality respectively, within 24 hours.

  5. Effectiveness of plant based insecticides as a sustainable means of ...

    African Journals Online (AJOL)

    Cucumber (Cucumis sativus) is an important crop in Pakistan. It is affected by many biotic and abiotic factors. Among these, Cucumber mosaic virus is the important disease with economic losses. The purpose of this study was to evaluate the effectiveness of plant based insecticides as a sustainable means to control the ...

  6. Studies .on the efficacy of some biorational insecticides against the ...

    African Journals Online (AJOL)

    W. Tin znara*, C. Na11kinga, l Kashaija & W. Tu.vhemereirwe ... Biorat!onal insecticides obtained from tobacco, ash, urine, pepper and a concoction (mixture) were ... Cultural control ... single components were made by adding I 00 ml of tap.

  7. Risk of transmission of viral haemorrhagic fevers and the insecticide ...

    African Journals Online (AJOL)

    ... of transmission of viral haemorrhagic fevers and the insecticide susceptibility status of Ae. aegypti in some sites in Accra, Ghana. Design: Larval surveys were carried to inspect containers within households and estimate larval indices and adult Aedes mosquitoes were collected using human landing collection technique.

  8. The comparative insecticidal and residual efficacy of sniper and ...

    African Journals Online (AJOL)

    Otoigiakih

    Chemical control is still the main approach for urban pest control (Castle et al., 1999; Rozendaal, 1997; Marrs,. 1993; Lee and Yap, 2003; Tidwell et al., 1994). The use of insecticides is seen as the most effective tool in cockroach control program (WHO, 1996; Chavasse and. Yap, 1997; Lee and Yap, 2003; Tidwell et al., ...

  9. Susceptibility of Adult Mosquitoes to Insecticides in Aqueous Sucrose Baits

    Science.gov (United States)

    2011-06-01

    Lee, and A.H. Azahari. 2005. Adult and larval insecticide susceptibility status of Culex quinquefasciatus (Say) mosquitoes in Kuala Lumpur Malaysia ...Trop. Biomed. 22: 63-68. Nayar, J.K. and D.M. Sauerman, Jr. 1971. The effects of diet on life-span, fecundity and flight potential of Aedes

  10. Efficacy of some synthetic insecticides for control of cotton bollworms ...

    African Journals Online (AJOL)

    ... and Betsulfan at 3.2 l ha-1 recorded the highest and lowest yields, respectively. For effective control of cotton bollworms for maximum yield in the ecology, Thionex applied at 2.8 l ha-1 is recommended. Keywords: Control, cotton bollworms, efficacy, Ghana, synthetic insecticides. African Crop Science Journal, Vol. 20, No.

  11. Insecticide use and practices among cotton farmers in northern ...

    African Journals Online (AJOL)

    Cotton (Gossypium hirsutum L.) is an important cash crop in Uganda. Insecticide application practices among cotton growers in northern Uganda were examined to determine the pests targeted and the compliance of control measures with the standards recommended by the Uganda's Cotton Development Organization ...

  12. Pyrethroid insecticides in urban salmon streams of the Pacific Northwest

    Energy Technology Data Exchange (ETDEWEB)

    Weston, D.P., E-mail: dweston@berkeley.edu [Department of Integrative Biology, University of California, 3060 Valley Life Sciences Bldg., Berkeley, CA 94720-3140 (United States); Asbell, A.M., E-mail: aasbell@berkeley.edu [Department of Integrative Biology, University of California, 3060 Valley Life Sciences Bldg., Berkeley, CA 94720-3140 (United States); Hecht, S.A., E-mail: scott.hecht@noaa.gov [NOAA Fisheries, Office of Protected Resources, 510 Desmond Drive S.E., Lacey, WA 98503 (United States); Scholz, N.L., E-mail: nathaniel.scholz@noaa.gov [NOAA Fisheries, Northwest Fisheries Science Center, 2725 Montlake Blvd. E., Seattle, WA 98112 (United States); Lydy, M.J., E-mail: mlydy@siu.edu [Fisheries and Illinois Aquaculture Center and Department of Zoology, Southern Illinois University, 171 Life Sciences II, Carbondale, IL 62901 (United States)

    2011-10-15

    Urban streams of the Pacific Northwest provide spawning and rearing habitat for a variety of salmon species, and food availability for developing salmon could be adversely affected by pesticide residues in these waterbodies. Sediments from Oregon and Washington streams were sampled to determine if current-use pyrethroid insecticides from residential neighborhoods were reaching aquatic habitats, and if they were at concentrations acutely toxic to sensitive invertebrates. Approximately one-third of the 35 sediment samples contained measurable pyrethroids. Bifenthrin was the pyrethroid of greatest concern with regards to aquatic life toxicity, consistent with prior studies elsewhere. Toxicity to Hyalella azteca and/or Chironomus dilutus was found in two sediment samples at standard testing temperature (23 deg. C), and in one additional sample at a more environmentally realistic temperature (13 deg. C). Given the temperature dependency of pyrethroid toxicity, low temperatures typical of northwest streams can increase the potential for toxicity above that indicated by standard testing protocols. - Highlights: > Salmon-bearing creeks can be adversely impacted by insecticides from urban runoff. > Pyrethroid insecticides were found in one-third of the creeks in Washington and Oregon. > Two creeks contained concentrations acutely lethal to sensitive invertebrates. > Bifenthrin was of greatest concern, though less than in prior studies. > Standard toxicity testing underestimates the ecological risk of pyrethroids. - Pyrethroid insecticides are present in sediments of urban creeks of Oregon and Washington, though less commonly than in studies elsewhere in the U.S.

  13. Pyrethroid insecticides in urban salmon streams of the Pacific Northwest

    International Nuclear Information System (INIS)

    Weston, D.P.; Asbell, A.M.; Hecht, S.A.; Scholz, N.L.; Lydy, M.J.

    2011-01-01

    Urban streams of the Pacific Northwest provide spawning and rearing habitat for a variety of salmon species, and food availability for developing salmon could be adversely affected by pesticide residues in these waterbodies. Sediments from Oregon and Washington streams were sampled to determine if current-use pyrethroid insecticides from residential neighborhoods were reaching aquatic habitats, and if they were at concentrations acutely toxic to sensitive invertebrates. Approximately one-third of the 35 sediment samples contained measurable pyrethroids. Bifenthrin was the pyrethroid of greatest concern with regards to aquatic life toxicity, consistent with prior studies elsewhere. Toxicity to Hyalella azteca and/or Chironomus dilutus was found in two sediment samples at standard testing temperature (23 deg. C), and in one additional sample at a more environmentally realistic temperature (13 deg. C). Given the temperature dependency of pyrethroid toxicity, low temperatures typical of northwest streams can increase the potential for toxicity above that indicated by standard testing protocols. - Highlights: → Salmon-bearing creeks can be adversely impacted by insecticides from urban runoff. → Pyrethroid insecticides were found in one-third of the creeks in Washington and Oregon. → Two creeks contained concentrations acutely lethal to sensitive invertebrates. → Bifenthrin was of greatest concern, though less than in prior studies. → Standard toxicity testing underestimates the ecological risk of pyrethroids. - Pyrethroid insecticides are present in sediments of urban creeks of Oregon and Washington, though less commonly than in studies elsewhere in the U.S.

  14. Metaflumizone is a novel sodium channel blocker insecticide.

    Science.gov (United States)

    Salgado, V L; Hayashi, J H

    2007-12-15

    Metaflumizone is a novel semicarbazone insecticide, derived chemically from the pyrazoline sodium channel blocker insecticides (SCBIs) discovered at Philips-Duphar in the early 1970s, but with greatly improved mammalian safety. This paper describes studies confirming that the insecticidal action of metaflumizone is due to the state-dependent blockage of sodium channels. Larvae of the moth Spodoptera eridania injected with metaflumizone became paralyzed, concomitant with blockage of all nerve activity. Furthermore, tonic firing of abdominal stretch receptor organs from Spodoptera frugiperda was blocked by metaflumizone applied in the bath, consistent with the block of voltage-dependent sodium channels. Studies on native sodium channels, in primary-cultured neurons isolated from the CNS of the larvae of the moth Manduca sexta and on Para/TipE sodium channels heterologously expressed in Xenopus (African clawed frog) oocytes, confirmed that metaflumizone blocks sodium channels by binding selectively to the slow-inactivated state, which is characteristic of the SCBIs. The results confirm that metaflumizone is a novel sodium channel blocker insecticide.

  15. Insecticide resistance testing in malaria vectors in Tanzania ...

    African Journals Online (AJOL)

    mosquito survived much better and the scientists had a total of 467 mosquitoes to run the insecticide susceptibility tests. Innovative ways are necessary under field conditions for mosquito breeding in susceptibility studies. Key words: Malaria, Anopheles gambiae complex, larvae, fabric, resistance, susceptibility, Tanzania.

  16. Effective utilization period of long-lasting insecticide treated nets ...

    African Journals Online (AJOL)

    The study was conducted to evaluate the bioefficacy of long-lasting insecticide treated nets (LLITNs) (PermaNet®2.0) over time and the species composition of Anopheles mosquitoes around Bahir Dar. The space spray collection method was used to determine the species composition of indoor resting Anopheles ...

  17. Insecticide resistance and glutathione S-transferases in mosquitoes ...

    African Journals Online (AJOL)

    Mosquito glutathione S-transferases (GSTs) have received considerable attention in the last 20 years because of their role in insecticide metabolism producing resistance. Many different compounds, including toxic xenobiotics and reactive products of intracellular processes such as lipid peroxidation, act as GST substrates.

  18. Larvicidal, pupicidal and insecticidal activities of Cosmos bipinnatus ...

    African Journals Online (AJOL)

    Purpose: To evaluate the larvicidal, pupicidal and insecticidal activities of Cosmos bipinnatus, Foenuculum vulgare and Tagetes minuta leaf extracts against Culex quinquefasciatus mosquitoes. Methods: The leaves of the plants were extracted with distilled water, ethanol (95 %), and hexane and the extracts screened for ...

  19. Effect of natural and chemical insecticides on Hyalopterus pruni and ...

    African Journals Online (AJOL)

    Experiments were carried out to evaluate the effect of water extracts of Fagonia arabica, Salix alba and Anthmis pseudocotula and their mixtures with chemical insecticide (Malathion) on growth of. Hyalopterus pruni and characters of Armeniaca vulgaris plants and their soils. The data revealed that F.arabica extract at 20% ...

  20. Biological efficacy of the ecotoxically favourable insecticides and ...

    African Journals Online (AJOL)

    The high biologic efficacy, mechanism of action, resistance to water rinsing, high selectivity, and small quantities of application, anticipated a bright future for them. Since results of researches of biological efficacy of insecticides in laboratory and field conditions are statistically different, studies done in natural conditions ...

  1. Insecticide assays against the brown stink bug feeding on pecan

    Science.gov (United States)

    The brown stink bug, Euschistus servus (Say) (Hemiptera: Pentatomidae), is an economic pest of pecan, Carya illinoinensis (Wangenh) K. Koch (Juglandaceae), and other agronomic crops across the southeastern U.S. Management of this pest is mainly via insecticides. Many commercial products indicate o...

  2. Environmental insecticide residues from tsetse fly control measures in Uganda

    International Nuclear Information System (INIS)

    Sserunjoji-Sebalija, J.

    1976-01-01

    Up to June 1974 areas in Uganda totalling 8600km 2 have been successfully reclaimed from tsetse fly infestation by ground spray of 3% dieldrin water emulsions. A search for equally effective but less persistent and toxic compounds against tsetse flies has been unsuccessful. Fourteen insecticide formulations have been tested for their persistence on tree bark surfaces and, therefore, their availability and toxicity to the target tsetse flies. Only those compounds with a high immediate insecticidal activity (some higher than dieldrin) like endosulfan, Chlorfenvinphos and propoxur could merit further consideration in tsetse control. While some were toxic to tsetse as fresh deposits, they lacked sufficient persistence. A study of the environmental implication from the continued use of the highly persistent and toxic dieldrin has provided useful data on residues likely to be found both in terrestrial and aquatic fauna and flora. These are generally low. Moreover, there is evidence of degradation in some fish species (Protopterus aethiopicus and Clarias). Also, dilution factors and adsorption involving the muddy nature of water run-off, etc., and controlled burning of grasses after tsetse eradication would tend to inactivate the residual insecticide and protect aquatic systems. The general findings have indicated less risk than anticipated of the environmental contamination from tsetse control by application of persistent and toxic insecticides. (author)

  3. Ethnobotany of plants used as insecticides, repellents and ...

    African Journals Online (AJOL)

    An ethnobotanical study on plants used for the prevention and treatment of malaria was conducted to document the indigenous knowledge particularly associated with the use and conservation of anti-malarial, insecticide and insect repellent medicinal plants. In this study, five sampling sites were selected based on the ...

  4. Chemical Composition and Insecticidal Activity of the Essential Oil of ...

    African Journals Online (AJOL)

    Purpose: To investigate the chemical composition and insecticidal activity of the essential oil of the aerial parts of Ostericum grosseserratum against the maize weevil, Sitophilus zeamaisD. Methods: Steam distillation of the aerial parts of O. grosseserratum during the flowering stage was carried out using a Clavenger ...

  5. Chemical composition and insecticidal properties of essential oil ...

    African Journals Online (AJOL)

    Purpose: To determine the insecticidal properties of essential oil from Mosla soochowensis aerial parts against two insect pests, Sitophilus zeamais and Tribolium castaneum. Methods: Hydro-distillation of M. soochowensis was used to extract the essential oil. Gas chromatography/mass spectrometry (GC/MS) analysis was ...

  6. Bio-insecticides and mating disruption in cranberries

    Science.gov (United States)

    Surveys of native entomopathogenic nematodes in Wisconsin have produced a new bio-insecticide involving two particular nematode species (Oscheius onirici and Heterorhabditis georgiana). In field studies, these nematodes have shown high virulence against flea beetles; in the laboratory, these nematod...

  7. Insecticide Use Practices in Cocoa Production in Four Regions in ...

    African Journals Online (AJOL)

    Most of the insecticides used are classified as class II under WHO Hazard category, and the farmers used very minimal protective clothing during pesticides application. The results of this study show that there is the need to intensify education on safe handling and use of pesticides to reduce pesticide abuse, especially by ...

  8. Cytotoxic effects of delfin insecticide (Bacillus thuringiensis) on cell ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-08-04

    Aug 4, 2008 ... In acute exposure cells showed deformities such as swelling of cells, oval shaped deformity, and ... Commercial grade of delfin insecticide used in this study was manufactured by .... exposure to cigarette extracts. Antibiotics caused .... administration of a neem pesticide on rat metabolic enzymes. J. Environ.

  9. Material gain: bednets treated with insecticides improve the lives of ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2011-07-15

    ... 700 mosquito nets each day, marketed under brand names such as "Health Net" and ... Material gain: bednets treated with insecticides improve the lives of Tanzanians. July 15, 2011. Image ... The kit is one of the key elements of PSI's Social Marketing of ... The national strategy will work to change this by involving the full ...

  10. Flupyradifurone: a brief profile of a new butenolide insecticide

    Science.gov (United States)

    Nauen, Ralf; Jeschke, Peter; Velten, Robert; Beck, Michael E; Ebbinghaus-Kintscher, Ulrich; Thielert, Wolfgang; Wölfel, Katharina; Haas, Matthias; Kunz, Klaus; Raupach, Georg

    2015-01-01

    BACKGROUND The development and commercialisation of new chemical classes of insecticides for efficient crop protection measures against destructive invertebrate pests is of utmost importance to overcome resistance issues and to secure sustainable crop yields. Flupyradifurone introduced here is the first representative of the novel butenolide class of insecticides active against various sucking pests and showing an excellent safety profile. RESULTS The discovery of flupyradifurone was inspired by the butenolide scaffold in naturally occurring stemofoline. Flupyradifurone acts reversibly as an agonist on insect nicotinic acetylcholine receptors but is structurally different from known agonists, as shown by chemical similarity analysis. It shows a fast action on a broad range of sucking pests, as demonstrated in laboratory bioassays, and exhibits excellent field efficacy on a number of crops with different application methods, including foliar, soil, seed treatment and drip irrigation. It is readily taken up by plants and translocated in the xylem, as demonstrated by phosphor imaging analysis. Flupyradifurone is active on resistant pests, including cotton whiteflies, and is not metabolised by recombinantly expressed CYP6CM1, a cytochrome P450 conferring metabolic resistance to neonicotinoids and pymetrozine. CONCLUSION The novel butenolide insecticide flupyradifurone shows unique properties and will become a new tool for integrated pest management around the globe, as demonstrated by its insecticidal, ecotoxicological and safety profile. © 2014 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:25351824

  11. Seed coating with a neonicotinoid insecticide negatively affects wild bees.

    Science.gov (United States)

    Rundlöf, Maj; Andersson, Georg K S; Bommarco, Riccardo; Fries, Ingemar; Hederström, Veronica; Herbertsson, Lina; Jonsson, Ove; Klatt, Björn K; Pedersen, Thorsten R; Yourstone, Johanna; Smith, Henrik G

    2015-05-07

    Understanding the effects of neonicotinoid insecticides on bees is vital because of reported declines in bee diversity and distribution and the crucial role bees have as pollinators in ecosystems and agriculture. Neonicotinoids are suspected to pose an unacceptable risk to bees, partly because of their systemic uptake in plants, and the European Union has therefore introduced a moratorium on three neonicotinoids as seed coatings in flowering crops that attract bees. The moratorium has been criticized for being based on weak evidence, particularly because effects have mostly been measured on bees that have been artificially fed neonicotinoids. Thus, the key question is how neonicotinoids influence bees, and wild bees in particular, in real-world agricultural landscapes. Here we show that a commonly used insecticide seed coating in a flowering crop can have serious consequences for wild bees. In a study with replicated and matched landscapes, we found that seed coating with Elado, an insecticide containing a combination of the neonicotinoid clothianidin and the non-systemic pyrethroid β-cyfluthrin, applied to oilseed rape seeds, reduced wild bee density, solitary bee nesting, and bumblebee colony growth and reproduction under field conditions. Hence, such insecticidal use can pose a substantial risk to wild bees in agricultural landscapes, and the contribution of pesticides to the global decline of wild bees may have been underestimated. The lack of a significant response in honeybee colonies suggests that reported pesticide effects on honeybees cannot always be extrapolated to wild bees.

  12. Grafting of palladium nanoparticles onto mesoporous molecular sieve MCM-41: Heterogeneous catalysts for the formation of an N-substituted pyrrol

    Czech Academy of Sciences Publication Activity Database

    Demel, Jan; Čejka, Jiří; Bakardjieva, Snejana; Štěpnička, P.

    2007-01-01

    Roč. 263, 1-2 (2007), s. 259-265 ISSN 1381-1169 R&D Projects: GA ČR GA104/05/0192; GA MŠk(CZ) LC06070 Institutional research plan: CEZ:AV0Z40400503; CEZ:AV0Z40320502 Keywords : palladium * nanoparticles * MCM-41 * pyrrol * catalysis Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.707, year: 2007

  13. Electrochromic properties of multicolored novel polymer synthesized via combination of benzotriazole and N-functionalized 2,5-di(2-thienyl)-1H-pyrrole units

    International Nuclear Information System (INIS)

    Rende, Eda; Kilic, Cihan E.; Udum, Yasemin Arslan; Toffoli, Daniele; Toppare, Levent

    2014-01-01

    Synthesis of new conducting polymers is desired since their electrochemical and optical properties enable them to be used as active layers in many device applications. Benzotriazole and N-functionalized 2,5-di(2-thienyl)-1H-pyrrole (SNS Series) containing polymers showed very promising results as electrochromic materials. In order to observe the effect of the combination of these two units, three new monomers; 2-(6-(2,5-bis(5-methylthiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-di (thiophen-2-yl)-2H benzo[d][1,2,3]triazole (M1), 2-(6-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-di(thiophen-2-yl) -2H-benzo[d][1,2,3]triazole (M2) and 2-(6-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)hexyl)-4,7-bis (5-methylthiophen-2-yl)-2H-benzo[d][1,2,3]triazole (M3) were synthesized. To better characterize the electronic and spectroscopic properties of the monomers, density functional theory (DFT) and its time-dependent generalization (TD-DFT) were used to calculate their vertical ionization potentials, vertical electron affinity and to simulate and interpret their infrared and UV-vis spectra. The monomers were electrochemically polymerized and the resultant polymers were characterized with cyclic voltammetry and UV-vis-NIR spectroscopy techniques. An electrochromic device was constructed with electrochemical polymer of M2. The device switched between red and blue colors and showed exceptional optical memory

  14. meso-Octamethylcalix[4]pyrrole as an effective macrocyclic receptor for the univalent thallium cation in the gas phase: Experimental and theoretical study

    Czech Academy of Sciences Publication Activity Database

    Polášek, Miroslav; Makrlík, E.; Kvíčala, J.; Křížová, Věra; Vaňura, P.

    Roč. 1153 ( 2018 ), s. 78-84 ISSN 0022-2860 R&D Projects: GA MŠk CZ.1.05/3.2.00/08.0144 Grant - others:GA MŠk(CZ) 20/2015; GA MŠk(CZ) LM2010005 Institutional support: RVO:61388955 Keywords : Thallium cation * meso-Octamethylcalix[4]pyrrole * Complexation * DFT calculations * Structures Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.753, year: 2016

  15. Autoassemblage de macromolécules biologiques via des poly(pyrroles) et/ou des nanotubes de carbone fonctionnalisés

    OpenAIRE

    Baur , Jessica

    2010-01-01

    This work is dedicated to the development of hybrid assemblies based on polymers and biomolecules with or without carbon nanotubes with the aim to show their applications in different areas such as biosensors or bio-fuel cells. Firstly, poly(pyrrole-NTA)/Cu2+ was used for the elaboration of DNA or enzymatic biosensors. So, it was able to be used with its affinity partner, histidine, for the reversible immobilization of oligonucleotide probes tagged with histidines. Thanks to a detection witho...

  16. Novel and viable acetylcholinesterase target site for developing effective and environmentally safe insecticides.

    Science.gov (United States)

    Pang, Yuan-Ping; Brimijoin, Stephen; Ragsdale, David W; Zhu, Kun Yan; Suranyi, Robert

    2012-04-01

    Insect pests are responsible for human suffering and financial losses worldwide. New and environmentally safe insecticides are urgently needed to cope with these serious problems. Resistance to current insecticides has resulted in a resurgence of insect pests, and growing concerns about insecticide toxicity to humans discourage the use of insecticides for pest control. The small market for insecticides has hampered insecticide development; however, advances in genomics and structural genomics offer new opportunities to develop insecticides that are less dependent on the insecticide market. This review summarizes the literature data that support the hypothesis that an insect-specific cysteine residue located at the opening of the acetylcholinesterase active site is a promising target site for developing new insecticides with reduced off-target toxicity and low propensity for insect resistance. These data are used to discuss the differences between targeting the insect-specific cysteine residue and targeting the ubiquitous catalytic serine residue of acetylcholinesterase from the perspective of reducing off-target toxicity and insect resistance. Also discussed is the prospect of developing cysteine-targeting anticholinesterases as effective and environmentally safe insecticides for control of disease vectors, crop damage, and residential insect pests within the financial confines of the present insecticide market.

  17. Antitumor Activity of a 5-Hydroxy-1H-Pyrrol-2-(5H-One-Based Synthetic Small Molecule In Vitro and In Vivo.

    Directory of Open Access Journals (Sweden)

    Yunyun Geng

    Full Text Available Alternative chemo-reagents are in great demand because chemotherapy resistance is one of the major challenges in current cancer treatment. 5-hydoxy-1H-pyrrol-2-(5H-one is an important N-heterocyclic scaffold that is present in natural products and medicinal chemistry. However, its antitumor activity has not been systematically explored. In this study, we screened a panel of 5-hydoxy-1H-pyrrol-2-(5H-one derivatives and identified compound 1d as possessing strong anti-proliferative activity in multiple cancer cell lines. Cell cycle analysis revealed that 1d can induce S-phase cell cycle arrest and that HCT116 was sensitive to 1d-induced apoptosis. Further analysis indicated that 1d preferentially induced DNA damage and p53 activation in HCT116 cells and that 1d-induced apoptosis is partly dependent on p53. Furthermore, we showed that 1d significantly suppressed tumor growth in xenograft tumor models in vivo. Taken together, our results suggest that 5-hydoxy-1H-pyrrol-2-(5H-one derivatives bear potential antitumor activity and that 1d is an effective agent for cancer treatment.

  18. Biological alterations and self-reported symptoms among insecticides-exposed workers in Burkina Faso.

    Science.gov (United States)

    Toe, Adama M; Ilboudo, Sylvain; Ouedraogo, Moustapha; Guissou, Pierre I

    2012-03-01

    Occupationally exposed workers, farm workers and plant protection agents in the Sahel region of Burkina Faso were interviewed to assess adverse health effects of insecticides. The subjects were also examined for changes in both hematological and biochemical parameters. The prevalence of liver and kidney dysfunction was found to be quite high among insecticide applicators, especially among plant protection agents. The prevalence of biochemical alterations seems to be correlated to the frequency of insecticide use. However, no significant differences were found between the hematological parameters among farm workers and plant protection agents. The hematological parameters of all the insecticide applicators were normal. The great majority of insecticide applicators (85%) reported symptoms related to insecticide exposure. The use of insecticides in the agriculture of Burkina Faso is threatening to human health.

  19. Toxicity of some insecticides to the haemocytes of giant honeybee, Apis dorsata F. under laboratory conditions

    Directory of Open Access Journals (Sweden)

    Nighat Perveen

    2017-07-01

    Full Text Available Quantitative studies concerning total and differential haemocyte counts and abnormalities were performed under laboratory conditions for larvae, pupae and adults collected from a wild Apis dorsata colony. Haemolymph samples were observed immediately, thirty and sixty minutes after field recommended concentration exposure of five different insecticides. Total haemocyte counts were significantly higher for larvae and pupae but less for adult bees, however, differential haemocyte counts insignificantly different. Exposure of insecticides showed variable response for tested insecticides with immediate increased change with ethofenprox, diafenthiuron and imidacloprid but decreased for all tested insecticides after sixty minutes. For differential haemocyte counts, plasmatocytes and granulocytes increased with exposure of insecticides. Immune response of haemocytes against insecticides showed different degrees of abnormalities like agglutination, denucleation and cell shape distortion. Such studies may help in possible identification of insect defense mechanisms against their exposure to external hazards for instance insecticide exposure.

  20. Radiation fixation of vinyl chloride in an insecticide aerosol container

    International Nuclear Information System (INIS)

    Kagiya, V.T.; Takemoto, K.

    1975-01-01

    Recently, a large quantity of vinyl chloride has been used as spraying additive for insecticide aerosols. Since January 1974 when the Food and Drug Administration of the United States of America announced that vinyl chloride causes liver cancer, it has been forbidden in Japan and the United States of America to market insecticide aerosol containers containing vinyl chloride. In Japan, following a government order, about 20 million insecticide aerosol containers have been collected and put into storage. A report is given on the radiation fixation of vinyl chloride as polyvinylchloride powder by gamma-ray-induced polymerization in the aerosol container. Insecticide aerosol containers containing vinyl chloride were irradiated by gamma rays from 60 Co at room temperature. Vinyl chloride polymerized to form powdered polymer in the container. Polymerization conversion increased with the irradiation dose, and after 10 Mrad irradiation, vinyl chloride was not found in the sprayed gas. This establishes that vinyl chloride can be fixed by gamma-ray irradiation in the aerosol container. To accelerate the reaction rate, the effect of various additives on the reaction was investigated. It was found that halogenated hydrocarbons, such as chloroform and carbon tetrachloride, accelerated the initiation of the polymerization, and that a vinyl monomer such as vinyl acetate accelerated the reaction rate due to the promotion of the initiation and the high reactivity of the polyvinylacetate radical to vinyl chloride. Consequently, the required irradiation dose for the fixation of vinyl chloride was decreased to less than 5 Mrad by the addition of various kinds of additives. Following the request of the Ministry of Public Welfare, various technical problems for large-scale treatment are being studied with the co-operation of the Federation of Insecticide Aerosols. (author)

  1. Agricultural insecticides threaten surface waters at the global scale.

    Science.gov (United States)

    Stehle, Sebastian; Schulz, Ralf

    2015-05-05

    Compared with nutrient levels and habitat degradation, the importance of agricultural pesticides in surface water may have been underestimated due to a lack of comprehensive quantitative analysis. Increasing pesticide contamination results in decreasing regional aquatic biodiversity, i.e., macroinvertebrate family richness is reduced by ∼30% at pesticide concentrations equaling the legally accepted regulatory threshold levels (RTLs). This study provides a comprehensive metaanalysis of 838 peer-reviewed studies (>2,500 sites in 73 countries) that evaluates, for the first time to our knowledge on a global scale, the exposure of surface waters to particularly toxic agricultural insecticides. We tested whether measured insecticide concentrations (MICs; i.e., quantified insecticide concentrations) exceed their RTLs and how risks depend on insecticide development over time and stringency of environmental regulation. Our analysis reveals that MICs occur rarely (i.e., an estimated 97.4% of analyses conducted found no MICs) and there is a complete lack of scientific monitoring data for ∼90% of global cropland. Most importantly, of the 11,300 MICs, 52.4% (5,915 cases; 68.5% of the sites) exceeded the RTL for either surface water (RTLSW) or sediments. Thus, the biological integrity of global water resources is at a substantial risk. RTLSW exceedances depend on the catchment size, sampling regime, and sampling date; are significantly higher for newer-generation insecticides (i.e., pyrethroids); and are high even in countries with stringent environmental regulations. These results suggest the need for worldwide improvements to current pesticide regulations and agricultural pesticide application practices and for intensified research efforts on the presence and effects of pesticides under real-world conditions.

  2. Insecticide resistance status of Aedes aegypti (L.) from Colombia.

    Science.gov (United States)

    Fonseca-González, Idalyd; Quiñones, Martha L; Lenhart, Audrey; Brogdon, William G

    2011-04-01

    To evaluate the insecticide susceptibility status of Aedes aegypti (L.) in Colombia, and as part of the National Network of Insecticide Resistance Surveillance, 12 mosquito populations were assessed for resistance to pyrethroids, organophosphates and DDT. Bioassays were performed using WHO and CDC methodologies. The underlying resistance mechanisms were investigated through biochemical assays and RT-PCR. All mosquito populations were susceptible to malathion, deltamethrin and cyfluthrin, and highly resistant to DDT and etofenprox. Resistance to lambda-cyhalothrin, permethrin and fenitrothion ranged from moderate to high in some populations from Chocó and Putumayo states. In Antioquia state, the Santa Fe population was resistant to fenitrothion. Biochemical assays showed high levels of both cytochrome P450 monooxygenases (CYP) and non-specific esterases (NSE) in some of the fenitrothion- and pyrethroid-resistant populations. All populations showed high levels of glutathione-S-transferase (GST) activity. GSTe2 gene was found overexpressed in DDT-resistant populations compared with Rockefeller susceptible strain. Differences in insecticide resistance status were observed between insecticides and localities. Although the biochemical assay results suggest that CYP and NSE could play an important role in the pyrethroid and fenitrothion resistance detected, other mechanisms remain to be investigated, including knockdown resistance. Resistance to DDT was high in all populations, and GST activity is probably the main enzymatic mechanism associated with this resistance. The results of this study provide baseline data on insecticide resistance in Colombian A. aegypti populations, and will allow comparison of changes in susceptibility status in this vector over time. Copyright © 2011 Society of Chemical Industry.

  3. Underpinning sustainable vector control through informed insecticide resistance management.

    Directory of Open Access Journals (Sweden)

    Edward K Thomsen

    Full Text Available There has been rapid scale-up of malaria vector control in the last ten years. Both of the primary control strategies, long-lasting pyrethroid treated nets and indoor residual spraying, rely on the use of a limited number of insecticides. Insecticide resistance, as measured by bioassay, has rapidly increased in prevalence and has come to the forefront as an issue that needs to be addressed to maintain the sustainability of malaria control and the drive to elimination. Zambia's programme reported high levels of resistance to the insecticides it used in 2010, and, as a result, increased its investment in resistance monitoring to support informed resistance management decisions.A country-wide survey on insecticide resistance in Zambian malaria vectors was performed using WHO bioassays to detect resistant phenotypes. Molecular techniques were used to detect target-site mutations and microarray to detect metabolic resistance mechanisms. Anopheles gambiae s.s. was resistant to pyrethroids, DDT and carbamates, with potential organophosphate resistance in one population. The resistant phenotypes were conferred by both target-site and metabolic mechanisms. Anopheles funestus s.s. was largely resistant to pyrethroids and carbamates, with potential resistance to DDT in two locations. The resistant phenotypes were conferred by elevated levels of cytochrome p450s.Currently, the Zambia National Malaria Control Centre is using these results to inform their vector control strategy. The methods employed here can serve as a template to all malaria-endemic countries striving to create a sustainable insecticide resistance management plan.

  4. Interaction of derived polymers from pyrrole with biocompatible solutions; Interaccion de polimeros derivados de pirrol con soluciones biocompatibles

    Energy Technology Data Exchange (ETDEWEB)

    Lopez G, O. G.

    2010-07-01

    This work presents a study about the synthesis by plasma, the electric properties and superficial interaction of polymers derived from pyrrole doped with Iodine with potential use as bio material. Poly-pyrrole is a semiconductor and biocompatible polymer with potential application in the development of artificial muscles and implants where the electric interaction between cells and material is an important variable. The syntheses were made at 13.5 MHz in a glass tubular reactor of 1500 cm{sup 3} with electrodes of 6.5 cm diameter and stainless steel flanges. An electrode was connected to the RF terminal of the power supply that is combined with a matching coupling resistance. The monomer and dopant used in this work were pyrrole and Iodine respectively, in closed containers. They were vaporized and injected separately into the reactor at room temperature and 0.1 mbar. The vapors of the reagents mixed freely in the reactor. The synthesis time was 240 min at 40, 60, 80 and 100 W. The polymers were obtained as thin films adhered to the reactor walls. The films were washed and swollen with distilled water and removed from the reactor walls with a small spatula. The polymers were irradiated with gamma rays at 18 and 22 KGy. Due to the fact that the doses are cumulative, the final dose applied was 40 KGy. The polymers characterization was carried out by Fourier Transform Infrared Spectroscopy, thermogravimetric analysis (TGA), scanning electron microscopy, contact angle, electrical conductivity and X-ray diffraction. The analyses indicates that the polymers have very similar structure in almost the entire power range, showing C-O, C=C, C-H, O-H, N-H bonds with a predominantly amorphous structure. The TGA analyses showed that the material has 4 or 5 loses of material. The first one starts after that 115 C except for the material irradiated at 40 KGy, this one begins in 87 C, the second one is in the interval of 196 and 295 C, the third one between 311 and 500 C, and the

  5. Ferricyanide confined into the integrative system of pyrrolic surfactant and SWCNTs: The enhanced electrochemial sensing of paracetamol

    International Nuclear Information System (INIS)

    Wu, Xiao-Yan; Niu, Wen-Jun; Cosnier, Serge; Deng, Sheng-Yuan; Zhang, Xue-Ji; Shan, Dan

    2015-01-01

    Highlights: • Amphiphilic surfactant derived from pyrrole was used to construct a special microheterogeneous system incorporated with SWCNTs by electropolymerization. • Common redox probe, Fe(CN) 6 3−/4− , was captured into this microheterogeneous system due to the cooperation interactions of electrostatic and π-π stacking. • A dramatically negative shift in the half wave potential compared to Fe(CN) 6 3−/4− in aqueous solution can be obtained due to the unusual Fe(CN) 6 3−/4− partitioning. • The entrapped Fe(CN) 6 3−/4− was applied in the construction of the enhanced electrochemical sensor to paracetamol. - Abstract: An enhanced paracetamol sensor was developed based on the integrative system of single walled carbon nanotubes (SWCNTs) and the pyrrolic surfactant, (11-pyrrolyl-1-yl-undecyl)triethylammonium tetrafluoroborate (A 2 ), in which confined the redox probe, Fe(CN) 6 3−/4− . A well-defined redox peaks of the firmly confined Fe(CN) 6 3−/4− with dramatically negative shift in the half-wave potential compared to Fe(CN) 6 3−/4− in aqueous solution was observed at GCE/polyA 2 -Fe(CN) 6 3−/4− /SWCNTs. To understand the unusual Fe(CN) 6 3−/4− partitioning in this microheterogeneous system, the responses of the Fe(CN) 6 3−/4− at the electrodes modified by SWCNTs, polyA 2 , SWCNTs/polyA 2 , and polyA 2 /SWCNTs were investigated, respectively. The results of cyclic voltammetry (CV) and differential pulse voltammetry (DPV) indicated that the proposed electrode exhibiting efficient electrocatalytic capability towards the paracetamol oxidation. Thereafter, an amperometric assay for paracetamol at GCE/polyA 2 -Fe(CN) 6 3−/4− /SWCNTs was developed at 0.4 V with an enhanced linear range from 3.4×10 −7 ∼7.98 × 10 −4 M.

  6. Biofabrication Using Pyrrole Electropolymerization for the Immobilization of Glucose Oxidase and Lactate Oxidase on Implanted Microfabricated Biotransducers

    Directory of Open Access Journals (Sweden)

    Christian N. Kotanen

    2014-03-01

    Full Text Available The dual responsive Electrochemical Cell-on-a-Chip Microdisc Electrode Array (ECC MDEA 5037 is a recently developed electrochemical transducer for use in a wireless, implantable biosensor system for the continuous measurement of interstitial glucose and lactate. Fabrication of the biorecognition membrane via pyrrole electropolymerization and both in vitro and in vivo characterization of the resulting biotransducer is described. The influence of EDC-NHS covalent conjugation of glucose oxidase with 4-(3-pyrrolyl butyric acid (monomerization and with 4-sulfobenzoic acid (sulfonization on biosensor performance was examined. As the extent of enzyme conjugation was increased sensitivity decreased for monomerized enzymes but increased for sulfonized enzymes. Implanted biotransducers were examined in a Sprague-Dawley rat hemorrhage model. Resection after 4 h and subsequent in vitro re-characterization showed a decreased sensitivity from 0.68 (±0.40 to 0.22 (±0.17 µA·cm−2·mM−1, an increase in the limit of detection from 0.05 (±0.03 to 0.27 (±0.27 mM and a six-fold increase in the response time from 41 (±18 to 244 (±193 s. This evidence reconfirms the importance of biofouling at the bio-abio interface and the need for mitigation strategies to address the foreign body response.

  7. Effect of non-electroactive additives on the early stage pyrrole electropolymerization on indium tin oxide electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Castro-Beltran, A. [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ave. Pedro de Alba s/n, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Centro de Innovación Investigación y Desarrollo en Ingeniería y Tecnología (CIIDIT), Universidad Autónoma de Nuevo León, PIIT-Monterrey C.P. 66600 Apodaca, N.L. (Mexico); Dominguez, C.; Bahena-Uribe, D. [Centro Investigación en Ingeniería y Ciencias Aplicadas (CIICAp), Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, C.P. 62209 Cuernavaca, Mor. (Mexico); Sepulveda-Guzman, S., E-mail: selene.sepulvedagz@uanl.edu.mx [Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León, Ave. Pedro de Alba s/n, Ciudad Universitaria, C.P. 66451 San Nicolás de los Garza, N.L. (Mexico); Centro de Innovación Investigación y Desarrollo en Ingeniería y Tecnología (CIIDIT), Universidad Autónoma de Nuevo León, PIIT-Monterrey C.P. 66600 Apodaca, N.L. (Mexico); Cruz-Silva, R. [Research Center for Exotic NanoCarbon, Shinshu University, 4-17-1 Wakasato, Nagano 380-8553 (Japan)

    2014-09-01

    The use of non-electroactive additives during electrodeposition of conducting polymers has long been used to modify the properties of deposited films. These additives can improve the adhesion, and not only change the morphology and deposition rate but also modify the chemical composition of the electrodeposited polymer. Several compounds have been used to modify deposition of polypyrrole; however, there is no systematic study of these compounds. In this work, we comparatively studied several water soluble chemical compounds, a cationic polymer, an anionic polymer, a cationic surfactant, and an anionic surfactant during potentiostatic electrodeposition of polypyrrole. In order to study the effect of these compounds on the interface, where the electrochemical polymerization takes place, we used electrochemical impedance spectroscopy. The morphology during the initial stage of growth was studied by atomic force microscopy, whereas the resulting polypyrrole films were observed by scanning electron microscopy. - Highlights: • Early-stage polymerization polypyrrole particles on indium tin oxide (ITO). • Anionic additives promote pyrrole oxidation and polypyrrole film growth on ITO. • Cationic polyelectrolyte promotes adhesion between ITO and polypyrrole film. • Non-electroactive additives strongly influence polypyrrole nucleation on ITO.

  8. Quantitation of Pyrrole-Imidazole Polyamide in Rat Plasma by High-Performance Liquid Chromatography Coupled with UV Detection

    Directory of Open Access Journals (Sweden)

    Tomonori Kamei

    2012-01-01

    Full Text Available A simple and robust method using high-performance liquid chromatography with UV detection was developed and validated for the determination of six pyrrole-imidazole (PI polyamides (HN.49, TGF-β1f, TGF-β1t, HN.50f, HN.50t, and LOX-1 in rat plasma. After the plasma proteins were precipitated with methanol containing phenacetin as an internal standard, the analytes were separated on a Luna C18 (2 (5 μm, 4.6×150 mm. Calibration curves were linear over the range of 0.5 to 200 μg/mL for HN.49, 0.25 to 200 μg/mL for TGF-β1f, TGF-β1t, HN.50t, and LOX-1, 1 to 200 μg/mL for HN.50f in rat plasma. The inter- and intraday precision were below 15%, and the accuracy was within 15% at the quality controls. The validated method was successfully applied to sample analysis for the pharmacokinetic study.

  9. Characterization of electro-conductive fabrics prepared by in situ chemical and electrochemical polymerization of pyrrole onto polyester fabric

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Syamal; Das, Dipayan; Sen, Kushal, E-mail: kushal@textile.iitd.ernet.in

    2014-09-15

    Highlights: • Surface resistivity of the fabrics decreased rapidly with an increase in add-on. • Add-on and resistivity were not correlated below a resistivity value of about 200 Ω. • Higher add-on but lower surface roughness resulted in lower surface resistivity. • The voltage–current and voltage–temperature behaviours were found to be non-linear. • Electro-conductive fabric exhibited 98% electromagnetic shielding efficiency. - Abstract: This paper reports a study on electro-conductive fabrics prepared by a combined in situ chemical and electrochemical polymerization of pyrrole. Specific observations are made to establish the roles of add-on and surface roughness on the surface resistivity of the electro-conductive fabrics. The performance characteristics of the fabrics are reported in terms of electrical conductivity, voltage–current and voltage–temperature characteristics and electromagnetic interference (EMI) shielding capability. The surface resistivity of the fabric was found to be as low as 11.79 Ω. The voltage–current profile of the fabric is observed to be non-ohmic as well as the voltage–temperature curve is found to be exponential. The EMI shielding efficiency of the fabric was found to be about 98%.

  10. Electropolymerization of pyrrole on oxidizable metal under high frequency ultrasound irradiation. Application of focused beam to a selective masking technique

    Energy Technology Data Exchange (ETDEWEB)

    Et Taouil, A. [Institut UTINAM, UMR 6213 CNRS, Universite de Franche-Comte, 30 Avenue de l' observatoire, 25009 Besancon Cedex (France); Lallemand, F., E-mail: fabrice.lallemand@univ-fcomte.f [Institut UTINAM, UMR 6213 CNRS, Universite de Franche-Comte, 30 Avenue de l' observatoire, 25009 Besancon Cedex (France); Hallez, L.; Hihn, J-Y. [Institut UTINAM, UMR 6213 CNRS, Universite de Franche-Comte, 30 Avenue de l' observatoire, 25009 Besancon Cedex (France)

    2010-12-01

    A novel masking technique against polymer deposition based on High Intensity Focused Ultrasound (HIFU) irradiation was developed for the first time. With this in mind, a variety of background salts were tested. Sodium salicylate was found to be the most effective electrolytic medium for pyrrole sonoelectropolymerization on copper as it leads to a very efficient passivating oxide layer preventing copper dissolution while enabling polymer formation independently from sonication. In such a medium, high frequency ultrasound greatly refines surface structure, and a slight increase in doping level is observed. Finally, it was proved that focused ultrasound increases copper dissolution in sodium oxalate electrolyte while preventing polypyrrole deposition. A selected zone on the copper substrate was thus irradiated by the focused ultrasound beam to protect it from polymerization. In a second stage, a self-assembled monolayer was deposited on this polymer-free area to create a surface biphased substrate. This type of masking technique can be proposed as an interesting alternative to lithography as it is easier to carry out and allows chemical waste reduction.

  11. Characterization of poly pyrrole/montmorillonite electro polymerised onto Pt; Caracterizacao de filmes PPy/montmorilonita eletropolimerizados sobre Pt

    Energy Technology Data Exchange (ETDEWEB)

    Castagno, K.R.L., E-mail: katiarlc@pelotas.ifsul.edu.b [Instituto Federal Sul-rio-grandense (IFSul), RS (Brazil). Dept. de Quimica; Azambuja, D.S.; Dalmoro, V.; Mauller, R.S. [Universidade Federal do Rio Grande do Sul (UFRGS), Pelotas, RS (Brazil). Inst. de Quimica

    2010-07-01

    In this study films of polypyrrole/montmorillonite (PPy/MT) were electropolymerized on platinum in order to evaluate the performance of this technique in the preparation of nanocomposite materials and to determine the thermal properties and conductivity of the composites. The films were synthesized from a solution containing pyrrole, dodecylbenzene sulfonate, acid and two types of clays: montmorillonite-Na + (MT-Na) and montmorillonite-30B (MT-M). The characterization of the films we have used FT-IR, TEM, XRD, TGA, DSC and resistivity measurement by the four-point van der Pauw method. The study showed that the adopted method of exfoliation and the electropolymerization method used, allows obtaining nanocomposite materials. Analyses of FT-IR, TEM and XRD show that the clays are exfoliated in the polymer matrix. Thermal analysis of the films indicates that the addition of clay reflects an enhancement in the thermal properties of the matrix of PPy, but decreases the conductivity of the same. (author)

  12. Synthesis of Poly pyrrole Inverse Opal in [bmim] Containing Acetonitrile and the Application of the Inverse Opal in Cell Prototype

    International Nuclear Information System (INIS)

    Yan, W.; Dong, Q.Q.; Sun, L.N.; Deng, W.; Wu, Sh.

    2013-01-01

    Most primary cells use Zn or Li as the anode, a metallic oxide as the cathode, and an acidic or alkaline solution or moist past as the electrolytic solution. In this paper, highly ordered poly pyrrole (PPy) inverse opals have been successfully synthesized in the acetonitrile solution containing [bmim]PF 6 . PPy films were prepared under the same experimental conditions. Cyclic voltammograms of the PPy film and the PPy inverse opal in neutral phosphate buffer solution (PBS) were recorded. X-ray photoelectron spectroscopy technique was used to investigate the structural surface of the PPy films and the PPy inverse opals. It is found that the PF 6 - anions kept de doping from the PPy films during the potential scanning process, resulting in the electrochemical inactivity. Although PF 6 - anions also kept de doping from the PPy inverse opals, the PO 4 3- anions from PBS could dope into the inverse opal, explaining why the PPy inverse opals kept their electrochemical activity. An environmental friendly cell prototype was constructed, using the PPy inverse opal as the anode. The electrolytes in both the cathodic and anodic half-cells were neutral PBSs. The open-circuit potential of the cell prototype reached 0.487 V and showed a stable output over several hundred hours

  13. Sub-10 nm Platinum Nanocrystals with Size and Shape Control: Catalytic Study for Ethylene and Pyrrole Hydrogenation

    Energy Technology Data Exchange (ETDEWEB)

    Tsung, Chia-Kuang; Kuhn, John N.; Huang, Wenyu; Aliaga, Cesar; Hung, Ling-I; Somorjai, Gabor A.; Yang, Peidong

    2009-03-02

    Platinum nanocubes and nanopolyhedra with tunable size from 5 to 9 nm were synthesized by controlling the reducing rate of metal precursor ions in a one-pot polyol synthesis. A two-stage process is proposed for the simultaneous control of size and shape. In the first stage, the oxidation state of the metal ion precursors determined the nucleation rate and consequently the number of nuclei. The reaction temperature controlled the shape in the second stage by regulation of the growth kinetics. These well-defined nanocrystals were loaded into MCF-17 mesoporous silica for examination of catalytic properties. Pt loadings and dispersions of the supported catalysts were determined by elemental analysis (ICP-MS) and H2 chemisorption isotherms, respectively. Ethylene hydrogenation rates over the Pt nanocrystals were independent of both size and shape and comparable to Pt single crystals. For pyrrole hydrogenation, the nanocubes enhanced ring-opening ability and thus showed a higher selectivity to n-butylamine as compared to nanopolyhedra.

  14. Synthesis of 1-((4-methoxyphenyl-3-alkynes-1H-pyrrole-2,5-diones and functionalization to tria

    Directory of Open Access Journals (Sweden)

    Bakhat Ali

    2017-05-01

    Full Text Available A series of alkynyl maleimides were prepared via one-step cross-coupling reaction using bromomaleimide and acetylenes under the Sonogashira conditions, affording 1-((4-methoxyphenyl-3-alkynes-1H-pyrrole-2,5-diones in good to high yields. These products were subsequently converted in the corresponding 1,2,3-triazole using conventional click chemistry approach. The alkynyl maleimide compound (8g crystallized in the triclinic space group P1 with unit cell parameters a = 5.3692(6, b = 9.2513(10, c = 10.3070(11 Å, α = 85.349(4, β = 86.892(4, γ = 86.892(4°, V = 507.31(10 Å3, and Z = 1. In the crystal the molecules are stacked parallel to the c axis and held together through a C–H⋯π and a C–H⋯O interaction.

  15. Electrochemical characteristics of coated steel with poly(N-methyl pyrrole) synthesized in presence of ZnO nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoudian, M.R., E-mail: M_R_mahmoudian@yahoo.com [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Department of Chemistry, Masjed-Soleiman Branch, Islamic Azad University, Masjed-Soleiman (Iran, Islamic Republic of); Basirun, W.J.; Alias, Y. [Department of Chemistry, University of Malaya, Kuala Lumpur 50603 (Malaysia); Khorsand Zak, A. [Low Dimensional Materials Research Center, Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)

    2011-10-31

    Poly(N-methyl pyrrole) (PMPy) coating was electrodeposited on steel substrates in mixed electrolytes of dodecyl benzene sulphonic acid with oxalic acid in the absence and the presence of ZnO nanoparticles (NPs). The morphology and compositions were characterized by Field Emission Scanning Electron Microscopy (FESEM), Fourier Transform Infrared Spectroscopy and Energy-dispersive X-ray spectroscopy. Electrode/coating/electrolyte system was studied by Electrochemical Impedance Spectroscopy. The comparison between the pore resistance (R{sub po}) of synthesized PMPy in the absence and presence of ZnO NPs indicated that the existence of ZnO increased the R{sub po} of the coating. The FESEM micrographs indicated that the size of micro-spherical grains in the morphology of PMPy is significantly reduced and the surface area of PMPy is increased with the presence of ZnO NPs. The increase of the ability to interact with the ions liberated during the corrosion reaction of steel and the increase of the rate probability for the occurrence of cathodic reduction of oxygen on the PMPy with the increase of the surface area can be considered as reasons for improvement of protective properties of synthesized PMPy in the presence of ZnO NPs.

  16. Characterization of electro-conductive fabrics prepared by in situ chemical and electrochemical polymerization of pyrrole onto polyester fabric

    International Nuclear Information System (INIS)

    Maiti, Syamal; Das, Dipayan; Sen, Kushal

    2014-01-01

    Highlights: • Surface resistivity of the fabrics decreased rapidly with an increase in add-on. • Add-on and resistivity were not correlated below a resistivity value of about 200 Ω. • Higher add-on but lower surface roughness resulted in lower surface resistivity. • The voltage–current and voltage–temperature behaviours were found to be non-linear. • Electro-conductive fabric exhibited 98% electromagnetic shielding efficiency. - Abstract: This paper reports a study on electro-conductive fabrics prepared by a combined in situ chemical and electrochemical polymerization of pyrrole. Specific observations are made to establish the roles of add-on and surface roughness on the surface resistivity of the electro-conductive fabrics. The performance characteristics of the fabrics are reported in terms of electrical conductivity, voltage–current and voltage–temperature characteristics and electromagnetic interference (EMI) shielding capability. The surface resistivity of the fabric was found to be as low as 11.79 Ω. The voltage–current profile of the fabric is observed to be non-ohmic as well as the voltage–temperature curve is found to be exponential. The EMI shielding efficiency of the fabric was found to be about 98%

  17. An alternative laser driven photodissociation mechanism of pyrrole via πσ*1∕S0 conical intersection.

    Science.gov (United States)

    Nandipati, K R; Lan, Z; Singh, H; Mahapatra, S

    2017-06-07

    A first principles quantum dynamics study of N-H photodissociation of pyrrole on the S 0 - 1 πσ * (A21) coupled electronic states is carried out with the aid of an optimally designed UV-laser pulse. A new photodissociation path, as compared to the conventional barrier crossing on the πσ*1 state, opens up upon electronic transitions under the influence of pump-dump laser pulses, which efficiently populate both the dissociation channels. The interplay of electronic transitions due both to vibronic coupling and the laser pulse is observed in the control mechanism and discussed in detail. The proposed control mechanism seems to be robust, and not discussed in the literature so far, and is expected to trigger future experiments on the πσ*1 photochemistry of molecules of chemical and biological importance. The design of the optimal pulses and their application to enhance the overall dissociation probability is carried out within the framework of optimal control theory. The quantum dynamics of the system in the presence of pulse is treated by solving the time-dependent Schrödinger equation in the semi-classical dipole approximation.

  18. An alternative laser driven photodissociation mechanism of pyrrole via π*1σ/S0 conical intersection

    Science.gov (United States)

    Nandipati, K. R.; Lan, Z.; Singh, H.; Mahapatra, S.

    2017-06-01

    A first principles quantum dynamics study of N-H photodissociation of pyrrole on the S0-1π σ*(A12) coupled electronic states is carried out with the aid of an optimally designed UV-laser pulse. A new photodissociation path, as compared to the conventional barrier crossing on the π*1σ state, opens up upon electronic transitions under the influence of pump-dump laser pulses, which efficiently populate both the dissociation channels. The interplay of electronic transitions due both to vibronic coupling and the laser pulse is observed in the control mechanism and discussed in detail. The proposed control mechanism seems to be robust, and not discussed in the literature so far, and is expected to trigger future experiments on the π*1σ photochemistry of molecules of chemical and biological importance. The design of the optimal pulses and their application to enhance the overall dissociation probability is carried out within the framework of optimal control theory. The quantum dynamics of the system in the presence of pulse is treated by solving the time-dependent Schrödinger equation in the semi-classical dipole approximation.

  19. Preparation of thin α-particle sources using poly-pyrrole films functionalized by a chelating agent

    International Nuclear Information System (INIS)

    Mariet, C.

    2000-01-01

    This work takes place in the scope of analysis of the α-particle emitting elements U, Pu and Am present in compound environmental matrix like sols and sediments. The samples diversity and above all the α-ray characteristics require the analyst to implement a sequence of chemical steps in which the more restricting is the actinides concentration in a uniform and thin layer en allowing an accurately measure of alpha activity. On this account, we studied a new technique for radioactive sources preparation based on tow steps: preparation of a thin film as source support; incorporation of radioactive elements by a chelating extraction mechanism. The thin films were obtained through electro-polymerization of pyrrole monomer functionalized by an chelating ligand able to extract actinides from concentrated acidic solutions. Polymerization conditions of this monomer were perfected, then obtained films were characterized from a physico-chemical point of view. We point out their extracting properties were comparable to (retention capacity, distribution coefficient) to those of usual ion-exchange resins. The underscore of uranyl and americium nitrate complexes formed in the thin layer allowed to calculate the extraction constants in case acid extraction is negligible. Thanks to this results, the values of the coefficients distribution D U and D Am could be provided for all nitric solutions in which acid extraction is negligible. Optimal actinides retention conditions in the polymer were defined and used to settle a protocol for plutonium analysis in environmental samples. (author)

  20. Fe{sub 2}O{sub 3}-Poly-pyrrole hybrid nano-composite materials for super-capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Mallouki, M.; Tran-Van, F.; Sarrazin, C.; Chevrot, C. [Cergy-Pontoise Univ., Lab. de Physicochimie des Polymeres et des Interfaces (LPPI), EA 2528 95 (France); Fauvarque, J.F. [CNAM, Lab. d' Electrochimie Industrielle, 75 - Paris (France); Simon, P. [Universite Paul Sabatier, CIRIMAT-LCMIE, UMR 5085, 31 - Toulouse (France); De, A. [Saha Institute of Nuclear Physics, Calcutta (India)

    2004-07-01

    Fe{sub 2}O{sub 3}-Poly-pyrrole hybrid nano-composite materials chemically synthesized from colloid particles of iron oxide in aqueous solution have been processed to realize electrode materials for super-capacitor applications. The performances have been evaluated by cyclic voltammetry and galvano-static techniques in a three-electrode cell. The capacitance of Fe{sub 2}O{sub 3}-PPy hybrid nano-composite doped with para-toluene-sulfonate reaches 47 mAh/g in PC/NEt{sub 4}BF{sub 4} with a good stability during cycling (loss of 3% after 1000 cycles). Transmission Electronic Microscopy indicates a porous nano-structure with spherical particles in a range of 400-500 nm which ensures a good accessibility of the electrolyte in the bulk of the electro-active hybrid material. Preliminary studies with room temperature ionic liquid show promising results since the specific capacitance reaches 427 F/g in 1- ethyl-3-methyl-imidazolium bis((tri-fluoro-methyl)sulfonyl)amide (EMITFSI). (authors)

  1. Probabilistic risk assessment of insecticide concentrations in agricultural surface waters: a critical appraisal.

    Science.gov (United States)

    Stehle, Sebastian; Knäbel, Anja; Schulz, Ralf

    2013-08-01

    Due to the specific modes of action and application patterns of agricultural insecticides, the insecticide exposure of agricultural surface waters is characterized by infrequent and short-term insecticide concentration peaks of high ecotoxicological relevance with implications for both monitoring and risk assessment. Here, we apply several fixed-interval strategies and an event-based sampling strategy to two generalized and two realistic insecticide exposure patterns for typical agricultural streams derived from FOCUS exposure modeling using Monte Carlo simulations. Sampling based on regular intervals was found to be inadequate for the detection of transient insecticide concentrations, whereas event-triggered sampling successfully detected all exposure incidences at substantially lower analytical costs. Our study proves that probabilistic risk assessment (PRA) concepts in their present forms are not appropriate for a thorough evaluation of insecticide exposure. Despite claims that the PRA approach uses all available data to assess exposure and enhances risk assessment realism, we demonstrate that this concept is severely biased by the amount of insecticide concentrations below detection limits and therefore by the sampling designs. Moreover, actual insecticide exposure is of almost no relevance for PRA threshold level exceedance frequencies and consequential risk assessment outcomes. Therefore, we propose a concept that features a field-relevant ecological risk analysis of agricultural insecticide surface water exposure. Our study quantifies for the first time the environmental and economic consequences of inappropriate monitoring and risk assessment concepts used for the evaluation of short-term peak surface water pollutants such as insecticides.

  2. A potential target for organophosphate insecticides leading to spermatotoxicity.

    Science.gov (United States)

    Suzuki, Himiko; Tomizawa, Motohiro; Ito, Yuki; Abe, Keisuke; Noro, Yuki; Kamijima, Michihiro

    2013-10-16

    Organophosphate (OP) insecticides as an anticholinesterase also act on the diverse serine hydrolase targets, thereby revealing secondary or unexpected toxic effects including male reproductive toxicity. The present investigation detects a possible target molecule(s) for OP-induced spermatotoxicity (sperm deformity, underdevelopment, and reduced motility) from a chemical standpoint. The activity-based protein profiling (ABPP) approach with a phosphonofluoridate fluorescent probe pinpointed the molecular target for fenitrothion (FNT, a major OP insecticide) oxon (bioactive metabolite of FNT) in the mouse testicular membrane proteome, i.e., FNT oxon phosphorylates the fatty acid amide hydrolase (FAAH), which plays pivotal roles in spermatogenesis and sperm motility acquirement. Subsequently, mice were treated orally with vehicle or FNT for 10 days, and FAAH activity in testis or epididymis cauda was markedly reduced by the subacute exposure. ABPP analysis revealed that FAAH was selectively inhibited among the FNT-treated testicular membrane proteome. Accordingly, FAAH is a potential target for OP-elicited spermatotoxicity.

  3. Voltage-gated sodium channels as targets for pyrethroid insecticides.

    Science.gov (United States)

    Field, Linda M; Emyr Davies, T G; O'Reilly, Andrias O; Williamson, Martin S; Wallace, B A

    2017-10-01

    The pyrethroid insecticides are a very successful group of compounds that have been used extensively for the control of arthropod pests of agricultural crops and vectors of animal and human disease. Unfortunately, this has led to the development of resistance to the compounds in many species. The mode of action of pyrethroids is known to be via interactions with the voltage-gated sodium channel. Understanding how binding to the channel is affected by amino acid substitutions that give rise to resistance has helped to elucidate the mode of action of the compounds and the molecular basis of their selectivity for insects vs mammals and between insects and other arthropods. Modelling of the channel/pyrethroid interactions, coupled with the ability to express mutant channels in oocytes and study function, has led to knowledge of both how the channels function and potentially how to design novel insecticides with greater species selectivity.

  4. Synthesis and Insecticidal Activities of Novel Phthalic Acid Diamides

    Institute of Scientific and Technical Information of China (English)

    闫涛; 李玉新; 李永强; 王多义; 陈伟; 刘卓; 李正名

    2012-01-01

    In order to discover novel insecticides with the new action mode on ryanodine receptor (RyR), a series of novel phthalic acid diamide derivatives were designed and synthesized. All compounds were characterized by 1H NMR spectra and HRMS. The preliminary results of biological activity assessment indicated that some title compounds exhibited excellent insecticidal activities against Mythimna separata, Spodoptera exigua, and Plutella xylostella. The title compound 3-nitro-N-cyclopropyl-N'-[2-methyl-4-(perfluoropropan-2-yl)phenyl]phthalamidte (4a) was more efficient against diamondback moths than the control (chlorantraniliprole). The effects of some title compounds on intracellular calcium of neurons from the Spodoptera exigua proved that the title compounds were RyR activators.

  5. Sorption and desorption of insecticides in Brazilian soils

    International Nuclear Information System (INIS)

    Luchini, L.C.; Lord, K.A.; Ruegg, E.F.

    1980-01-01

    The sorption from aqueous solution of ten Brazilian soil types of four organochlorine, two organophosphorus and one carbamate insecticide was determined in the laboratory using gas chromatographic and radiometric techniques. Measurements showed that soils richest in organic matter, sorbed all substances except aldrin more strongly than the other soils. DDT was the most and aldrin the least sorbed organochlorine pesticide, being dieldrin sorbed two to four times more strongly than aldrin. Sorption of lindane varied in different soils. The organophosphate insecticides malathion and parathion were strongly sorbed in the soils richest in organic matter and weakly sorbed in the poorest soils heing moderately sorbed by the other soils. Sorption of carbaryl by all soils is small. Lindane was desorbed from the soil richest in organic matter and the extent of desorption was dependent on the sorption time. (Author) [pt

  6. Fipronil insecticide: novel photochemical desulfinylation with retention of neurotoxicity

    International Nuclear Information System (INIS)

    Hainzl, D.; Casida, J.E.

    1996-01-01

    Fipronil is an outstanding new insecticide for crop protection with good selectivity between insects and mammals. The insecticidal action involves blocking the gamma-aminobutyric acid-gated chloride channel with much greater sensitivity of this target in insects than in mammals. Fipronil contains a trifluoromethylsulfinyl moiety that is unique among the agrochemicals and therefore presumably important in its outstanding performance. We find that this substituent unexpectedly undergoes a novel and facile photoextrusion reaction on plants upon exposure to sunlight, yielding the corresponding trifluoromethylpyrazole, i.e., the desulfinyl derivative. The persistence of this photoproduct and its high neuroactivity, resulting from blocking the gamma-aminobutyric acid-gated chloride channel, suggest that it may be a significant contributor to the effectiveness of fipronil. In addition, desulfinylfipronil is not a metabolite in mammals, so the safety evaluations must take into account not only the parent compound but also this completely new environmental product

  7. The impact of insecticides to local honey bee colony Apis cerana indica in laboratory condition

    Science.gov (United States)

    Putra, Ramadhani E.; Permana, Agus D.; Nuriyah, Syayidah

    2014-03-01

    Heavy use of insecticides considered as one of common practice at local farming systems. Even though many Indonesian researchers had stated the possible detrimental effect of insecticide on agriculture environment and biodiversity, researches on this subject had been neglected. Therefore, our purpose in this research is observing the impact of insecticides usage by farmer to non target organisme like local honey bee (Apis cerana indica), which commonly kept in area near agriculture system. This research consisted of field observations out at Ciburial, Dago Pakar, Bandung and laboratory tests at School of Life Sciences and Technology, Institut Teknologi Bandung. The field observations recorded visited agriculture corps and types of pollen carried by bees to the nest while laboratory test recorderd the effect of common insecticide to mortality and behavior of honey bees. Three types of insecticides used in this research were insecticides A with active agent Chlorantraniliprol 50 g/l, insecticide B with active agent Profenofos 500 g/l, and insecticides C with active agent Chlorantraniliprol 100 g/l and λ-cyhalotrin 50g/l. The results show that during one week visit, wild flower, Wedelia montana, visited by most honey bees with average visit 60 honey bees followed by corn, Zea mays, with 21 honey bees. The most pollen carried by foragers was Wedelia montana, Calliandra callothyrsus, and Zea mays. Preference test show that honeybees tend move to flowers without insecticides as the preference to insecticides A was 12.5%, insecticides B was 0%, and insecticides was C 4.2%. Mortality test showed that insecticides A has LD50 value 0.01 μg/μl, insecticide B 0.31 μg/μl, and insecticides C 0.09 μg/μl which much lower than suggested dosage recommended by insecticides producer. This research conclude that the use of insecticide could lower the pollination service provide by honey bee due to low visitation rate to flowers and mortality of foraging bees.

  8. Insecticide susceptibility status of human biting mosquitoes in ...

    African Journals Online (AJOL)

    Matowo Pc

    91.5% (n=483) and An. funestus group was 8.5% (n=45). ..... Chitnis, N., Churcher, T., Donnelly, M.J., Ghani, A.C., Godfray, H.C.J., Gould, F., Hastings, ... Efficacy, persistence and vector susceptibility to pirimiphos-methyl (Actellic® 300CS) insecticide ... Macoris, M.L., Andrighetti, M.T.M., Wanderley, D.M.V. & Ribolla, P.E.M. ...

  9. A critical review of neonicotinoid insecticides for developmental neurotoxicity

    Science.gov (United States)

    Sheets, Larry P.; Li, Abby A.; Minnema, Daniel J.; Collier, Richard H.; Creek, Moire R.; Peffer, Richard C.

    2016-01-01

    Abstract A comprehensive review of published and previously unpublished studies was performed to evaluate the neonicotinoid insecticides for evidence of developmental neurotoxicity (DNT). These insecticides have favorable safety profiles, due to their preferential affinity for nicotinic receptor (nAChR) subtypes in insects, poor penetration of the mammalian blood–brain barrier, and low application rates. Nevertheless, examination of this issue is warranted, due to their insecticidal mode of action and potential exposure with agricultural and residential uses. This review identified in vitro, in vivo, and epidemiology studies in the literature and studies performed in rats in accordance with GLP standards and EPA guidelines with imidacloprid, acetamiprid, thiacloprid, clothianidin, thiamethoxam, and dinotefuran, which are all the neonicotinoids currently registered in major markets. For the guideline-based studies, treatment was administered via the diet or gavage to primiparous female rats at three dose levels, plus a vehicle control (≥20/dose level), from gestation day 0 or 6 to lactation day 21. F1 males and females were evaluated using measures of motor activity, acoustic startle response, cognition, brain morphometry, and neuropathology. The principal effects in F1 animals were associated with decreased body weight (delayed sexual maturation, decreased brain weight, and morphometric measurements) and acute toxicity (decreased activity during exposure) at high doses, without neuropathology or impaired cognition. No common effects were identified among the neonicotinoids that were consistent with DNT or the neurodevelopmental effects associated with nicotine. Findings at high doses were associated with evidence of systemic toxicity, which indicates that these insecticides do not selectively affect the developing nervous system. PMID:26513508

  10. Usage Possibilities of Insecticide Effective Biocidals in Organic Agriculture

    OpenAIRE

    Şimşek, Muharrem; Yağcı, Mürşide; Yaşarer, Haluk

    2016-01-01

    In conventional agriculture it is aimed that mainly increase in the amount of products, synthetic chemicals and fertilizers are used extensively to provide it. Today, terms such as safe food, human and environment health have become more important. Therefore, it is necessary to increase the share of organic agriculture which have less negative impacts to human health and environment, and sustainable use of natural resources. Herein environmentally insecticide effective biocidals to pest contr...

  11. Chemical Composition, Antifungal and Insecticidal Activities of Hedychium Essential Oils

    Science.gov (United States)

    2013-04-11

    Hedychiums have been reported to possess antibacterial, antifungal, and insecticidal activities [4,5]. Strawberry anthracnose, caused by the plant...pathogens Colletotrichum species is one of the most important diseases affecting strawberries worldwide [6]. Colletotrichum fragariae Brooks is most...often associated with anthracnose crown rot of strawberries grown in hot, humid areas such as the southeastern United States [7]. The azalea lace bug

  12. Cytochrome P450 monooxygenases and insecticide resistance in insects.

    OpenAIRE

    Bergé, J B; Feyereisen, R; Amichot, M

    1998-01-01

    Cytochrome P450 monooxygenases are involved in many cases of resistance of insects to insecticides. Resistance has long been associated with an increase in monooxygenase activities and with an increase in cytochrome P450 content. However, this increase does not always account for all of the resistance. In Drosophila melanogaster, we have shown that the overproduction of cytochrome P450 can be lost by the fly without a corresponding complete loss of resistance. These results prompted the seque...

  13. Culminating anti-malaria efforts at long lasting insecticidal net?

    Directory of Open Access Journals (Sweden)

    Sunil Dhiman

    2014-11-01

    Full Text Available Summary: Background: Long-lasting insecticidal nets (LLINs are a primary method in malaria control efforts. However, a decline in the biological efficacy and physical integrity over a period of comparatively lesser time than claimed, waning of naturally acquired immunity among regular users and misuse of LLINs are serious concerns. Search and selection of literature: The literature for the current review was searched in PubMed, SCOPUS Database and Google using combined search strings of related key-words. Literature with sufficient data and information on the current subject was selected to reach a valid conclusion. Findings: The World Health Organization (WHO has emphasized that LLINs should be considered a public good for people inhabiting malaria endemic settings. LLINs exhibited a cumulative effect on the vector density and may force anthropophilic mosquito vectors to find alternative animal hosts for blood meal. However, the physical integrity and biological activity of LLINs declines faster than the anticipated time due to different operational conditions and the spread of insecticide resistance. LLINs have been successful in reducing malaria incidences by either reducing or not allowing human exposure to the vector mosquitoes, but at the same time, LLINs debilitate the natural protective immunity against malaria parasite. Misuse of LLINs for deviant purposes is common and is a serious environmental concern, as people believe that traditional methods of prevention against malaria that have enabled them to survive through a long time are effective and sufficient. Moreover, people are often ill-informed regarding the toxic effects of LLINs. Conclusions: Specific criteria for determining the serviceable life and guidelines on the safe washing and disposal of LLINs need to be developed, kept well-informed and closely monitored. Malaria case management, environment management and community awareness to reduce the misuse of LLINs are crucial

  14. Chloride channels as tools for developing selective insecticides.

    Science.gov (United States)

    Bloomquist, Jeffrey R

    2003-12-01

    Ligand-gated chloride channels underlie inhibition in excitable membranes and are proven target sites for insecticides. The gamma-aminobutyric acid (GABA(1)) receptor/chloride ionophore complex is the primary site of action for a number of currently used insecticides, such as lindane, endosulfan, and fipronil. These compounds act as antagonists by stabilizing nonconducting conformations of the chloride channel. Blockage of the GABA-gated chloride channel reduces neuronal inhibition, which leads to hyperexcitation of the central nervous system, convulsions, and death. We recently investigated the mode of action of the silphinenes, plant-derived natural compounds that structurally resemble picrotoxinin. These materials antagonize the action of GABA on insect neurons and block GABA-mediated chloride uptake into mouse brain synaptoneurosomes in a noncompetitive manner. In mammals, avermectins have a blocking action on the GABA-gated chloride channel consistent with a coarse tremor, whereas at longer times and higher concentrations, activation of the channel suppresses neuronal activity. Invertebrates display ataxia, paralysis, and death as the predominant signs of poisoning, with a glutamate-gated chloride channel playing a major role. Additional target sites for the avermectins or other chloride channel-directed compounds might include receptors gated by histamine, serotonin, or acetylcholine.The voltage-sensitive chloride channels form another large gene family of chloride channels. Voltage-dependent chloride channels are involved in a number of physiological processes including: maintenance of electrical excitability, chloride ion secretion and resorption, intravesicular acidification, and cell volume regulation. A subset of these channels is affected by convulsants and insecticides in mammals, although the role they play in acute lethality in insects is unclear. Given the wide range of functions that they mediate, these channels are also potential targets for

  15. Sucrose Improves Insecticide Activity Against Drosophila suzukii (Diptera: Drosophilidae).

    Science.gov (United States)

    Cowles, Richard S; Rodriguez-Saona, Cesar; Holdcraft, Robert; Loeb, Gregory M; Elsensohn, Johanna E; Hesler, Steven P

    2015-04-01

    The addition of sucrose to insecticides targeting spotted wing drosophila, Drosophila suzukii (Matsumura), enhanced lethality in laboratory, semifield, and field tests. In the laboratory, 0.1% sucrose added to a spray solution enhanced spotted wing drosophila feeding. Flies died 120 min earlier when exposed to spinosad residues at label rates enhanced with sucrose. Added sucrose reduced the LC50 for dried acetamiprid residues from 82 to 41 ppm in the spray solution. Laboratory bioassays of spotted wing drosophila mortality followed exposure to grape and blueberry foliage and/or fruit sprayed and aged in the field. On grape foliage, the addition of 2.4 g/liter of sugar with insecticide sprays resulted in an 11 and 6% increase of spotted wing drosophila mortality at 1 and 2 d exposures to residues, respectively, averaged over seven insecticides with three concentrations. In a separate experiment, spinetoram and cyantraniliprole reduced by 95-100% the larval infestation of blueberries, relative to the untreated control, 7 d after application at labeled rates when applied with 1.2 g/liter sucrose in a spray mixture, irrespective of rainfall; without sucrose infestation was reduced by 46-91%. Adding sugar to the organically acceptable spinosyn, Entrust, reduced larval infestation of strawberries by >50% relative to without sugar for five of the six sample dates during a season-long field trial. In a small-plot field test with blueberries, weekly applications in alternating sprays of sucrose plus reduced-risk insecticides, spinetoram or acetamiprid, reduced larval infestation relative to the untreated control by 76%; alternating bifenthrin and phosmet (without sucrose) reduced infestation by 65%. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. A critical review of neonicotinoid insecticides for developmental neurotoxicity.

    Science.gov (United States)

    Sheets, Larry P; Li, Abby A; Minnema, Daniel J; Collier, Richard H; Creek, Moire R; Peffer, Richard C

    2016-02-01

    A comprehensive review of published and previously unpublished studies was performed to evaluate the neonicotinoid insecticides for evidence of developmental neurotoxicity (DNT). These insecticides have favorable safety profiles, due to their preferential affinity for nicotinic receptor (nAChR) subtypes in insects, poor penetration of the mammalian blood-brain barrier, and low application rates. Nevertheless, examination of this issue is warranted, due to their insecticidal mode of action and potential exposure with agricultural and residential uses. This review identified in vitro, in vivo, and epidemiology studies in the literature and studies performed in rats in accordance with GLP standards and EPA guidelines with imidacloprid, acetamiprid, thiacloprid, clothianidin, thiamethoxam, and dinotefuran, which are all the neonicotinoids currently registered in major markets. For the guideline-based studies, treatment was administered via the diet or gavage to primiparous female rats at three dose levels, plus a vehicle control (≥20/dose level), from gestation day 0 or 6 to lactation day 21. F1 males and females were evaluated using measures of motor activity, acoustic startle response, cognition, brain morphometry, and neuropathology. The principal effects in F1 animals were associated with decreased body weight (delayed sexual maturation, decreased brain weight, and morphometric measurements) and acute toxicity (decreased activity during exposure) at high doses, without neuropathology or impaired cognition. No common effects were identified among the neonicotinoids that were consistent with DNT or the neurodevelopmental effects associated with nicotine. Findings at high doses were associated with evidence of systemic toxicity, which indicates that these insecticides do not selectively affect the developing nervous system.

  17. Blended Refuge and Insect Resistance Management for Insecticidal Corn

    Science.gov (United States)

    Crespo, Andre L B; Pan, Zaiqi; Crain, Philip R; Thompson, Stephen D; Pilcher, Clinton D; Sethi, Amit

    2018-01-01

    Abstract In this review, we evaluate the intentional mixing or blending of insecticidal seed with refuge seed for managing resistance by insects to insecticidal corn (Zea mays). We first describe the pest biology and farming practices that will contribute to weighing trade-offs between using block refuges and blended refuges. Case studies are presented to demonstrate how the trade-offs will differ in different systems. We compare biological aspects of several abstract models to guide the reader through the history of modeling, which has played a key role in the promotion or denigration of blending in various scientific debates about insect resistance management for insecticidal crops. We conclude that the use of blended refuge should be considered on a case-by-case basis after evaluation of insect biology, environment, and farmer behavior. For Diabrotica virgifera virgifera, Ostrinia nubilalis, and Helicoverpa zea in the United States, blended refuge provides similar, if not longer, delays in the evolution of resistance compared to separate block refuges. PMID:29220481

  18. Efficacy of Selected Insecticides Applied to Hybrid Rice Seed

    Science.gov (United States)

    Adams, A.; Gore, J.; Musser, F.; Cook, D.; Walker, T.; Dobbins, C.

    2016-01-01

    Hybrid rice and insecticide seed treatments targeting rice water weevil, Lissorhoptrus oryzophilus Kuschel, have altered the landscape of rice production. The effect of reduced seeding rates on seed treatment efficacy in hybrid rice has not been studied. During 2011 and 2012, an experiment was conducted at seven locations to determine the relationship between low seeding rates used in hybrid rice and efficacy of selected insecticidal seed treatments as measured by rice water weevil densities and yield. Labeled rates of thiamethoxam, chlorantraniliprole, and clothianidin were compared with higher rates of these products to determine if labeled rates provide an acceptable level of control of the rice water weevil. Study locations were divided into low, moderate, and high groups based on rice water weevil larval densities. All seed treatments and seed treatment rates reduced rice water weevil densities. However, there was no observed yield or economic benefit from the use of an insecticidal seed treatment in areas of low pressure. Differences in yield were observed among seed treatments and seed treatment rates in moderate and high pressure locations, and all seed treatments yielded better than the untreated plots, but these differences were not always economical. All seed treatments showed an economic advantage in areas of high weevil pressure, and there were no differences among seed treatment products or rates, suggesting that currently labeled seed treatment rates in hybrid rice are effective for rice water weevil management. PMID:26537671

  19. Neonicotinoid insecticides can serve as inadvertent insect contraceptives

    Science.gov (United States)

    Villamar-Bouza, Laura; Bruckner, Selina; Chantawannakul, Panuwan; Gauthier, Laurent; Khongphinitbunjong, Kitiphong; Retschnig, Gina; Troxler, Aline; Vidondo, Beatriz; Neumann, Peter; Williams, Geoffrey R.

    2016-01-01

    There is clear evidence for sublethal effects of neonicotinoid insecticides on non-target ecosystem service-providing insects. However, their possible impact on male insect reproduction is currently unknown, despite the key role of sex. Here, we show that two neonicotinoids (4.5 ppb thiamethoxam and 1.5 ppb clothianidin) significantly reduce the reproductive capacity of male honeybees (drones), Apis mellifera. Drones were obtained from colonies exposed to the neonicotinoid insecticides or controls, and subsequently maintained in laboratory cages until they reached sexual maturity. While no significant effects were observed for male teneral (newly emerged adult) body mass and sperm quantity, the data clearly showed reduced drone lifespan, as well as reduced sperm viability (percentage living versus dead) and living sperm quantity by 39%. Our results demonstrate for the first time that neonicotinoid insecticides can negatively affect male insect reproductive capacity, and provide a possible mechanistic explanation for managed honeybee queen failure and wild insect pollinator decline. The widespread prophylactic use of neonicotinoids may have previously overlooked inadvertent contraceptive effects on non-target insects, thereby limiting conservation efforts. PMID:27466446

  20. Photodegradation of neonicotinoid insecticides in water by semiconductor oxides.

    Science.gov (United States)

    Fenoll, José; Garrido, Isabel; Hellín, Pilar; Flores, Pilar; Navarro, Simón

    2015-10-01

    The photocatalytic degradation of three neonicotinoid insecticides (NIs), thiamethoxam (TH), imidacloprid (IM) and acetamiprid (AC), in pure water has been studied using zinc oxide (ZnO) and titanium dioxide (TiO2) as photocatalysts under natural sunlight and artificial light irradiation. Photocatalytic experiments showed that the addition of these chalcogenide oxides in tandem with the electron acceptor (Na2S2O8) strongly enhances the degradation rate of these compounds in comparison with those carried out with ZnO and TiO2 alone and photolytic tests. Comparison of catalysts showed that ZnO is the most efficient for the removal of such insecticides in optimal conditions and at constant volumetric rate of photon absorption. Thus, the complete disappearance of all the studied compounds was achieved after 10 and 30 min of artificial light irradiation, in the ZnO/Na2S2O8 and TiO2/Na2S2O8 systems, respectively. The highest degradation rate was noticed for IM, while the lowest rate constant was obtained for AC under artificial light irradiation. In addition, solar irradiation was more efficient compared to artificial light for the removal of these insecticides from water. The main photocatalytic intermediates detected during the degradation of NIs were identified.

  1. Dermal insecticide residues from birds inhabiting an orchard

    Science.gov (United States)

    Vyas, N.B.; Spann, J.W.; Hulse, C.S.; Gentry, S.; Borges, S.L.

    2007-01-01

    The US Environmental Protection Agency conducts risk assessments of insecticide applications to wild birds using a model that is limited to the dietary route of exposure. However, free-flying birds are also exposed to insecticides via the inhalation and dermal routes. We measured azinphos-methyl residues on the skin plus feathers and the feet of brown-headed cowbirds (Molothrus ater) in order to quantify dermal exposure to songbirds that entered and inhabited an apple (Malus x domestica) orchard following an insecticide application. Exposure to azinphos-methyl was measured by sampling birds from an aviary that was built around an apple tree. Birds sampled at 36 h and 7-day post-application were placed in the aviary within 1 h after the application whereas birds exposed for 3 days were released into the aviary 4-day post-application. Residues on vegetation and soil were also measured. Azinphos-methyl residues were detected from the skin plus feathers and the feet from all exposure periods. Our results underscore the importance of incorporating dermal exposure into avian pesticide risk assessments.

  2. Evolution of resistance to pyrethroid insecticides in Musca domestica.

    Science.gov (United States)

    Scott, Jeffrey G

    2017-04-01

    Houseflies, Musca domestica L., are a significant pest because of the numerous diseases they transmit. Control of housefly populations, particularly at animal production facilities, is frequently done using pyrethroid insecticides which kill insects by prolonging the open time of the voltage-sensitive sodium channel (VSSC). Houseflies have evolved resistance to pyrethroids owing to mutations in Vssc and by cytochrome-P450-mediated detoxification. Three Vssc mutations are known: kdr (L1014F), kdr-his (L1014H) and super-kdr (M918T + L1014F). Generally, the levels of resistance conferred by these mutations are kdr-his resistance than kdr. P450-mediated resistance can result from overexpression of CYP6D1 or another P450 (unidentified) whose overexpression is linked to autosomes II or V. The initial use of field-stable pyrethroids resulted in different patterns of evolution across the globe, but with time these mutations have become more widespread in their distribution. What is known about the fitness costs of the resistance alleles in the absence of insecticide is discussed, particularly with respect to the current and future utility of pyrethroid insecticides. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  3. Mdr65 decreases toxicity of multiple insecticides in Drosophila melanogaster.

    Science.gov (United States)

    Sun, Haina; Buchon, Nicolas; Scott, Jeffrey G

    2017-10-01

    ABC transporters are ubiquitous membrane-bound proteins, present in both prokaryotes and eukaryotes. The major function of eukaryotic ABC transporters is to mediate the efflux of a variety of substrates (including xenobiotics) out of cells. ABC transporters have been widely investigated in humans, particularly for their involvement in multidrug resistance (MDR). Considerably less is known about their roles in transport and/or excretion in insects. ABC transporters are only known to function as exporters in insects. Drosophila melanogaster has 56 ABC transporter genes, including eight which are phylogenetically most similar to the human Mdr genes (ABCB1 clade). We investigated the role of ABC transporters in the ABCB1 clade in modulating the susceptibility to insecticides. We took advantage of the GAL4/UAS system in D. melanogaster to knockdown the expression levels of Mdr65, Mdr50, Mdr49 and ABCB6 using transgenic UAS-RNAi lines and conditional driver lines. The most notable effects were increased sensitivities to nine different insecticides by silencing of Mdr65. Furthermore, a null mutation of Mdr65 decreased the malathion, malaoxon and fipronil LC 50 values by a factor of 1.9, 2.1 and 3.9, respectively. Altogether, this data demonstrates the critical role of ABC transporters, particularly Mdr65, in altering the toxicity of specific, structurally diverse, insecticides in D. melanogaster. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Substances inertes et plantes à effet insecticide utilisées dans la ...

    African Journals Online (AJOL)

    Les insecticides naturels tels que les plantes à effet insecticide et les substances inertes (sable, cendre, terres à diatomées,…) méritent d'être valorisées afin de réduire l'utilisation des insecticides chimiques et protéger l'environnement. Ce travail basé sur une revue documentaire fouillée et actualisée vise à faire la genèse ...

  5. Determination of insecticides malathion and lambda-cyhalothrin residues in zucchini by gas chromatography

    OpenAIRE

    Lofty, Hayam M.; Abd El-Aleem, Abd El-Aziz A.; Monir, Hany H.

    2013-01-01

    A sensitive gas chromatographic method has been developed for the determination of malathion and lambda-cyhalothrin (λ-cyhalothrin) insecticide residues in zucchini. The developed method consists of extraction with acetone, purification and partitioning with methylene chloride, column chromatographic clean-up, and finally capillary gas chromatographic determination of the insecticides. The recoveries of method were greater than 90% and limit of determination was 0.001 ppm for both insecticide...

  6. Insecticide susceptibility of Anopheles mosquitoes changes in response to variations in the larval environment.

    Science.gov (United States)

    Owusu, Henry F; Chitnis, Nakul; Müller, Pie

    2017-06-16

    Insecticide resistance threatens the success achieved through vector control in reducing the burden of malaria. An understanding of insecticide resistance mechanisms would help to develop novel tools and strategies to restore the efficacy of insecticides. Although we have substantially improved our understanding of the genetic basis of insecticide resistance over the last decade, we still know little of how environmental variations influence the mosquito phenotype. Here, we measured how variations in larval rearing conditions change the insecticide susceptibility phenotype of adult Anopheles mosquitoes. Anopheles gambiae and A. stephensi larvae were bred under different combinations of temperature, population density and nutrition, and the emerging adults were exposed to permethrin. Mosquitoes bred under different conditions showed considerable changes in mortality rates and body weight, with nutrition being the major factor. Weight is a strong predictor of insecticide susceptibility and bigger mosquitoes are more likely to survive insecticide treatment. The changes can be substantial, such that the same mosquito colony may be considered fully susceptible or highly resistant when judged by World Health Organization discriminatory concentrations. The results shown here emphasise the importance of the environmental background in developing insecticide resistance phenotypes, and caution for the interpretation of data generated by insecticide susceptibility assays.

  7. Current Perspectives on Plague Vector Control in Madagascar: Susceptibility Status of Xenopsylla cheopis to 12 Insecticides.

    Science.gov (United States)

    Miarinjara, Adélaïde; Boyer, Sébastien

    2016-02-01

    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.

  8. Ecotoxicity of binary mixtures of Microcystis aeruginosa and insecticides to Daphnia pulex

    International Nuclear Information System (INIS)

    Asselman, J.; Janssen, C.R.; Smagghe, G.; De Schamphelaere, K.A.C.

    2014-01-01

    In aquatic ecosystems, mixtures of chemical and natural stressors can occur which may significantly complicate risk assessment approaches. Here, we show that effects of binary combinations of four different insecticides and Microcystis aeruginosa, a toxic cyanobacteria, on Daphnia pulex exhibited distinct interaction patterns. Combinations with chlorpyrifos and tetradifon caused non-interactive effects, tebufenpyrad caused an antagonistic interaction and fenoyxcarb yielded patterns that depended on the reference model used (i.e. synergistic with independent action, additive with concentration addition). Our results demonstrate that interactive effects cannot be generalised across different insecticides, not even for those targeting the same biological pathway (i.e. tebufenpyrad and tetradifon both target oxidative phosphorylation). Also, the concentration addition reference model provided conservative predictions of effects in all investigated combinations for risk assessment. These predictions could, in absence of a full mechanistic understanding, provide a meaningful solution for managing water quality in systems impacted by both insecticides and cyanobacterial blooms. - Highlights:: • 2 of 4 insecticide-Microcystis combinations showed no interactive effect on Daphnia. • One insecticide showed antagonistic deviation patterns. • For one other insecticide the results depended on the reference model used. • Interactive effects between insecticides and Microcystis cannot be generalized. • The concentration addition model provides conservative estimates of mixture effects. - Interactive effects between insecticides and cyanobacterial stressors cannot be generalized, not even for insecticides with closely related known modes of action

  9. Effects of irrigation levels on interactions among Lygus hesperus (Hemiptera: Miridae), insecticides, and predators in cotton.

    Science.gov (United States)

    Asiimwe, Peter; Naranjo, Steven E; Ellsworth, Peter C

    2014-04-01

    Variation in plant quality and natural enemy abundance plays an important role in insect population dynamics. In manipulative field studies, we evaluated the impact of varying irrigation levels and insecticide type on densities of Lygus hesperus Knight and the arthropod predator community in cotton. Three watering levels were established via irrigations timed according to three levels of percent soil water depletion (SWD): 20, 40, or 60, where 40% SWD is considered standard grower practice, 60% represents a deficit condition likely to impose plant productivity losses, and 20% represents surplus conditions with likely consequences on excessive vegetative plant production. The two key L. hesperus insecticides used were the broad-spectrum insecticide acephate and the selective insecticide flonicamid, along with an untreated check. We hypothesized that densities of L. hesperus and its associated predators would be elevated at higher irrigation levels and that insecticides would differentially impact L. hesperus and predator dynamics depending on their selectivity. L. hesperus were more abundant at the higher irrigation level (20% SWD) but the predator densities were unaffected by irrigation levels. Both L. hesperus and its predators were affected by the selectivity of the insecticide with highest L. hesperus densities and lowest predator abundance where the broad spectrum insecticide (acephate) was used. There were no direct interactions between irrigation level and insecticides, indicating that insecticide effects on L. hesperus and its predators were not influenced by the irrigation levels used here. The implications of these findings on the overall ecology of insect-plant dynamics and yield in cotton are discussed.

  10. Degradation of Organophosphorus and Pyrethroid Insecticides in Beverages: Implications for Risk Assessment

    Directory of Open Access Journals (Sweden)

    Samantha A. Radford

    2018-02-01

    Full Text Available Since urinary insecticide metabolites are commonly used as biomarkers of exposure, it is important that we quantify whether insecticides degrade in food and beverages in order to better perform risk assessment. This study was designed to quantify degradation of organophosphorus and pyrethroid insecticides in beverages. Purified water, white grape juice, orange juice, and red wine were fortified with 500 ng/mL diazinon, malathion, chlorpyrifos, permethrin, cyfluthrin, cypermethrin, and deltamethrin, and aliquots were extracted several times over a 15-day storage period at 2.5 °C. Overall, statistically significant loss of at least one insecticide was observed in each matrix, and at least five out of seven insecticides demonstrated a statistically significant loss in all matrices except orange juice. An investigation of an alternative mechanism of insecticide loss—adsorption onto the glass surface of the storage jars—was carried out, which indicated that this mechanism of loss is insignificant. Results of this work suggest that insecticides degrade in these beverages, and this degradation may lead to pre-existing insecticide degradates in the beverages, suggesting that caution should be exercised when using urinary insecticide metabolites to assess exposure and risk.

  11. Evaluation of the Insecticidal Efficacy of Wild Type and Recombinant Baculoviruses.

    Science.gov (United States)

    Popham, Holly J R; Ellersieck, Mark R; Li, Huarong; Bonning, Bryony C

    2016-01-01

    A considerable amount of work has been undertaken to genetically enhance the efficacy of baculovirus insecticides. Following construction of a genetically altered baculovirus, laboratory bioassays are used to quantify various parameters of insecticidal activity such as the median lethal concentration (or dose) required to kill 50 % of infected larvae (LC50 or LD50), median survival of larvae infected (ST50), and feeding damage incurred by infected larvae. In this chapter, protocols are described for a variety of bioassays and the corresponding data analyses for assessment of the insecticidal activity of baculovirus insecticides.

  12. Protective effect and economic impact of insecticide application methods on barley

    Directory of Open Access Journals (Sweden)

    Alfred Stoetzer

    2014-03-01

    Full Text Available The objective of this work was to evaluate the protective effect of different forms of insecticide application on the transmission of yellow dwarf disease in barley cultivars, as well as to determine the production costs and the net profit of these managements. The experiments were carried out during 2011 and 2012 growing seasons, using the following managements at main plots: T1, seed treatment with insecticide (ST + insecticide on shoots at 15-day interval; T2, just ST; T3, insecticide applied on shoots, when aphid control level (CL was reached; T4, without insecticide; and T5, ST + insecticide on shoots when CL was reached. Different barley cultivars - BRS Cauê, BRS Brau and MN 6021 - were arranged in the subplots. Insecticides lambda cyhalothrin (pyrethroid and thiamethoxam (neonicotinoid were used. There were differences on yellow dwarf disease index in both seasons for the different treatments, while damage to grain yield was influenced by year and aphid population. Production costs and net profit were different among treatments. Seed treatment with insecticide is sufficient to reduce the transmission of yellow dwarf disease in years with low aphid population pressure, while in years with larger populations, the application of insecticide on shoots is also required.

  13. Does multigenerational exposure to hormetic concentrations of imidacloprid precondition aphids for increased insecticide tolerance?

    Science.gov (United States)

    Rix, Rachel R; Cutler, G Christopher

    2018-02-01

    Hormetic preconditioning, whereby exposure to mild stress primes an organism to better tolerate subsequent stress, is well documented. It is unknown if exposure to hormetic concentrations of insecticide can trans-generationally prime insects to better tolerate insecticide exposure, or whether exposure to hormetic concentrations of insecticide can induce mutations in genes responsible for insecticide resistance. Using the aphid Myzus persicae (Sulzer) and the insecticide imidacloprid as a model, we examined if exposure to mildly toxic and hormetic concentrations of imidacloprid reduced aphid susceptibility to insecticides across four generations, and whether such exposures induced mutations in the imidacloprid binding site in post-synaptic nicotinic acetylcholine receptors. Chronic, multigenerational exposure of aphids to hormetic concentrations of imidacloprid primed offspring to better survive exposure to certain concentrations of imidacloprid, but not exposure to spirotetramat, an insecticide with a different mode of action. Exposure to hormetic and mildly toxic concentrations of imidacloprid did not result in mutations in any of the examined nicotinic acetylcholine receptor subunits. Our findings demonstrate that exposure to hormetic concentrations of insecticide can prime insects to better withstand subsequent chemical stress, but this is dependent upon the insecticide exposure scenario, and may be subtle over generations. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  14. Effects of persistent insecticides on beneficial soil arthropod in conventional fields compared to organic fields, puducherry.

    Science.gov (United States)

    Anbarashan, Padmavathy; Gopalswamy, Poyyamoli

    2013-07-15

    The usage of synthetic fertilizers/insecticides in conventional farming has dramatically increased over the past decades. The aim of the study was to compare the effects of bio-pesticides and insecticides/pesticides on selected beneficial non targeted arthropods. Orders Collembola, Arachinida/Opiliones, Oribatida and Coleoptera were the main groups of arthropods found in the organic fields and Coleoptera, Oribatida, Gamasida and Collembola in conventional fields. Pesticides/insecticides had a significant effect on non-targeted arthropods order- Collembola, Arachinida/Opiliones, Hymenoptera and Thysonoptera were suppressed after pesticides/insecticides spraying. Bio-insecticides in organic fields had a non-significant effect on non targeted species and they started to increase in abundance after 7 days of spraying, whereas insecticide treatment in conventional fields had a significant long-term effect on non targeted arthropods and short term effect on pests/insects, it started to increase after 21 days of the spraying. These results indicate that insecticide treatment kept non targeted arthropods at low abundance. In conclusion, organic farming does not significantly affected the beneficial-non targeted arthropods biodiversity, whereas preventive insecticide application in conventional fields had significant negative effects on beneficial non targeted arthropods. Therefore, conventional farmers should restrict insecticide applications, unless pest densities reach the thresholds and more desirably can switch to organic farming practices.

  15. Impact and Selectivity of Insecticides to Predators and Parasitoids

    Directory of Open Access Journals (Sweden)

    Flávio Lemes Fernandes

    2010-04-01

    Full Text Available Problems with the use of insecticides has brought losses, such as, negative impact on natural enemies. When these beneficial insects reduce cause the eruption of pests and resurgence it’s more common. Thus principles of conservation these arthropods are extremely important in the biological natural control of pests, so that these enemies may present a high performance. Because of the negative impacts caused by insecticides on agriculture and their harmful effects on natural enemies, the objective of this article is to approach two important subjects, divided into three parts. Part I relates to the description of the main crop pests and their natural enemies; Part II involves the impact of insecticides on predators and parasitoids and Part III focuses on the selectivity of several groups of insecticides to natural enemies. Before spraying insecticides, it is necessary to choose a product that is efficient to pests and selective to natural enemies. So, it is indispensable to identify correctly the groups and species of natural enemies, since insecticides have an impact on their survival, growth, development, reproduction (sexual ratio, fecundity, longevity and fertility, and behavior (motility, orientation, feeding, oviposition and learning of insects. The mechanisms of toxicity and selectivity of insecticides are related to the properties of higher or lower solubility and molecular weight. Besides, characteristics of the cuticular composition of the integument of natural enemies are extremely important in the selectivity of a product or the tolerance of a certain predator or parasitoid to this molecules.Impacto e Seletividade de Inseticidas para Predadores e ParasitóidesResumo.Dentre os problemas advindos do uso de inseticidas, a destruição de inimigos naturais é fator importante. Estes insetos benéficos podem reduzir problemas de erupção de pragas secundárias, ressurgência de pragas e manter a praga abaixo do nível de dano econ

  16. Sequence-selective single-molecule alkylation with a pyrrole-imidazole polyamide visualized in a DNA nanoscaffold.

    Science.gov (United States)

    Yoshidome, Tomofumi; Endo, Masayuki; Kashiwazaki, Gengo; Hidaka, Kumi; Bando, Toshikazu; Sugiyama, Hiroshi

    2012-03-14

    We demonstrate a novel strategy for visualizing sequence-selective alkylation of target double-stranded DNA (dsDNA) using a synthetic pyrrole-imidazole (PI) polyamide in a designed DNA origami scaffold. Doubly functionalized PI polyamide was designed by introduction of an alkylating agent 1-(chloromethyl)-5-hydroxy-1,2-dihydro-3H-benz[e]indole (seco-CBI) and biotin for sequence-selective alkylation at the target sequence and subsequent streptavidin labeling, respectively. Selective alkylation of the target site in the substrate DNA was observed by analysis using sequencing gel electrophoresis. For the single-molecule observation of the alkylation by functionalized PI polyamide using atomic force microscopy (AFM), the target position in the dsDNA (∼200 base pairs) was alkylated and then visualized by labeling with streptavidin. Newly designed DNA origami scaffold named "five-well DNA frame" carrying five different dsDNA sequences in its cavities was used for the detailed analysis of the sequence-selectivity and alkylation. The 64-mer dsDNAs were introduced to five individual wells, in which target sequence AGTXCCA/TGGYACT (XY = AT, TA, GC, CG) was employed as fully matched (X = G) and one-base mismatched (X = A, T, C) sequences. The fully matched sequence was alkylated with 88% selectivity over other mismatched sequences. In addition, the PI polyamide failed to attach to the target sequence lacking the alkylation site after washing and streptavidin treatment. Therefore, the PI polyamide discriminated the one mismatched nucleotide at the single-molecule level, and alkylation anchored the PI polyamide to the target dsDNA.

  17. A Role for 2-Methyl Pyrrole in the Browning of 4-Oxopentanal and Limonene Secondary Organic Aerosol

    Energy Technology Data Exchange (ETDEWEB)

    Aiona, Paige K. [Department; Lee, Hyun Ji [Department; Lin, Peng [Department; Heller, Forrest [Environmental; Laskin, Alexander [Department; Laskin, Julia [Department; Nizkorodov, Sergey A. [Department

    2017-09-15

    “Brown Carbon” (BrC) is a type of organic particulate matter that absorbs visible and near ultraviolet radiation. Reactions of carbonyls in secondary organic aerosol (SOA) produced from limonene with ammonia (NH3) or ammonium sulfate (AS) are known to produce BrC with a distinctive absorption band at 500 nm. Although the general mechanism for this process has been proposed in previous studies, the specific molecular structures of the light-absorbing species remain unclear. This study examined the browning processes occurring in aqueous solutions of AS and 4-oxopentanal (4-OPA), which has a 1,4-dicarbonyl structural motif present in many limonene SOA compounds. The reaction of 4-OPA with AS in a bulk aqueous solution produces a 2-methyl pyrrole (2-MP) intermediate, which is not a strong light absorber by itself, but can react further with carbonyl compounds leading to the eventual formation of BrC chromophores. The direct involvement of 2-MP in the browning process was demonstrated by reacting 2-MP with 4-OPA and with limonene SOA, both of which produced BrC chromophores with distinctive absorption bands at visible wavelengths. The formation of BrC in reaction of 4-OPA with AS and ammonium nitrate (AN) was found to be accelerated by evaporation of the solution suggesting an important role of the dehydration processes in BrC formation from 1,4- dicarbonyls. 4-OPA was also found to produce BrC in aqueous reactions with a broad spectrum of amino acids and amines. The results suggest that 4-OPA may be the smallest atmospherically relevant compound capable of browning by the same mechanism as limonene SOA.

  18. Effects of altered platelet number on pulmonary hypertension and platelet sequestration in monocrotaline pyrrole-treated rats

    International Nuclear Information System (INIS)

    White, S.M.; Wagner, J.G.; Roth, R.A.

    1989-01-01

    To study the role of platelets in monocrotaline pyrrole (MCTP)-induced pulmonary hypertension, pulmonary sequestration of 111In-labeled platelets in rats treated with MCTP and anti-rat platelet serum (PAS) was examined. Lung injury from a single, intravenous injection of MCTP (3.5 mg/kg) at Day 8 was evident as elevated lung weight and lavage fluid protein and lactate dehydrogenase activity. Additionally, right ventricular hypertrophy and elevated pulmonary arterial pressures (PAP) occurred. Treatment with PAS on Days 6-8 did not affect the lung injury but resulted in an attenuation of the pulmonary hypertensive response. Pulmonary platelet sequestration was also decreased in PAS-treated rats, yet the sequestration in the lungs of MCTP-treated rats that received PAS was significantly higher than that in the lungs of N,N-dimethylformamide (DMF) controls. MCTP-treated rats receiving control serum (CS) tended to sequester more 111In-labeled platelets than respective DMF controls, but this was not statistically significant. Blood platelet half-life was unaltered in rats receiving CS. When rats were treated similarly with MCTP and PAS and were killed at 18 days, the attenuation of the pulmonary hypertensive response previously described was not observed, and lung injury was more extensive than when CS was given. Apparently, platelet depletion delayed the development of the pulmonary hypertensive response. Supranormal platelet numbers produced by splenectomy did not affect MCTP-induced lung injury or the elevation in PAP. These results support the hypothesis that the development of MCTP-induced pulmonary hypertension is mediated in part by platelets

  19. PTCA (1H-pyrrole-2,3,5-tricarboxylic acid) as a marker for oxidative hair treatment.

    Science.gov (United States)

    Petzel-Witt, Silvana; Meier, Sylvia I; Schubert-Zsilavecz, Manfred; Toennes, Stefan W

    2018-04-01

    Hair analysis for the assessment of alcohol or drug abstinence has become a routine procedure in forensic toxicology. Hair coloration leading to loss of incorporated xenobiotics and to false negative results has turned out to be a major problem. Currently only colored extracts provide hints of manipulations but not bleaching. A liquid chromatographic-tandem mass spectrometric (LC-MS/MS) method was developed and validated to determine 1H-pyrrole-2,3,5-tricarboxylic acid (PTCA), a major oxidation product of melanin. PTCA was determined in natural hair samples (n = 21) after treatment with 3% hydrogen peroxide (H 2 O 2 ) for 30 or 40 minutes with concentrations up to 12% for 40 minutes. In another series, 12 natural hair samples were submitted to different coloration procedures (henna, tinting, semi-permanent and permanent dyeing, bleaching) and the changes in PTCA content were determined. A significant increase in the PTCA content was found for both incubation times and increasing H 2 O 2 concentrations. Coloration with henna or tinting had no influence on PTCA levels detected, but a significant increase was observed after semi-permanent and permanent dyeing and bleaching. As PTCA concentrations in natural hair were found to be in a range of <2.1-16.4 ng/mg (8.4 ± 3.8 ng/mg, mean ± SD, n = 33), a cut-off of 20 ng/mg is recommended for the distinction between natural vs. excessively oxidized hair. In case of naturally low melanin content (light-blond or white hair), no marked increase in PTCA may occur. The present study demonstrated that PTCA is formed during oxidative treatment of melanin in hair, which can be used to detect previous hair coloration including oxidation. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Poly (pyrrole-co-aniline) hollow nanosphere supported Pd nanoflowers as high-performance catalyst for methanol electrooxidation in alkaline media

    International Nuclear Information System (INIS)

    Fard, Leyla Abolghasemi; Ojani, Reza; Raoof, Jahan Bakhsh; Zare, Ehsan Nazarzadeh; Lakouraj, Moslem Mansour

    2017-01-01

    In this work, first poly (pyrrole-co-aniline) (PPCA) hollow nanosphere (HN) as a catalyst support material is fabricated through in-situ emulsion polymerization. Then we reported a one-step and template-free approach to fabricate Pd NFs on a PPCA HN coated glassy carbon electrode by a facile electrochemical approach. Several techniques such as FTIR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy) and EDS (energy dispersive spectroscopy) were utilized for the characterization of the synthesized materials. The catalytic performance of Pd NFs/PPCA HN catalyst is evaluated by cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy toward methanol oxidation as a model reaction in alkaline media. The comparison of specific activities for Pd NFs/PPCA HN (1.79 mA cm"−"2), Pd NFs/PPy (1.28 mA cm"−"2), Pd NFs/PANI (0.93 mA cm"−"2) and Pd NFs (0.78 mA cm"−"2) shows that the PPCA supported Pd NFs with high surface area exhibits the excellent electrocatalytic activity than other electrodes for the electro-oxidation reaction in alkaline media. This might be due to the easier charge transfer at conductive copolymer interfaces, higher electrochemically accessible surface areas and electronic conductivity. This strategy provides a promising platform for direct methanol fuel cells. - Highlights: • Pd nanoflowers supported on poly (pyrrole-co-aniline) hollow nanosphere is prepared by a facile electrochemical approach. • The as-prepared nanocatalyst displays the enhanced electrocatalytic activity and stability for methanol oxidation. • The high performance is attributed to facile electron transfer on poly (pyrrole-co-aniline) hollow nanosphere substrate.

  1. Sensitivity of Bemisia Tabaci (Hemiptera: Aleyrodidae) to Several New Insecticides in China: Effects of Insecticide Type and Whitefly Species, Strain, and Stage

    Science.gov (United States)

    Xie, Wen; Liu, Yang; Wang, Shaoli; Wu, Qingjun; Pan, Huipeng; Yang, Xin; Guo, Litao; Zhang, Youjun

    2014-01-01

    Abstract Whitefly biotypes B and Q are the two most damaging members of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex. Control of B. tabaci (and especially of Q) has been impaired by resistance to commonly used insecticides. To find new insecticides for B. tabaci management in China, we investigated the sensitivity of eggs, larvae, and adults of laboratory strains of B and Q (named Lab-B and Lab-Q) and field strains of Q to several insecticides. For eggs, larvae, and adults of B. tabaci and for six insecticides (cyantraniliprole, chlorantraniliprole, pyriproxyfen, buprofezin, acetamiprid, and thiamethoxam), LC 50 values were higher for Lab-Q than for Lab-B; avermectin LC 50 values, however, were low for adults of both Lab-Q and Lab-B. Based on the laboratory results, insecticides were selected to test against eggs, larvae, and adults of four field strains of B. tabaci Q. Although the field strains differed in their sensitivity to the insecticides, the eggs and larvae of all strains were highly sensitive to cyantraniliprole, and the adults of all strains were highly sensitive to avermectin. The eggs, larvae, and adults of B. tabaci Q were generally more resistant than those of B. tabaci B to the tested insecticides. B. tabaci Q eggs and larvae were sensitive to cyantraniliprole and pyriproxyfen, whereas B. tabaci Q adults were sensitive to avermectin. Field trials should be conducted with cyantraniliprole, pyriproxyfen, and avermectin for control of B. tabaci Q and B in China. PMID:25434040

  2. Insecticide Resistance and Metabolic Mechanisms Involved in Larval and Adult Stages of Aedes aegypti Insecticide-Resistant Reference Strains from Cuba.

    Science.gov (United States)

    Bisset, Juan Andrés; Rodríguez, María Magdalena; French, Leydis; Severson, David W; Gutiérrez, Gladys; Hurtado, Daymi; Fuentes, Ilario

    2014-12-01

    Studies were conducted to compare levels of insecticide resistance and to determine the metabolic resistance mechanisms in larval and adult stages of Aedes aegypti from Cuba. Three insecticide-resistant reference strains of Ae. aegypti from Cuba were examined. These strains were derived from a Santiago de Cuba strain isolated in 1997; it was previously subjected to a strong selection for resistance to temephos (SAN-F6), deltamethrin (SAN-F12), and propoxur (SAN-F13) and routinely maintained in the laboratory under selection pressure up to the present time, when the study was carried out. In addition, an insecticide-susceptible strain was used for comparison. The insecticide resistance in larvae and adults was determined using standard World Health Organization methodologies. Insecticide resistance mechanisms were determined by biochemical assays. The esterases (α EST and β EST) and mixed function oxidase (MFO) activities were significantly higher in adults than in the larvae of the three resistant strains studied. The association of resistance level with the biochemical mechanism for each insecticide was established for each stage. The observed differences between larval and adult stages of Ae. aegypti in their levels of insecticide resistance and the biochemical mechanisms involved should be included as part of monitoring and surveillance activities in Ae. aegypti vector control programs.

  3. Degradation of Insecticides in Poultry Manure: Determining the Insecticidal Treatment Interval for Managing House Fly (Diptera: Muscidae) Populations in Poultry Farms.

    Science.gov (United States)

    Ong, Song-Quan; Ab Majid, Abdul Hafiz; Ahmad, Hamdan

    2016-04-01

    It is crucial to understand the degradation pattern of insecticides when designing a sustainable control program for the house fly, Musca domestica (L.), on poultry farms. The aim of this study was to determine the half-life and degradation rates of cyromazine, chlorpyrifos, and cypermethrin by spiking these insecticides into poultry manure, and then quantitatively analyzing the insecticide residue using ultra-performance liquid chromatography. The insecticides were later tested in the field in order to study the appropriate insecticidal treatment intervals. Bio-assays on manure samples were later tested at 3, 7, 10, and 15 d for bio-efficacy on susceptible house fly larvae. Degradation analysis demonstrated that cyromazine has the shortest half-life (3.01 d) compared with chlorpyrifos (4.36 d) and cypermethrin (3.75 d). Cyromazine also had a significantly greater degradation rate compared with chlorpyrifos and cypermethrin. For the field insecticidal treatment interval study, 10 d was the interval that had been determined for cyromazine due to its significantly lower residue; for ChCy (a mixture of chlorpyrifos and cypermethrin), the suggested interval was 7 d. Future work should focus on the effects of insecticide metabolites on targeted pests and the poultry manure environment.

  4. Diethyl 2,2′-({[1,4-phenylenebis(azanediyl]bis(methylene}bis(1H-pyrrole-2,1-diyldiacetate

    Directory of Open Access Journals (Sweden)

    Jasim Alshawi

    2016-01-01

    Full Text Available The complete molecule of the title compound, C24H30N4O4, is generated by crystallographic inversion symmetry. The molecule is S-shaped and the pyrrole groups have an anti or trans confirmation with respect to the central benzene ring, to which they are inclined by 76.38 (9°. In the crystal, molecules are linked via C—H...O hydrogen bonds, forming layers parallel to the ac plane. Within the layers there are C—H...π interactions present. There are, however, no significant interactions between the layers.

  5. Structure and spectroscopic properties of N,S-coordinating 2-methyl-sulfanyl-N-[(1H-pyrrol-2-yl)methyl-idene]aniline methanol monosolvate.

    Science.gov (United States)

    Richards, D Douglas; Ang, M Trisha C; McDonald, Robert; Bierenstiel, Matthias

    2015-10-01

    The reaction of pyrrole-2-carboxaldehyde and 2-(methyl-sulfan-yl)aniline in refluxing methanol gave an olive-green residue in which yellow crystals of the title compound, C12H12N2S·CH3OH, were grown from slow evaporation of methanol at 263 K. In the crystal, hydrogen-bonding inter-actions link the aniline mol-ecule and a nearby methanol solvent mol-ecule. These units are linked by a pair of weak C-H⋯Omethanol interactions, forming inversion dimers consisting of two main molecules and two solvent molecules.

  6. Rhodium/Silver-Cocatalyzed Transannulation of N-Sulfonyl-1,2,3-triazoles with Vinyl Azides: Divergent Synthesis of Pyrroles and 2 H-Pyrazines.

    Science.gov (United States)

    Zhang, Lin; Sun, Ge; Bi, Xihe

    2016-11-07

    The first cyclization reaction between vinyl azides and N-sulfonyl-1,2,3-triazoles is reported. A Rh/Ag binary metal catalyst system proved to be necessary for the successful cyclization. By varying the structure of vinyl azides, such reaction allows the divergent synthesis of pyrroles and 2H-pyrazines. The cyclization reactions feature a broad substrate scope, good functional group tolerance, high reaction efficiency, and good to high product yields. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Structure and spectroscopic properties of N,S-coordinating 2-methylsulfanyl-N-[(1H-pyrrol-2-ylmethylidene]aniline methanol monosolvate

    Directory of Open Access Journals (Sweden)

    D. Douglas Richards

    2015-10-01

    Full Text Available The reaction of pyrrole-2-carboxaldehyde and 2-(methylsulfanylaniline in refluxing methanol gave an olive-green residue in which yellow crystals of the title compound, C12H12N2S·CH3OH, were grown from slow evaporation of methanol at 263 K. In the crystal, hydrogen-bonding interactions link the aniline molecule and a nearby methanol solvent molecule. These units are linked by a pair of weak C—H...Omethanol interactions, forming inversion dimers consisting of two main molecules and two solvent molecules.

  8. Gut Microbiota Mediate Insecticide Resistance in the Diamondback Moth, Plutella xylostella (L.).

    Science.gov (United States)

    Xia, Xiaofeng; Sun, Botong; Gurr, Geoff M; Vasseur, Liette; Xue, Minqian; You, Minsheng

    2018-01-01

    The development of insecticide resistance in insect pests is a worldwide concern and elucidating the underlying mechanisms is critical for effective crop protection. Recent studies have indicated potential links between insect gut microbiota and insecticide resistance and these may apply to the diamondback moth, Plutella xylostella (L.), a globally and economically important pest of cruciferous crops. We isolated Enterococcus sp. (Firmicutes), Enterobacter sp. (Proteobacteria), and Serratia sp. (Proteobacteria) from the guts of P. xylostella and analyzed the effects on, and underlying mechanisms of insecticide resistance. Enterococcus sp. enhanced resistance to the widely used insecticide, chlorpyrifos, in P. xylostella , while in contrast, Serratia sp. decreased resistance and Enterobacter sp. and all strains of heat-killed bacteria had no effect. Importantly, the direct degradation of chlorpyrifos in vitro was consistent among the three strains of bacteria. We found that Enterococcus sp., vitamin C, and acetylsalicylic acid enhanced insecticide resistance in P. xylostella and had similar effects on expression of P. xylostella antimicrobial peptides. Expression of cecropin was down-regulated by the two compounds, while gloverin was up-regulated. Bacteria that were not associated with insecticide resistance induced contrasting gene expression profiles to Enterococcus sp. and the compounds. Our studies confirmed that gut bacteria play an important role in P. xylostella insecticide resistance, but the main mechanism is not direct detoxification of insecticides by gut bacteria. We also suggest that the influence of gut bacteria on insecticide resistance may depend on effects on the immune system. Our work advances understanding of the evolution of insecticide resistance in this key pest and highlights directions for research into insecticide resistance in other insect pest species.

  9. Gut Microbiota Mediate Insecticide Resistance in the Diamondback Moth, Plutella xylostella (L.

    Directory of Open Access Journals (Sweden)

    Xiaofeng Xia

    2018-01-01

    Full Text Available The development of insecticide resistance in insect pests is a worldwide concern and elucidating the underlying mechanisms is critical for effective crop protection. Recent studies have indicated potential links between insect gut microbiota and insecticide resistance and these may apply to the diamondback moth, Plutella xylostella (L., a globally and economically important pest of cruciferous crops. We isolated Enterococcus sp. (Firmicutes, Enterobacter sp. (Proteobacteria, and Serratia sp. (Proteobacteria from the guts of P. xylostella and analyzed the effects on, and underlying mechanisms of insecticide resistance. Enterococcus sp. enhanced resistance to the widely used insecticide, chlorpyrifos, in P. xylostella, while in contrast, Serratia sp. decreased resistance and Enterobacter sp. and all strains of heat-killed bacteria had no effect. Importantly, the direct degradation of chlorpyrifos in vitro was consistent among the three strains of bacteria. We found that Enterococcus sp., vitamin C, and acetylsalicylic acid enhanced insecticide resistance in P. xylostella and had similar effects on expression of P. xylostella antimicrobial peptides. Expression of cecropin was down-regulated by the two compounds, while gloverin was up-regulated. Bacteria that were not associated with insecticide resistance induced contrasting gene expression profiles to Enterococcus sp. and the compounds. Our studies confirmed that gut bacteria play an important role in P. xylostella insecticide resistance, but the main mechanism is not direct detoxification of insecticides by gut bacteria. We also suggest that the influence of gut bacteria on insecticide resistance may depend on effects on the immune system. Our work advances understanding of the evolution of insecticide resistance in this key pest and highlights directions for research into insecticide resistance in other insect pest species.

  10. Impact of reduced-risk insecticides on soybean aphid and associated natural enemies.

    Science.gov (United States)

    Ohnesorg, Wayne J; Johnson, Kevin D; O'Neal, Matthew E

    2009-10-01

    Insect predators in North America suppress Aphis glycines Matsumura (Hemiptera: Aphididae) populations; however, insecticides are required when populations reach economically damaging levels. Currently, insecticides used to manage A. glycines are broad-spectrum (pyrethroids and organophosphates), and probably reduce beneficial insect abundance in soybean, Glycine max (L.) Merr. Our goal was to determine whether insecticides considered reduced-risk by the Environmental Protection Agency could protect soybean yield from A. glycines herbivory while having a limited impact on the aphid's natural enemies. We compared three insecticides (imidacloprid, thiamethoxam, and pymetrozine,) to a broad-spectrum insecticide (lamda-cyhalothrin) and an untreated control using two application methods. We applied neonicotinoid insecticides to seeds (imidacloprid and thiamethoxam) as well as foliage (imidacloprid); pymetrozine and lamda-cyhalothrin were applied only to foliage. Foliage-applied insecticides had lower A. glycines populations and higher yields than the seed-applied insecticides. Among foliage-applied insecticides, pymetrozine and imidacloprid had an intermediate level of A. glycines population and yield protection compared with lamda-cyhalothrin and the untreated control. We monitored natural enemies with yellow sticky cards, sweep-nets, and direct observation. Before foliar insecticides were applied (i.e., before aphid populations developed) seed treatments had no observable effect on the abundance of natural enemies. After foliar insecticides were applied, differences in natural enemy abundance were observed when sampled with sweep-nets and direct observation but not with yellow sticky cards. Based on the first two sampling methods, pymetrozine and the foliage-applied imidacloprid had intermediate abundances of natural enemies compared with the untreated control and lamda-cyhalothrin.

  11. Developmental neurotoxicity of pyrethroid insecticides in zebrafish embryos.

    Science.gov (United States)

    DeMicco, Amy; Cooper, Keith R; Richardson, Jason R; White, Lori A

    2010-01-01

    Pyrethroid insecticides are one of the most commonly used residential and agricultural insecticides. Based on the increased use of pyrethroids and recent studies showing that pregnant women and children are exposed to pyrethroids, there are concerns over the potential for developmental neurotoxicity. However, there have been relatively few studies on the developmental neurotoxicity of pyrethroids. In this study, we sought to investigate the developmental toxicity of six common pyrethroids, three type I compounds (permethrin, resmethrin, and bifenthrin) and three type II compounds (deltamethrin, cypermethrin, and lambda-cyhalothrin), and to determine whether zebrafish embryos may be an appropriate model for studying the developmental neurotoxicity of pyrethroids. Exposure of zebrafish embryos to pyrethroids caused a dose-dependent increase in mortality and pericardial edema, with type II compounds being the most potent. At doses approaching the LC(50), permethrin and deltamethrin caused craniofacial abnormalities. These findings are consistent with mammalian studies demonstrating that pyrethroids are mildly teratogenic at very high doses. However, at lower doses, body axis curvature and spasms were observed, which were reminiscent of the classic syndromes observed with pyrethroid toxicity. Treatment with diazepam ameliorated the spasms, while treatment with the sodium channel antagonist MS-222 ameliorated both spasms and body curvature, suggesting that pyrethroid-induced neurotoxicity is similar in zebrafish and mammals. Taken in concert, these data suggest that zebrafish may be an appropriate alternative model to study the mechanism(s) responsible for the developmental neurotoxicity of pyrethroid insecticides and aid in identification of compounds that should be further tested in mammalian systems.

  12. Minireview: Mode of action of meta-diamide insecticides.

    Science.gov (United States)

    Nakao, Toshifumi; Banba, Shinichi

    2015-06-01

    Meta-diamides [3-benzamido-N-(4-(perfluoropropan-2-yl)phenyl)benzamides] are a distinct class of RDL GABA receptor noncompetitive antagonists showing high insecticidal activity against Spodoptera litura. The mode of action of the meta-diamides was demonstrated to be distinct from that of conventional noncompetitive antagonists (NCAs) such as fipronil, picrotoxin, lindane, dieldrin, and α-endosulfan. It was suggested that meta-diamides act at or near G336 in the M3 region of the Drosophila RDL GABA receptor. Although the site of action of the meta-diamides appears to overlap with that of macrocyclic lactones including avermectins and milbemycins, differential effects of mutations on the actions of the meta-diamides and the macrocyclic lactones were observed. Molecular modeling studies revealed that the meta-diamides may bind to an inter-subunit pocket near G336 in the Drosophila RDL GABA receptor better when in the closed state, which is distinct from the NCA-binding site, which is in a channel formed by M2s. In contrast, the macrocyclic lactones were suggested to bind to an inter-subunit pocket near G336 in the Drosophila RDL GABA receptor when in the open state. Furthermore, mechanisms underlying the high selectivity of meta-diamides are discussed. This minireview highlights the unique features of novel meta-diamide insecticides and demonstrates why meta-diamides are anticipated to become prominent insecticides that are effective against pests resistant to cyclodienes and fipronil. Copyright © 2014 Elsevier Inc. All rights reserved.

  13. Natural product derived insecticides: discovery and development of spinetoram.

    Science.gov (United States)

    Galm, Ute; Sparks, Thomas C

    2016-03-01

    This review highlights the importance of natural product research and industrial microbiology for product development in the agricultural industry, based on examples from Dow AgroSciences. It provides an overview of the discovery and development of spinetoram, a semisynthetic insecticide derived by a combination of a genetic block in a specific O-methylation of the rhamnose moiety of spinosad coupled with neural network-based QSAR and synthetic chemistry. It also emphasizes the key role that new technologies and multidisciplinary approaches play in the development of current spinetoram production strains.

  14. Hepatopancreatic intoxication of lambda cyhalothrin insecticide on albino rats

    OpenAIRE

    Elhalwagy, Manal EA; Abd-Alrahman, Sherif H; Nahas, AA; Ziada, Reem M; Mohamady, Aziza H

    2015-01-01

    Background: Despite the known adverse effects of lambda cyhalothrin insecticide, little is known about its hepatopancreatic intoxication effects. The present study was carried out to elucidate sub-chronic effect of Karat 2.5% EC formulation of lambda cyhalothrin on male albino rats. Methods: To explore the effects of exposure to lambda cyhalothrin on rats and its mechanism, low (1/40 of LD50, 5 mg/kg/day) and high dose (1/4 of LD50, 50 mg/kg/day) lambda cyhalothrin were applied to rats via dr...

  15. Cross-tolerance in amphibians: wood frog mortality when exposed to three insecticides with a common mode of action.

    Science.gov (United States)

    Hua, Jessica; Cothran, Rickey; Stoler, Aaron; Relyea, Rick

    2013-04-01

    Insecticide tolerance and cross-tolerance in nontarget organisms is often overlooked despite its potential to buffer natural systems from anthropogenic influence. We exposed wood frog tadpoles from 15 populations to three acetylcholine esterase-inhibiting insecticides and found widespread variation in insecticide tolerance and evidence for cross-tolerance to these insecticides. Our results demonstrate that amphibian populations with tolerance to one pesticide may be tolerant to many other pesticides. Copyright © 2013 SETAC.

  16. Resistance: a threat to the insecticidal crystal proteins of Bacillus thuringiensis

    Science.gov (United States)

    Leah S. Bauer

    1995-01-01

    Insecticidal crystal proteins (also known as d-endotoxins) synthesized by the bacterium Bacillus thuringiensis Berliner (Bt) are the active ingredient of various environmentally friendly insecticides that are 1) highly compatible with natural enemies and other nontarget organisms due to narrow host specificity, 2) harmless to vertebrates, 3) biodegradable in the...

  17. Effects of Nantucket pine tip moth insecticide spray schedules on loblolly pine seedlings

    Science.gov (United States)

    Christopher J. Fettig; Kenneth W. McCravy; C. Wayne Berisford

    2000-01-01

    Frequent and prolonged insecticide applications to control the Nantucket pine tip moth, Rhyacionia frustrana (Comstock) (Lepidoptera:Torticidae) (NPTM), although effective, may be impractical and uneconomica1, for commercial timber production. Timed insecticide sprays of permethrin (Polmce 3.2® EC) were applied to all possible combinations of spray...

  18. Fate and effects of the insecticide chlorpyrifos in outdoor plankton-dominated microcosms in Thailand.

    NARCIS (Netherlands)

    Daam, M.A.; Crum, S.J.H.; Brink, van den P.J.; Nogueira, A.J.A.

    2008-01-01

    The fate and effects of the insecticide chlorpyrifos were studied in plankton-dominated, freshwater microcosms in Thailand. Disappearance rates of chlorpyrifos from the water column in the present study were similar to those in temperate regions. Insecticide accumulation in the sediment was

  19. Managing fall armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae), with Bt maize and insecticides in southern Brazil.

    Science.gov (United States)

    Burtet, Leonardo M; Bernardi, Oderlei; Melo, Adriano A; Pes, Maiquel P; Strahl, Thiago T; Guedes, Jerson Vc

    2017-12-01

    Maize plants expressing insecticidal proteins of Bacillus thuringiensis are valuable options for managing fall armyworm (FAW), Spodoptera frugiperda, in Brazil. However, control failures were reported, and therefore insecticides have been used to control this species. Based on these, we evaluated the use of Bt maize and its integration with insecticides against FAW in southern Brazil. Early-planted Agrisure TL, Herculex, Optimum Intrasect and non-Bt maize plants were severely damaged by FAW and required up to three insecticidal sprays. In contrast, YieldGard VT Pro, YieldGard VT Pro 3, PowerCore, Agrisure Viptera and Agrisure Viptera 3 showed little damage and did not require insecticides. Late-planted Bt maize plants showed significant damage by FAW and required up to four sprays, with the exceptions of Agrisure Viptera and Agrisure Viptera 3. Exalt (first and second sprays); Lannate + Premio (first spray) and Avatar (second spray); and Karate + Match (first spray) and Ampligo (second spray) were the most effective insecticides against FAW larvae in Bt and non-Bt maize. Maize plants expressing Cry proteins exhibited FAW control failures in southern Brazil, necessitating insecticidal sprays. In contrast, Bt maize containing the Vip3Aa20 protein remained effective against FAW. However, regardless of the insecticide used against FAW surviving on Bt maize, grain yields were similar. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  20. Residue age and tree attractiveness influence efficacy of insecticide treatments against ambrosia beetles (Coleoptera: Curculionidae)

    Science.gov (United States)

    Management of ambrosia beetles in ornamental nurseries relies, in part, on treatments of insecticides to prevent beetles from boring into trees emitting stress-induced ethanol. However, data on residual efficacy of commonly used pyrethroid insecticides is warranted to gauge the duration that trees ...

  1. Efficacy of insecticides through contact and oral uptake towards four Agriotes wireworm species under controlled conditions

    NARCIS (Netherlands)

    Rozen, van K.; Huiting, H.F.; Wilhelm, R.; Heger, M.; Ester, A.

    2013-01-01

    Wireworms of Agriotes lineatus, A. obscurus, A. sputator and A. sordidus were exposed to insecticide treated soil using two different control methods. One method consisted of a spray application of insecticides at doses of 50, 100, 200, and 300 g a.i. per ha. The other method consisted of a bait

  2. Fate of the insecticide lambda-cyhalothrin in ditch enclosures differing in vegetation density

    NARCIS (Netherlands)

    Leistra, M.; Zweers, A.J.; Warinton, J.S.; Crum, S.J.H.; Hand, L.H.; Beltman, W.H.J.; Maund, S.J.

    2004-01-01

    Use of the insecticide lambda-cyhalothrin in agriculture may result in the contamination of water bodies, for example by spray drift. Therefore, the possible exposure of aquatic organisms to this insecticide needs to be evaluated. The exposure of the organisms may be reduced by the strong sorption

  3. Identification of insecticide residues with a conducting-polymer electronic nose

    Science.gov (United States)

    A.D. Wilson

    2014-01-01

    The identification of insecticide residues on crop foliage is needed to make periodic pest management decisions. Electronic-nose (e-nose) methods were developed and tested as a means of acquiring rapid identifications of insecticide residue types at relatively low cost by detection of headspace volatiles released from inert surfaces in vitro. Detection methods were...

  4. Influence on sensitivity to insecticides: a case study of a settled area ...

    African Journals Online (AJOL)

    The close proximity of Liwonde National Park to Liwonde town creates a unique situation of a large human population adjacent to a natural undisturbed animal reserve. The closeness of the two ecosystems has an impact on biology of mosquitoes of the area, such as susceptibility to insecticides. Susceptibility to insecticide ...

  5. Evaluation of insecticides for protecting southwestern ponderosa pines from attack by engraver beetles (Coleoptera: Curculionidae: Scolytinae)

    Science.gov (United States)

    Tom E. DeGomez; Christopher J. Hayes; John A. Anhold; Joel D. McMillin; Karen M. Clancy; Paul P. Bosu

    2006-01-01

    Insecticides that might protect pine trees from attack by engraver beetles (Ips spp.) have not been rigorously tested in the southwestern United States. We conducted two field experiments to evaluate the efficacy of several currently and potentially labeled preventative insecticides for protecting high-value ponderosa pine, Pinus ponderosa...

  6. Insecticide use in hybrid onion seed production affects pre- and postpollination processes.

    Science.gov (United States)

    Gillespie, Sandra; Long, Rachael; Seitz, Nicola; Williams, Neal

    2014-02-01

    Research on threats to pollination service in agro-ecosystems has focused primarily on the negative impacts of land use change and agricultural practices such as insecticide use on pollinator populations. Insecticide use could also affect the pollination process, through nonlethal impacts on pollinator attraction and postpollination processes such as pollen viability or pollen tube growth. Hybrid onion seed (Allium cepa L., Alliaceae) is an important pollinator-dependent crop that has suffered yield declines in California, concurrent with increased insecticide use. Field studies suggest that insecticide use reduces pollination service in this system. We conducted a field experiment manipulating insecticide use to examine the impacts of insecticides on 1) pollinator attraction, 2) pollen/stigma interactions, and 3) seed set and seed quality. Select insecticides had negative impacts on pollinator attraction and pollen/stigma interactions, with certain products dramatically reducing pollen germination and pollen tube growth. Decreased pollen germination was not associated with reduced seed set; however, reduced pollinator attraction was associated with lower seed set and seed quality, for one of the two female lines examined. Our results highlight the importance of pesticide effects on the pollination process. Overuse may lead to yield reductions through impacts on pollinator behavior and postpollination processes. Overall, in hybrid onion seed production, moderation in insecticide use is advised when controlling onion thrips, Thrips tabaci, on commercial fields.

  7. Insights from agriculture for the management of insecticide resistance in disease vectors.

    Science.gov (United States)

    Sternberg, Eleanore D; Thomas, Matthew B

    2018-04-01

    Key to contemporary management of diseases such as malaria, dengue, and filariasis is control of the insect vectors responsible for transmission. Insecticide-based interventions have contributed to declines in disease burdens in many areas, but this progress could be threatened by the emergence of insecticide resistance in vector populations. Insecticide resistance is likewise a major concern in agriculture, where insect pests can cause substantial yield losses. Here, we explore overlaps between understanding and managing insecticide resistance in agriculture and in public health. We have used the Global Plan for Insecticide Resistance Management in malaria vectors, developed under the auspices of the World Health Organization Global Malaria Program, as a framework for this exploration because it serves as one of the few cohesive documents for managing a global insecticide resistance crisis. Generally, this comparison highlights some fundamental differences between insect control in agriculture and in public health. Moreover, we emphasize that the success of insecticide resistance management strategies is strongly dependent on the biological specifics of each system. We suggest that the biological, operational, and regulatory differences between agriculture and public health limit the wholesale transfer of knowledge and practices from one system to the other. Nonetheless, there are some valuable insights from agriculture that could assist in advancing the existing Global Plan for Insecticide Resistance Management framework.

  8. Pheromone-assisted techniques to improve the efficacy of insecticide sprays against Linepithema humile (Hymenoptera: Formicidae).

    Science.gov (United States)

    Choe, Dong-Hwan; Tsai, Kasumi; Lopez, Carlos M; Campbell, Kathleen

    2014-02-01

    Outdoor residual sprays are among the most common methods for targeting pestiferous ants in urban pest management programs. If impervious surfaces such as concrete are treated with these insecticides, the active ingredients can be washed from the surface by rain or irrigation. As a result, residual sprays with fipronil and pyrethroids are found in urban waterways and aquatic sediments. Given the amount of insecticides applied to urban settings for ant control and their possible impact on urban waterways, the development of alternative strategies is critical to decrease the overall amounts of insecticides applied, while still achieving effective control of target ant species. Herein we report a "pheromone-assisted technique" as an economically viable approach to maximize the efficacy of conventional sprays targeting the Argentine ant. By applying insecticide sprays supplemented with an attractive pheromone compound, (Z)-9-hexadecenal, Argentine ants were diverted from nearby trails and nest entrances and subsequently exposed to insecticide residues. Laboratory experiments with fipronil and bifenthrin sprays indicated that the overall kill of the insecticides on Argentine ant colonies was significantly improved (57-142% increase) by incorporating (Z)-9-hexadecenal in the insecticide sprays. This technique, once it is successfully implemented in practical pest management programs, has the potential of providing maximum control efficacy with reduced amount of insecticides applied in the environment.

  9. Susceptibility of natural enemies of pests of agriculture to commonly applied insecticides in Honduras

    International Nuclear Information System (INIS)

    Bustamante, M.; Sabillon, A.; Velasquez, C.; Ordonez, J.; Baquedano, F.

    1999-01-01

    Insecticides are commonly used by Honduran farmers to control pest insects in agricultural crops such as corn, melons and tomatoes. However, the insecticides have the potential for toxicity to the natural enemies of the pest insects also. Therefore, efforts are being made to identify insecticides which, when used within the Inegerated Pest Management (IPM) programme, are selectively more toxic to the pest insects than their natural enemies. A number of selected chemical insecticides and a biological insecticide (NPV) were tested in three different tests to determine toxicity to two beneficial insects: Telenomus remus Nixon (Hymenoptera: Scelionidae) and Chrysoperla carnea Steph. (Neuroptera: Chrysopidae). All insecticides were toxic to T. remus which suffered high mortality. There was no significant difference in mortality of the insect due to the method of exposure to the insecticides. There were some differences in the toxicity of the insecticides to C. carnea, and abamectin, bifenthrin, cypermethrin, diafenthiuron, imidacloprid and fenpropathrin were relatively less toxic and could be used in IPM for the control of pest insects. (author)

  10. Insecticidal effect of furanocoumarins from fruits of Angelica archangelica L. against larvae Spodoptera littoralis Boisd

    Czech Academy of Sciences Publication Activity Database

    Pavela, R.; Vrchotová, Naděžda

    2013-01-01

    Roč. 43, MAY 2013 (2013), s. 33-39 ISSN 0926-6690 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073 Keywords : Angelica archangelica * furanocoumarins * essential oils * plant extracts * spodoptera littoralis * botanical insecticides * insecticidal activity Subject RIV: EH - Ecology, Behaviour Impact factor: 3.208, year: 2013

  11. Relative toxicity and residual activity of insecticides used in blueberry pest management: mortality of natural enemies.

    Science.gov (United States)

    Roubos, Craig R; Rodriguez-Saona, Cesar; Holdcraft, Robert; Mason, Keith S; Isaacs, Rufus

    2014-02-01

    A series of bioassays were conducted to determine the relative toxicities and residual activities of insecticides labeled for use in blueberry (Vaccinium corymbosum L.) on natural enemies, to identify products with low toxicity or short duration effects on biological control agents. In total, 14 insecticides were evaluated using treated petri dishes and four commercially available natural enemies (Aphidius colemani Viereck, Orius insidiosus [Say], Chrysoperla rufilabris [Burmeister], and Hippodamia convergens [Guérin-Menéville]). Dishes were aged under greenhouse conditions for 0, 3, 7, or 14 d before introducing insects to test residual activity. Acute effects (combined mortality and knockdown) varied by insecticide, residue age, and natural enemy species. Broad-spectrum insecticides caused high mortality to all biocontrol agents, whereas products approved for use in organic agriculture had little effect. The reduced-risk insecticide acetamiprid consistently caused significant acute effects, even after aging for 14 d. Methoxyfenozide, novaluron, and chlorantraniliprole, which also are classified as reduced-risk insecticides, had low toxicity, and along with the organic products could be compatible with biological control. This study provides information to guide blueberry growers in their selection of insecticides. Further research will be needed to determine whether adoption of a pest management program based on the use of more selective insecticides will result in higher levels of biological control in blueberry.

  12. Conjugated and fluorescent polymer based on dansyl-substituted pyrrole prepared by electrochemical polymerization in acetonitrile containing boron trifluoride diethyl etherate

    International Nuclear Information System (INIS)

    Almeida, Andresa K.A.; Dias, Jéssica M.M.; Silva, Ana Julia C.; Santos, Diego P.; Navarro, Marcelo; Tonholo, Josealdo; Goulart, Marília O.F.; Ribeiro, Adriana S.

    2014-01-01

    Graphical abstract: - Highlights: • A fluorescent pyrrole derivative bearing a dansyl substituent (PyPDG) was synthesized. • PyPDG was electropolymerized onto ITO in (C 4 H 9 ) 4 NBF 4 /CH 3 CN/BFEE mixed electrolyte. • The resulting polymer (PPyPDG) films displayed electrochromic behavior. • PPyPDG is a good green light emitter material. - Abstract: A fluorescent pyrrole derivative bearing a dansyl substituent was prepared by a simple synthetic route and electropolymerized onto Indium Tin Oxide (ITO) electrodes. The presence of the dansyl group in the monomer precursor prevents the electropolymerization in usual systems, such as (C 4 H 9 ) 4 NBF 4 in acetonitrile (CH 3 CN). For this reason, it was added 20% boron trifluoride diethyl etherate (BFEE) to this system, to achieve electropolymerization. The resulting poly[3-(N-pyrrolyl)propyl dansylglycinate] (PPyPDG) films displayed electrochromic behavior. Their color varied from greenish-yellow, in the neutral state, to greyish-green, in the oxidized state; moreover PPyPDG is a good green light emitter material. Therefore, PPyPDG films might be potentially applicable in displays and optoelectronic devices

  13. Applicability of new spin trap agent, 2-diphenylphosphinoyl-2-methyl-3,4-dihydro-2H-pyrrole N-oxide, in biological system

    International Nuclear Information System (INIS)

    Karakawa, Tomohiro; Sato, Keizo; Muramoto, Yosuke; Mitani, Yoshihiro; Kitamado, Masataka; Iwanaga, Tatsuya; Nabeshima, Tetsuji; Maruyama, Kumiko; Nakagawa, Kazuko; Ishida, Kazuhiko; Sasamoto, Kazumi

    2008-01-01

    Electron spin resonance using spin-trapping is a useful technique for detecting direct reactive oxygen species, such as superoxide (O 2 .- ). However, the widely used spin trap 2,2-dimethyl-3,4-dihydro-2H-pyrrole N-oxide (DMPO) has several fundamental limitations in terms of half-life and stability. Recently, the new spin trap 2-diphenylphosphinoyl-2-methyl-3,4-dihydro-2H-pyrrole N-oxide (DPhPMPO) was developed by us. We evaluated the biological applicability of DPhPMPO to analyze O 2 .- in both cell-free and cellular systems. DPhPMPO had a larger rate constant for O 2 .- and formed more stable spin adducts for O 2 .- than DMPO in the xanthine/xanthine oxidase (X/XO) system. In the phorbol myristate acetate-activated neutrophil system, the detection potential of DPhPMPO for O 2 .- was significantly higher than that of DMPO (k DMPO = 13.95 M -1 s -1 , k DPhPMPO = 42.4 M -1 s -1 ). These results indicated that DPhPMPO is a potentially good candidate for trapping O 2 .- in a biological system

  14. New pyrrole inhibitors of monoamine oxidase: synthesis, biological evaluation, and structural determinants of MAO-A and MAO-B selectivity.

    Science.gov (United States)

    La Regina, Giuseppe; Silvestri, Romano; Artico, Marino; Lavecchia, Antonio; Novellino, Ettore; Befani, Olivia; Turini, Paola; Agostinelli, Enzo

    2007-03-08

    A series of new pyrrole derivatives have been synthesized and evaluated for their monoamine oxidase (MAO) A and B inhibitory activity and selectivity. N-Methyl,N-(benzyl),N-(pyrrol-2-ylmethyl)amine (7) and N-(2-benzyl),N-(1-methylpyrrol-2-ylmethyl)amine (18) were the most selective MAO-B (7, SI = 0.0057) and MAO-A (18, SI = 12500) inhibitors, respectively. Docking and molecular dynamics simulations gave structural insights into the MAO-A and MAO-B selectivity. Compound 18 forms an H-bond with Gln215 through its protonated amino group into the MAO-A binding site. This H-bond is absent in the 7/MAO-A complex. In contrast, compound 7 places its phenyl ring into an aromatic cage of the MAO-B binding pocket, where it forms charge-transfer interactions. The slightly different binding pose of 18 into the MAO-B active site seems to be forced by a bulkier Tyr residue, which replaces a smaller Ile residue present in MAO-A.

  15. High content of pyridinic- and pyrrolic-nitrogen-modified carbon nanotubes derived from blood biomass for the electrocatalysis of oxygen reduction reaction in alkaline medium

    International Nuclear Information System (INIS)

    Zheng, Jie; Guo, Chaozhong; Chen, Chunyan; Fan, Mingzhi; Gong, Jianping; Zhang, Yanfang; Zhao, Tianxin; Sun, Yuelin; Xu, Xiaofan; Li, Mengmeng; Wang, Ran; Luo, Zhongli; Chen, Changguo

    2015-01-01

    Graphical abstract: Display Omitted -- Highlights: •An ORR electrocatalyst was fabricated from blood biomass and carbon nanotube. •The N-CNT catalyst exhibits good ORR activity, methanol resistance and stability. •The pyrolysis process produces high contents of pyridinic and pyrrolic N species. •The pyridinic-N group may play more important role in the active sites for ORR. -- Abstract: Here we present a facile synthetic route to design nitrogen-doped nanostructured carbon-based electrocatalyst for oxygen reduction reaction (ORR) by the copyrolysis of blood biomass from pig and carbon nanotubes (CNTs) at high temperatures. The nitrogen-doped CNTs obtained at 800 °C not only results in excellent ORR activity with four-electron transfer selectivity in alkaline medium, but also exhibits superior methanol-tolerant property and long-term stability. It is confirmed that high-temperature pyrolysis processes can facilitate to produce higher contents of pyridinic- and pyrrolic-N binding groups in electrocatalysts, contributing to the enhancement of ORR performance in terms of onset potential, half-wave potential, and limited current density. We also propose that the planar-N configuration may be the active site that is responsible for the improved ORR electrocatalytic performance. The straight-forward and cheap synthesis of the active and stable electrocatalyst makes it a promising candidate for electrochemical power sources such as fuel cells or metal-air batteries

  16. Influence of electron delocalization in heterocyclic core systems on the electrochemical communication in 2,5-di- and 2,3,4,5-tetraferrocenyl thiophenes, furans, and pyrroles.

    Science.gov (United States)

    Hildebrandt, Alexander; Schaarschmidt, Dieter; Claus, Ron; Lang, Heinrich

    2011-11-07

    A series of 2,5-di- and 2,3,4,5-tetraferrocenyl-substituted thiophenes, furans, and pyrroles were synthesized using the Negishi C,C cross-coupling protocol. The electronic and electrochemical properties of these compounds were investigated by cyclic voltammetry (CV), square wave voltammetry (SWV), and in situ UV-vis/NIR spectroscopy. The molecular structures of 2,5-diferrocenyl furan and 2,3,4,5-tetraferrocenyl-1-methyl-1H-pyrrole in the solid state are discussed. The ferrocenyls could sequentially be oxidized giving two or four reversible responses for the appropriate di- or tetraferrocenyl-substituted heterocyclic molecules. The observed ΔE°' values range between 186 and 450 mV. The NIR measurements confirm electronic communication as intervalence charge transfer (IVCT) absorptions were found in the corresponding mono- and in case of the tetraferrocenyl compounds also in the dicationic species. All compounds, except tetraferrocenyl thiophene (a class I system), were classified as class II systems according to Robin and Day. They show a linear relationship between ΔE°' and the IVCT oscillator strength f which could be shown for the first time in organometallic chemistry. This was possible because the series of molecules exhibit analogous geometries and hence, similar electrostatic properties. This correlation was confirmed by electro- and spectro-electrochemical measurements. Within these studies a new approach for the estimation of the effective electron transfer distances r(ab) is discussed. © 2011 American Chemical Society

  17. Sulfur-containing constituents and one 1H-pyrrole-2-carboxylic acid derivative from pineapple [Ananas comosus (L.) Merr.] fruit.

    Science.gov (United States)

    Zheng, Zong-Ping; Ma, Jinyu; Cheng, Ka-Wing; Chao, Jianfei; Zhu, Qin; Chang, Raymond Chuen-Chung; Zhao, Ming; Lin, Zhi-Xiu; Wang, Mingfu

    2010-12-01

    Two sulfur-containing compounds, (S)-2-amino-5-((R)-1-carboxy-2-((E)-3-(4-hydroxy-3-methoxyphenyl)allylthio)ethyl-amino)-5-oxopentanoic acid (1) and (S)-2-amino-5-((R)-1-(carboxymethylamino)-3-((E)-3-(4-hydroxyphenyl)allylthio)-1-oxopropan-2-ylamino)-5-oxopentanoic acid (2), and one 1H-pyrrole-2-carboxylic acid derivative, 6-(3-(1H-pyrrole-2-carbonyloxy)-2-hydroxypropoxy)-3,4,5-trihydroxy-tetrahydro-2H-pyran-2-carboxylic acid (3), together with eighteen known phenolic compounds, were isolated from the fruits of pineapple. Their structures were elucidated by a combination of spectroscopic analyses. Some of these compounds showed inhibitory activities against tyrosinase. The half maximal inhibitory concentration values of compounds 1, 4, 5, 6, 7 are lower than 1 mM. These compounds may contribute to the well-known anti-browning effect of pineapple juice and be potential skin whitening agents in cosmetic applications. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Pyrrolic-N-doped graphene oxide/Fe2O3 mesocrystal nanocomposite: Efficient charge transfer and enhanced photo-Fenton catalytic activity

    Science.gov (United States)

    Liu, Bing; Tian, Lihong; Wang, Ran; Yang, Jinfeng; Guan, Rong; Chen, Xiaobo

    2017-11-01

    Though α-Fe2O3 has attracted much attention in photocatalytic or Fenton-catalytic degradation of organic contaminants, its performance is still unsatisfactory due to fast recombination of electrons and holes in photocatalytic process and the difficult conversion of Fe(II) and Fe(III) in Fenton reaction. Herein, a pyrrolic N-doped graphene oxide/Fe2O3 mesocrystal (NG-Fe2O3) nanocomposite with good distribution is synthesized by a simple solvothermal method and adjusting the oxygen-containing groups on graphene oxide. The morphology of NG-Fe2O3 contributes to a relatively large BET surface area and an intimate contact between NG and Fe2O3. These two important factors along with the excellent electro-conductivity of pyrrolic-N doped GO result in the efficient separation of electron-hole pairs and fast conversion of Fe(II)and Fe(III) in photo-Fenton synergistic reaction. Thus, a remarkably improved photo-Fenton catalytic activity of NG-Fe2O3 is obtained. The degrading rate on methyl blue increases by 1.5 times and the conversion rate of glyphosate increases by 2.3 times under visible light irradiation, compared to pristine α-Fe2O3 mesocrystals.

  19. Sublethal effects of some synthetic and botanical insecticides on Bemisia tabaci (Hemiptera: Aleyrodidae

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    Esmaeily Saeideh

    2014-07-01

    Full Text Available In addition to direct mortality caused by insecticides, some biological traits of insects may also be affected by sublethal insecticide doses. In this study, we used the age-stage, two-sex life table method to evaluate the sublethal effects of the four synthetic insecticides: abamectin, imidacloprid, diazinon, and pymetrozin as well as the botanical insecticide taken from Calotropis procera (Asclepiadaceae extract, on eggs of the cotton whitefly, Bemisia tabaci (Hem.: Aleyrodidae. The lowest and highest survival rates and oviposition periods were observed in whiteflies treated by diazinon and imidacloprid, respectively. We found significant differences in the net reproductive rate (R0, the intrinsic rate of increase (r, the finite rate of increase (?, and the gross reproductive rate (GRR among different insecticides. Altogether, our results showed that pymetrozin and C. procera induced the most sublethal effects, thus they may be suitable candidates for use in integrated pest management programs of B. tabaci.

  20. Qualitative evaluation of same insecticides sold in Kinshasa and users behavior survey

    International Nuclear Information System (INIS)

    Basilua, K.; Essassi El, M.; Himmi, O.; Said Gmouh; Watsenga, T.

    2009-01-01

    Malaria is a serious public health problem in the tropical countries and particularly into Kinshasa. Anopheles gambiae sl. is the mean vector of this illness. The use of impregnated bednets is the national strategy; the chemical insecticides are used too in figthing the malaria vectors. The survey carried out on 144 households randomly selected in Kinshasa have showed that 61,1% are favourable with using bednets insecticide impregnated and 96,5% of these households use too chemical insecticides, meanly the pyrethroids one (90,5%) and the organophosphates (9,5%). Mass spectrometer analysis revealed that 87,5% of identified insecticides, essentially pyrethroinids have tetramethrine as active substance; the dichlorvos is the only one to be detected as organophosphate and that in some insecticides, the detected molecules are not avowed or different from those avowed or different from those avowed by the manufacturer.

  1. Molecular Descriptors Family on Structure Activity Relationships 2. Insecticidal Activity of Neonicotinoid Compounds

    Directory of Open Access Journals (Sweden)

    Sorana BOLBOACĂ

    2005-01-01

    Full Text Available The neonicotinoids are the newest major class of insecticides modeled after the basic nicotine molecule having improved insecticide activity and generally low toxicity. The insecticidal activities of neonicotinoids were previous studied using 3D and standard partial least squares regression models. The paper describes the ability of the MDF SAR methodology in prediction of insecticidal activities of neonicotinoid compounds. The best MDF SAR bi-varied model was validated on training and test sets and its ability on prediction of insecticidal activity was compared with previous reported models. Even if the MDF SAR methodology is complex and time consuming the results worth the effort because they are statistical significant better then previous reported results.

  2. Effects of various insecticides on the development of the egg parasitoid Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae).

    Science.gov (United States)

    Takada, Y; Kawamura, S; Tanaka, T

    2001-12-01

    The toxicity of six insecticides, acephate, methomyl, ethofenprox, cartap, chlorfluazuron, and Bacillus thuringiensis (Bt) was tested on different developmental stages of the egg parasitoid, Trichogramma dendrolimi (Matsumura). Each of the insecticides tested showed different degrees of toxicity to the parasitoid, Ethofenprox showed the highest toxicity and cartap showed relatively higher toxicity compared with the other insecticides. The development of the parasitoids treated with these two insecticides was normal, similar to that of the control group. Only the emergence of adult wasps from host eggs was disturbed. Emergence of the host, Mamestra brassicae larva was reduced following treatment with ethofenprox, cartap and methomyl. However, adult female wasps, which emerged from host eggs treated with the insecticides had the ability to oviposit normally.

  3. Insecticide treated curtains and residual insecticide treatment to control Aedes aegypti: An acceptability study in Santiago de Cuba.

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    Dennis Pérez

    2018-01-01

    Full Text Available Within the context of a field trial conducted by the Cuban vector control program (AaCP, we assessed acceptability of insecticide-treated curtains (ITCs and residual insecticide treatment (RIT with deltamethrin by the community. We also assessed the potential influence of interviewees' risk perceptions for getting dengue and disease severity.We embedded a qualitative study using in-depth interviews in a cluster randomized trial (CRT testing the effectiveness of ITCs and RIT in Santiago de Cuba. In-depth interviews (N = 38 were conducted four and twelve months after deployment of the tools with people who accepted the tools, who stopped using them and who did not accept the tools. Data analysis was deductive. Main reasons for accepting ITCs at the start of the trial were perceived efficacy and not being harmful to health. Constraints linked to manufacturer instructions were the main reason for not using ITCs. People stopped using the ITCs due to perceived allergy, toxicity and low efficacy. Few heads of households refused RIT despite the noting reasons for rejection, such as allergy, health hazard and toxicity. Positive opinions of the vector control program influenced acceptability of both tools. However, frequent insecticide fogging as part of routine AaCP vector control actions diminished perceived efficacy of both tools and, therefore, acceptability. Fifty percent of interviewees did feel at risk for getting dengue and considered dengue a severe disease. However, this did not appear to influence acceptability of ITCs or RIT.Acceptability of ITCs and RIT was linked to acceptability of AaCP routine vector control activities. However, uptake and use were not always an indication of acceptability. Factors leading to acceptability may be best identified using qualitative methods, but more research is needed on the concept of acceptability and its measurement.

  4. Insecticide treated curtains and residual insecticide treatment to control Aedes aegypti: An acceptability study in Santiago de Cuba.

    Science.gov (United States)

    Pérez, Dennis; Van der Stuyft, Patrick; Toledo, María Eugenia; Ceballos, Enrique; Fabré, Francisco; Lefèvre, Pierre

    2018-01-01

    Within the context of a field trial conducted by the Cuban vector control program (AaCP), we assessed acceptability of insecticide-treated curtains (ITCs) and residual insecticide treatment (RIT) with deltamethrin by the community. We also assessed the potential influence of interviewees' risk perceptions for getting dengue and disease severity. We embedded a qualitative study using in-depth interviews in a cluster randomized trial (CRT) testing the effectiveness of ITCs and RIT in Santiago de Cuba. In-depth interviews (N = 38) were conducted four and twelve months after deployment of the tools with people who accepted the tools, who stopped using them and who did not accept the tools. Data analysis was deductive. Main reasons for accepting ITCs at the start of the trial were perceived efficacy and not being harmful to health. Constraints linked to manufacturer instructions were the main reason for not using ITCs. People stopped using the ITCs due to perceived allergy, toxicity and low efficacy. Few heads of households refused RIT despite the noting reasons for rejection, such as allergy, health hazard and toxicity. Positive opinions of the vector control program influenced acceptability of both tools. However, frequent insecticide fogging as part of routine AaCP vector control actions diminished perceived efficacy of both tools and, therefore, acceptability. Fifty percent of interviewees did feel at risk for getting dengue and considered dengue a severe disease. However, this did not appear to influence acceptability of ITCs or RIT. Acceptability of ITCs and RIT was linked to acceptability of AaCP routine vector control activities. However, uptake and use were not always an indication of acceptability. Factors leading to acceptability may be best identified using qualitative methods, but more research is needed on the concept of acceptability and its measurement.

  5. Preparation and microwave absorbing properties of nickel-coated graphite nanosheet with pyrrole via in situ polymerization

    International Nuclear Information System (INIS)

    Yang Yongqing; Qi Shuhua; Wang Jianning

    2012-01-01

    Highlights: ► NanoG was prepared and chemically coated by nano-Ni. ► PPy/NanoG and PPy/Ni/NanoG were prepared via in situ polymerization. ► The samples were characterized by SEM, XRD, EDS and FTIR. ► PPy/NanoG and PPy/Ni/NanoG exhibit good electromagnetic properties. - Abstract: Nanocomposites PPy/NanoG and PPy/Ni/NanoG were prepared via in situ polymerization of pyrrole in the presence of NanoG and nickel-coated graphite nanosheet (Ni/NanoG), respectively. The morphologies and nanostructures of NanoG, Ni/NanoG, PPy, PPy/NanoG and PPy/Ni/NanoG were characterized by scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), Fourier transmission infrared (FTIR) and X-ray diffraction analysis (XRD). Results show that most of PPy chains disperse on NanoG and Ni/NanoG's surfaces for the high aspect ratio (300–500) of NanoG and Ni/NanoG. From the thermogravimetric analysis (TG) it can be seen that the introduction of Ni and NanoG leads the composites PPy/NanoG and PPy/Ni/NanoG to exhibit a better thermal stability than pure PPy. According to the four-point-probe test, the conductivities of the final PPy/NanoG and PPy/Ni/NanoG composites are dramatically increased compared to pure PPy. Measurement of electromagnetic parameters shows that the reflection loss (R) of PPy/Ni/NanoG is below −19 dB at the X band (8.2–12.4 GHz) and the minimum loss value is −23.46 dB at 9.88 GHz. The reflection loss of PPy/NanoG is below −10 dB at 8.2–12.4 GHz and the minimum loss value is −13.44 dB at 10.28 GHz. The microwave absorbing properties of PPy/NanoG and PPy/Ni/NanoG are superior to those of PPy.

  6. Green Synthesis of Ag and Pd Nanospheres, Nanowires, and Nanorods Using Vitamin B2: Catalytic Polymerisation of Aniline and Pyrrole

    Directory of Open Access Journals (Sweden)

    Mallikarjuna N. Nadagouda

    2008-01-01

    Full Text Available For the first time, we report green chemistry approach using vitamin B2 in the synthesis of silver (Ag and palladium (Pd, nanospheres, nanowires, and nanorods at room temperature without using any harmful reducing agents, such as sodium borohydride (NaBH4 or hydroxylamine hydrochloride and any special capping or dispersing agent. Vitamin B2 was used as reducing agent as well as capping agent due to its high-water solubility, biodegradability, and low-toxicity compared with other reducing agents. The average particle size of nanoprticle was found to be Ag (average size 6.1±0.1 nm and Pd (average size 4.1±0.1 nm nanoparticles in ethylene glycol and Ag (average size 5.9±0.1 nm, and average size 6.1±0.1 nanoparticles in acetic acid and NMP, respectively. The formation of noble multiple shape nanostructures and their self assembly were dependent on the solvent employed for the preparation. When water was used as solvent media, Ag and Pd nanoparticles started to self-assemble into rod-like structures and in isopropanol Ag and Pd nanoparticles yielded wire-like structures with a thickness in the range of 10 to 20 nm and several hundred microns in length. In acetone and acetonitrile medium, the Ag and Pd nanoparticles are self-assembled into a regular pattern making nanorod structures with thicknesses ranging from 100 to 200 nm and lengths of a few microns. The so-synthesized nanostructures were characterized using scanning electron microscopy (SEM, transmission electron microscopy (TEM, energy dispersive X-ray (EDX analysis, and UV spectroscopy. The ensuing Ag and Pd nanoparticles catalyzed the reactions of aniline and pyrrole to generate polyaniline and polypyrrole nanofibers and may find various technological and biological applications. This single-step greener approach is general and can be extended to other noble metals and transition metal oxides.

  7. Blood pyrrole-protein adducts as a diagnostic and prognostic index in pyrrolizidine alkaloid-hepatic sinusoidal obstruction syndrome.

    Science.gov (United States)

    Gao, Hong; Ruan, Jianqing Q; Chen, Jie; Li, Na; Ke, Changqiang Q; Ye, Yang; Lin, Ge; Wang, Jiyao Y

    2015-01-01

    The diagnosis of hepatic sinusoidal obstruction syndrome (HSOS) induced by pyrrolizidine alkaloids is mainly based on clinical investigation. There is currently no prognostic index. This study evaluated the quantitative measurement of blood pyrrole-protein adducts (PPAs) as a diagnostic and prognostic index for pyrrolizidine alkaloid-induced HSOS. Suspected drug-induced liver injury patients were prospectively recruited. Blood PPAs were quantitatively measured using ultra-performance liquid chromatography-tandem mass spectrometry. Patients' age, sex, biochemistry test results, and a detailed drug history were recorded. The patients were divided into two groups, ie, those with HSOS induced by pyrrolizidine alkaloid-containing drugs and those with liver injury induced by drugs without pyrrolizidine alkaloids. The relationship between herb administration, clinical outcomes, blood sampling time, and blood PPA concentration in pyrrolizidine alkaloid-associated HSOS patients was analyzed using multiple linear regression analysis. Forty patients met the entry criteria, among whom 23 had pyrrolizidine alkaloid-associated HSOS and 17 had liver injury caused by drugs without pyrrolizidine alkaloids. Among the 23 patients with pyrrolizidine alkaloid-associated HSOS, ten recovered, four developed chronic disease, eight died, and one underwent liver transplantation within 6 months after onset. Blood PPAs were detectable in 24 of 40 patients with concentrations from 0.05 to 74.4 nM. Sensitivity and specificity of the test for diagnosis of pyrrolizidine alkaloid-associated HSOS were 100% (23/23) and 94.1% (23/24), respectively. The positive predictive value was 95.8% and the negative predictive value was 100%, whereas the positive likelihood ratio was 23.81. The level of blood PPAs in the severe group (died or received liver transplantation) was significantly higher than that in the recovery/chronicity group (P=0.004). Blood PPAs measured by ultra-performance liquid

  8. Stability of the 14 C-Radiolabelled insecticide guthion

    International Nuclear Information System (INIS)

    Fakhr, I.M.I.; Shaheen, F.A.; Hazzaa, N.I.; Hamdy, N.A.

    1993-01-01

    Under variable conditions simulating those of the agricultural practice, the effects of temperature and PH variations on the stability of 14 C-guthion have been studied. It was found that the insecticide is fairly stable in the acid medium and the half-life of the compound reached 230 days at 25 degree C and declined to about 7 days at 54 degree C, but in the alkaline medium, the degradation rate clearly increased as the PH increased and the half-life reached 24 hours in PH 11 at 25 degree C. In the neutral medium, the half-life was about eight days at 25 degree C while at 54 degree C, it was three days. The insecticide decomposed rapidly as the temperature was raised and the rate was much increased by the combined increase in heat and alkalinity. Some of the degradation products were identified as: O,O-dimethylthio- and di thiophosphoric acid, 4-O x O-3,4-dihydro, 1,2,3-benzo triazine and its hydroxymethyl derivative. 2 figs., 1 tab

  9. Synthesis and Insecticidal Activity of an Oxabicyclolactone and Novel Pyrethroids

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    Elson S. de Alvarenga

    2012-11-01

    Full Text Available Deltamethrin, a member of the pyrethroids, one of the safest classes of pesticides, is among some of the most popular and widely used insecticides in the World. Our objective was to synthesize an oxabicyclolactone 6 and five novel pyrethroids 8–12 from readily available furfural and D-mannitol, respectively, and evaluate their biological activity against four insect species of economic importance namely A. obtectus, S. zeamais, A. monuste orseis, and P. americana. A concise and novel synthesis of 6,6-dimethyl-3-oxabicyclo[3.1.0]hexan-2-one (6 from furfural is described. Photochemical addition of isopropyl alcohol to furan-2(5H-one afforded 4-(1'-hydroxy-1'-methylethyltetrahydro-furan-2-one (3. The alcohol 3 was directly converted into 4-(1'-bromo-1'-methylethyl-tetrahydrofuran-2-one (5 in 50% yield by reaction with PBr3 and SiO2. The final step was performed by cyclization of 5 with potassium tert-butoxide in 40% yield. The novel pyrethroids 8–12 were prepared from methyl (1S,3S-3-formyl-2,2-dimethylcyclopropane-1-carboxylate (7a by reaction with five different aromatic phosphorous ylides. Compounds 6–12 presented high insecticidal activity, with 6 and 11 being the most active. Compound 6 killed 90% of S. zeamais and 100% of all the other insects evaluated. Compound 11 killed 100% of all insects tested.

  10. Actions of insecticides on the insect GABA receptor complex

    International Nuclear Information System (INIS)

    Bermudez, I.; Hawkins, C.A.; Taylor, A.M.; Beadle, D.J.

    1991-01-01

    The actions of insecticides on the insect gamma-aminobutyric acid (GABA) receptor were investigated using [35S]t-butylbicyclophosphorothionate [( 35S]TBPS) binding and voltage-clamp techniques. Specific binding of [35S]TBPS to a membrane homogenate derived from the brain of Locusta migratoria locusts is characterised by a Kd value of 79.3 ± 2.9 nM and a Bmax value of 1770 ± 40 fmol/mg protein. [35S]TBPS binding is inhibited by mM concentrations of barbiturates and benzodiazepines. In contrast dieldrin, ivermectin, lindane, picrotoxin and TBPS are inhibitors of [35S]TBPS binding at the nanomolar range. Bicuculline, baclofen and pyrethroid insecticides have no effect on [35S]TBPS binding. These results are similar to those obtained in electrophysiological studies of the current elicited by GABA in both Locusta and Periplaneta americana central neurones. Noise analysis of the effects of lindane, TBPS, dieldrin and picrotoxin on the cockroach GABA responses reveals that these compounds decrease the variance of the GABA-induced current but have no effect on its mean open time. All these compounds, with the exception of dieldrin, significantly decrease the conductance of GABA-evoked single current

  11. Evolution of Bacillus thuringiensis Cry toxins insecticidal activity.

    Science.gov (United States)

    Bravo, Alejandra; Gómez, Isabel; Porta, Helena; García-Gómez, Blanca Ines; Rodriguez-Almazan, Claudia; Pardo, Liliana; Soberón, Mario

    2013-01-01

    Insecticidal Cry proteins produced by Bacillus thuringiensis are use worldwide in transgenic crops for efficient pest control. Among the family of Cry toxins, the three domain Cry family is the better characterized regarding their natural evolution leading to a large number of Cry proteins with similar structure, mode of action but different insect specificity. Also, this group is the better characterized regarding the study of their mode of action and the molecular basis of insect specificity. In this review we discuss how Cry toxins have evolved insect specificity in nature and analyse several cases of improvement of Cry toxin action by genetic engineering, some of these examples are currently used in transgenic crops. We believe that the success in the improvement of insecticidal activity by genetic evolution of Cry toxins will depend on the knowledge of the rate-limiting steps of Cry toxicity in different insect pests, the mapping of the specificity binding regions in the Cry toxins, as well as the improvement of mutagenesis strategies and selection procedures. © 2012 The Authors. Microbial Biotechnology © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  12. Dog poisoning with furadan 35-ST (carbamate insecticide

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    Aleksić Jelena

    2011-01-01

    Full Text Available The first case of poisoning of a dog with Furadan 35-ST in Serbia is described. The active ingredient of Furadan 35-ST is carbofuran (2,3-dihydro-2,2-dimethyl-7- benzofuranyl methyl carbamate, a carbamate insecticide, acaricide and nematocide. This highly poisonous substance is classified by the World Health Organisation into Class 1 b and in Serbia into Group 1 of The List of Poisons. Pathological assessment revealed hyperaemia and degenerative and necrotic changes in the liver, kidneys and heart. In addition, lysis of the nuclei in the motor neurons, loss of tigroid substance and pericellular oedema in the ventral horns of the spinal cord, and acute pancreatitis were found. In addition to the non-specific changes (hyperaemia, degenerative and necrotic changes in the parenchymal organs, the ones in the ventral horns of the spinal cord and acute pancreatitis may lead to carbamate poisoning being suspected. The diagnosis was established on the grounds of toxicological-chemical conformation of carbofuran by means of GC-MS in addition to the macroscopic, microscopic findings in tissue samples taken from the stomach and the liver, which confirmed the suspicion of the dog having been poisoned with the carbamate insecticide. In the current case the results of the diagnostic procedures provided foundations for the initiation of criminal proceedings.

  13. Volatile aldehydes are promising broad-spectrum postharvest insecticides.

    Science.gov (United States)

    Hammond, D G; Rangel, S; Kubo, I

    2000-09-01

    A variety of naturally occurring aldehydes common in plants have been evaluated for their insecticidal activity and for phytotoxicity to postharvest fruits, vegetables, and grains. Twenty-nine compounds were initially screened for their activity against aphids on fava bean leaf disks. Application under reduced pressure (partial vacuum) for the first quarter of fumigation increased insecticidal activity severalfold. The 11 best aldehydes were assayed against aphids placed under the third leaf of whole heads of iceberg lettuce using the same two-tier reduced-pressure regime, which caused no additional detriment to the commodity over fumigation at atmospheric pressure. Phytotoxicity to naked and wrapped iceburg lettuce, green and red table grapes, lemon, grapefruit, orange, broccoli, avocado, cabbage, pinto bean, and rice at doses that killed 100% of aphids was recorded for three promising fumigants: propanal, (E)-2-pentenal, and 2-methyl-(E)-2-butenal. These three compounds have excellent potential as affordable postharvest insect control agents, killing 100% of the aphids with little or no detectable harm to a majority of the commodities tested. Preliminary assays indicate that similar doses are also effective against mealybugs, thrips, and whitefly.

  14. Pyrethroid insecticides evoke neurotransmitter release from rabbit striatal slices

    International Nuclear Information System (INIS)

    Eells, J.T.; Dubocovich, M.L.

    1988-01-01

    The effects of the synthetic pyrethroid insecticide fenvalerate ([R,S]-alpha-cyano-3-phenoxybenzyl[R,S]-2-(4-chlorophenyl)-3- methylbutyrate) on neurotransmitter release in rabbit brain slices were investigated. Fenvalerate evoked a calcium-dependent release of [ 3 H]dopamine and [ 3 H]acetylcholine from rabbit striatal slices that was concentration-dependent and specific for the toxic stereoisomer of the insecticide. The release of [ 3 H]dopamine and [ 3 H]acetylcholine by fenvalerate was modulated by D2 dopamine receptor activation and antagonized completely by the sodium channel blocker, tetrodotoxin. These findings are consistent with an action of fenvalerate on the voltage-dependent sodium channels of the presynaptic membrane resulting in membrane depolarization, and the release of dopamine and acetylcholine by a calcium-dependent exocytotic process. In contrast to results obtained in striatal slices, fenvalerate did not elicit the release of [ 3 H]norepinephrine or [ 3 H]acetylcholine from rabbit hippocampal slices indicative of regional differences in sensitivity to type II pyrethroid actions

  15. Efficacy of Selected Insecticide Sprays and Aerosols against the Common Bed Bug, Cimex lectularius (Hemiptera: Cimicidae

    Directory of Open Access Journals (Sweden)

    Changlu Wang

    2016-01-01

    Full Text Available We evaluated the residual efficacy of four liquid sprays and four ready-to-use aerosols that are commonly used in the U.S. against a field-collected bed bug, Cimex lectularius L., strain with moderate resistance level to pyrethroids. The four liquid sprays were: Tandem (0.1% thiamethoxam, 0.03% lambda-cyhalothrin, Temprid SC (0.05% imidacloprid, 0.025% cyfluthrin, Transport GHP (0.05% acetamiprid, 0.06% bifenthrin, and Demand CS (0.03% lambda-cyhalothrin. The four aerosols were: Alpine (0.5% dinotefuran, Bedlam (0.4% sumithrin, 1.6% MGK 264, Bedlam Plus (0.4% sumithrin, 1% MGK 264, 0.05% imidacloprid, and Phantom (0.5% chlorfenapyr. Bed bugs were confined for 4 h to treated substrates (aged 24 h. Four substrates were tested: fabric, unpainted wood, painted wood, and vinyl. Bedlam, Demand CS, and Temprid SC resulted in ≤70% mortality on all tested substrates. Among the other five products, substrate type significantly affected their residual efficacy, except for Transport GHP, which caused ≥89.7% mortality regardless of the substrate. The effect of exposure time (5 min, 4 h, and 24 h on the efficacy of Transport GHP and Phantom aerosol also was evaluated. A 4 h continuous exposure to Phantom aerosol or Transport GHP residue caused similar mortality to 24 h exposure and higher mortality than 5 min exposure.

  16. Ordering effects in benzo[1,2-b:4,5-b']difuran-thieno[3,4-c]pyrrole-4,6- dione polymers with >7% solar cell efficiency

    KAUST Repository

    Warnan, Julien; Cabanetos, Clement; El Labban, Abdulrahman; Hansen, Michael Ryan; Tassone, Christopher J.; Toney, Michael F.; Beaujuge, Pierre

    2014-01-01

    Benzo[1,2-b:4,5-b']difuran-thieno[3,4-c]pyrrole-4,6-dione (PBDFTPD) polymers prepared by microwave-assisted synthesis can achieve power conversion efficiencies (PCEs) >7% in bulk-heterojunction solar cells with phenyl-C61/71-butyric acid methyl

  17. Electron-deficient N-alkyloyl derivatives of thieno[3,4-c]pyrrole-4,6-dione yield efficient polymer solar cells with open-circuit voltages > 1 v

    KAUST Repository

    Warnan, Julien; Cabanetos, Clement; Bude, Romain; El Labban, Abdulrahman; LI, LIANG; Beaujuge, Pierre

    2014-01-01

    Poly(benzo[1,2-b:4,5-b′]dithiophene-thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) polymer donors yield some of the highest open-circuit voltages (V OC, ca. 0.9 V) and fill factors (FF, ca. 70%) in conventional bulk-heterojunction (BHJ) solar cells

  18. Linear side chains in benzo[1,2-b:4,5-b′]dithiophene-thieno[3,4-c] pyrrole-4,6-dione polymers direct self-assembly and solar cell performance

    KAUST Repository

    Cabanetos, Clement; El Labban, Abdulrahman; Bartelt, Jonathan A.; Douglas, Jessica D.; Mateker, William R.; Frechet, Jean; McGehee, Michael D.; Beaujuge, Pierre

    2013-01-01

    role that linear side-chain substituents play in poly(benzo[1,2-b:4,5-b′]dithiophene-thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) polymers for bulk heterojunction (BHJ) solar cell applications. We show that replacing branched side chains by linear ones

  19. Development of Environment-Friendly Insecticides Based on Enantioselectivity: Bifenthrin as a Case.

    Science.gov (United States)

    Qian, Yi; Zhou, Peixue; Zhang, Quan

    2017-01-01

    Chiral insecticides significantly contribute to the environmental pollutions recently. As the development of industry and agriculture, increasing number of chiral insecticides are to be introduced into the market. However, their enantioselective toxicology to ecosystem still remains uncertain. In this review, we embarked on a structured search of bibliographic databases for peer-reviewed articles regarding the enantioselective effects of bifenthrin, a typical chiral insecticide, on both target and non-target species. With this enantioselective property of chiral insecticides, they often exhibit adverse effects on non-target species enantioselectively. Specifically, the enantioselective effects of bifenthrin on target and non-target organisms were discussed. In target species, R-bifenthrin exerts more significant activities in deinsectization, compared with S-bifenthrin. On the other hand, Sbifenthrin is more toxic to non-target species than R-bifenthrin, which suggests that the application of sole enantiomer is more efficient and environment-friendly than that of racemate. This review confirms the choice of environment-friendly insecticides from the perspective of the enantioselectivity of chiral insecticides. To make insecticides more efficient to target species and less toxic to non-target species, further research should be done to investigated the potential effects of targetactive enantiomers on non-target organisms as well as the enantioselective fate of enantiomers in multiple environmental matrix.

  20. Toxicity of insecticides to the sweetpotato whitefly (Hemiptera: Aleyrodidae) and its natural enemies.

    Science.gov (United States)

    Bacci, Leandro; Crespo, André L B; Galvan, Tederson L; Pereira, Eliseu J G; Picanço, Marcelo C; Silva, Gerson A; Chediak, Mateus

    2007-07-01

    Efficient chemical control is achieved when insecticides are active against insect pests and safe to natural enemies. In this study, the toxicity of 17 insecticides to the sweetpotato whitefly, Bemisia tabaci (Gennadius), and the selectivity of seven insecticides to natural enemies of this insect pest were evaluated. To determine the insecticide toxicity, B. tabaci adults were exposed to abamectin, acephate, acetamiprid, cartap, imidacloprid, malathion, methamidophos, bifenthrin, cypermethrin, deltamethrin, esfenvalerate, fenitrothion, fenpropathrin, fenthion, phenthoate, permethrin and trichlorphon at 50 and 100% of the field rate (FR), and to water (untreated control). To determine the insecticide selectivity, adults of Encarsia sp., Acanthinus sp., Discodon sp. and Lasiochilus sp. were exposed to abamectin, acephate, acetamiprid, cartap, imidacloprid, malathion and methamidophos at 50 and 100% FR, and to water. Groups of each insect species were exposed to kale leaves preimmersed in each treatment under laboratory conditions. Mortality of exposed individuals was recorded 24 h after treatment. Cartap and imidacloprid at 50 and 100% FR and abamectin and acetamiprid at 100% FR showed insecticidal activity to B. tabaci adults. Abamectin at 50 and 100% FR was the least insecticidal compound to the natural enemies Acanthinus sp., Discodon sp. and Lasiochilus sp. The present results suggest that abamectin at 100% FR may decrease B. tabaci field populations but can still be harmless to predators. Implications of these results within an integrated pest management context are discussed. Copyright (c) 2007 Society of Chemical Industry.

  1. The response of natural enemies to selective insecticides applied to soybean.

    Science.gov (United States)

    Varenhorst, A J; O'Neal, M E

    2012-12-01

    Natural enemies of the invasive pest Aphis glycines Matsumura can prevent its establishment and population growth. However, current A. glycines management practices include the application of broad-spectrum insecticides that affect pests and natural enemies that are present in the field at the time of application. An alternative is the use of selective insecticides that affect the targeted pest species, although having a reduced impact on the natural enemies. We tested the effects of esfenvalerate, spirotetramat, imidacloprid, and a combination of spirotetramat and imidacloprid on the natural enemies in soybean during the 2009 and 2010 field season. The natural enemy community that was tested differed significantly between 2009 and 2010 (F = 87.41; df = 1, 598; P natural enemy in 2009 was Harmonia axyridis (Pallas) (56.0%) and in 2010 was Orius insidiosus (Say) (41.0%). During 2009, the abundance of natural enemies did not vary between the broad-spectrum and selective insecticides; however, the abundance of natural enemies was reduced by all insecticide treatments when compared with the untreated control. In 2010, the selective insecticide imidacloprid had more natural enemies than the broad-spectrum insecticide. Although we did not observe a difference in the abundance of the total natural enemy community in 2009, we did observe more H. axyridis in plots treated with spirotetramat. In 2010, we observed more O. insidiosus in plots treated with imidacloprid. We suggest a couple of mechanisms to explain how the varying insecticides have different impacts on separate components of the natural enemy community.

  2. Development, oviposition, and mortality of Neoseiulus fallacis (Acari: Phytoseiidae) in response to reduced-risk insecticides.

    Science.gov (United States)

    Villanueva, Raul T; Walgenbach, James F

    2005-12-01

    Eight reduced-risk insecticides (acetamiprid, thiamethoxam, imidacloprid, thiacloprid, methoxyfenozide, pyriproxyfen, indoxacarb, and spinosad) and three conventional insecticides (azinphosmethyl, fenpropathrin, and esfenvalerate) were tested against Neoseiulus fallacis (Garman) (Acari: Phytoseiidae), the most abundant predacious mite in North Carolina apple (Malus spp.) orchards. To assess the effect of insecticides on development and mortality of N. fallacis immatures, 12-h-old eggs were individually placed on bean leaf disks previously dipped in insecticide solutions. Tetranychus urticae Koch (Acari: Tetranychidae) females were added as a food source. None of the reduced-risk insecticides significantly affected immature N. fallacis compared with the control; however, the pyrethroids esfenvalerate and fenpropathrin were highly toxic to immatures. To evaluate the effect of insecticides on mortality and oviposition of adult N. fallacis, 7- to 8-d-old females were confined on insecticide-treated bean leaves with Malephora crocea (Aizoaceae) pollen added as a food source. Spinosad resulted in the highest mortality, whereas azinphosmethyl, acetamiprid, fenpropathrin, and imidacloprid were moderately toxic, and mortality from esfenvalerate, indoxacarb, thiacloprid, methoxyfenozide, pyriproxyfen, and thiamethoxam did not differ significantly from the control. Oviposition was affected in a similar manner, with the exception of acetamiprid that did not affect oviposition, and thiamethoxam that reduced oviposition.

  3. Susceptibility of pest Nezara viridula (Heteroptera: Pentatomidae) and parasitoid Trichopoda pennipes (Diptera: Tachinidae) to selected insecticides.

    Science.gov (United States)

    Tillman, P Glynn

    2006-06-01

    Susceptibility of the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae), and its endoparasitoid Trichopoda pennipes (F.) (Diptera: Tachinidae) to acetamiprid, cyfluthrin, dicrotophos, indoxacarb, oxamyl, and thiamethoxam was compared in residual and oral toxicity tests. In the residual toxicity test, cyfluthrin, dicrotophos, and oxamyl were highly toxic to N. viridula. Thiamethoxam was moderately toxic to these insects. Each of the four insecticides was highly toxic to T. pennipes after prolonged tarsal contact with dried residues of these chemicals. In the oral toxicity test, where N. viridula fed on food covered with insecticide residues, none of the insecticides were toxic to adults of this stink bug, but acetamiprid, dicrotophos, and thiamethoxam were moderately toxic to the nymphs. In the oral toxicity test, where N. viridula fed on a gel-food containing insecticides, cyfluthrin, dicrotophos, oxamyl, and thiamethoxam were highly toxic to this stink bug. In an oral toxicity test using contaminated sugar water, all of the insecticides were highly toxic to T. pennipes. Because insecticides were as toxic, or more toxic, to T. pennipes than to N. viridula, it is extremely important to conserve this parasitoid by applying these insecticides for control of southern green stink bugs only when the pest reaches economic threshold.

  4. Environmental risk assessment of registered insecticides in Iran using Environmental Impact Quotient (EIQ index

    Directory of Open Access Journals (Sweden)

    S. Moinoddini

    2016-05-01

    Full Text Available In the last decades, pesticides have been used extensively, in order to control pests and plant diseases, but negative impacts of pesticides caused several environmental problems and put human health in danger. In order to decrease environmental hazards of pesticide, risk of pesticide application should be measured briefly and precisely. In this study environmental impacts of registered insecticides in Iran which applied in 2001-2002, 2003-2004, 2004-2005, are considered using environmental impact quotient (EIQ index. Results showed that among considered insecticides, Imidacloprid, Fipronil and Tiodicarb, potentially (EIQ were the most hazardous insecticides, respectively. Taking rate of application and active ingredient of insecticide in to account, environmental impact (practical toxicity per cultivated hectare (EIQ Field of each provinces were investigated. In this regard, among different province of Iran, Kerman, Mazandaran and Golestan were in danger more than the others, respectively. Besides, considering the amount of agricultural production in provinces, environmental impact per ton of production were calculated for each provinces which three northern provinces of Mazandaran, Golestan and Guilan, respectively endure the most environmental impact per ton of production. Eventually based on environmental impact quotient, results demonstrated that majority of environmental impacts of insecticide in Iran were due to inadequate knowledge and also overuse of a few number of insecticides. Therefore, by improving knowledge about environmental impact of pesticides and also developing environmental friendly and ecological based methods, negative environmental impacts of insecticides will be reduced significantly.

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

    Science.gov (United States)

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

    2013-07-01

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

  6. Insecticide resistance, control failure likelihood and the First Law of Geography.

    Science.gov (United States)

    Guedes, Raul Narciso C

    2017-03-01

    Insecticide resistance is a broadly recognized ecological backlash resulting from insecticide use and is widely reported among arthropod pest species with well-recognized underlying mechanisms and consequences. Nonetheless, insecticide resistance is the subject of evolving conceptual views that introduces a different concept useful if recognized in its own right - the risk or likelihood of control failure. Here we suggest an experimental approach to assess the likelihood of control failure of an insecticide allowing for consistent decision-making regarding management of insecticide resistance. We also challenge the current emphasis on limited spatial sampling of arthropod populations for resistance diagnosis in favor of comprehensive spatial sampling. This necessarily requires larger population sampling - aiming to use spatial analysis in area-wide surveys - to recognize focal points of insecticide resistance and/or control failure that will better direct management efforts. The continuous geographical scale of such surveys will depend on the arthropod pest species, the pattern of insecticide use and many other potential factors. Regardless, distance dependence among sampling sites should still hold, following the maxim that the closer two things are, the more they resemble each other, which is the basis of Tobler's First Law of Geography. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  7. Cytochrome P450s--Their expression, regulation, and role in insecticide resistance.

    Science.gov (United States)

    Liu, Nannan; Li, Ming; Gong, Youhui; Liu, Feng; Li, Ting

    2015-05-01

    P450s are known to be critical for the detoxification and/or activation of xenobiotics such as drugs and pesticides and overexpression of P450 genes can significantly affect the disposition of xenobiotics in the tissues of organisms, altering their pharmacological/toxicological effects. In insects, P450s play an important role in detoxifying exogenous compounds such as insecticides and plant toxins and their overexpression can result in increased levels of P450 proteins and P450 activities. This has been associated with enhanced metabolic detoxification of insecticides and has been implicated in the development of insecticide resistance in insects. Multiple P450 genes have been found to be co-overexpressed in individual insect species via several constitutive overexpression and induction mechanisms, which in turn are co-responsible for high levels of insecticide resistance. Many studies have also demonstrated that the transcriptional overexpression of P450 genes in resistant insects is regulated by trans and/or cis regulatory genes/factors. Taken together, these earlier findings suggest not only that insecticide resistance is conferred via multi-resistance P450 genes, but also that it is mediated through the interaction of regulatory genes/factors and resistance genes. This chapter reviews our current understanding of how the molecular mechanisms of P450 interaction/gene regulation govern the development of insecticide resistance in insects and our progress along the road to a comprehensive characterization of P450 detoxification-mediated insecticide resistance. Copyright © 2015 Elsevier Inc. All rights reserved.

  8. Evolution of insecticide resistance in non-target black flies (Diptera: Simuliidae from Argentina

    Directory of Open Access Journals (Sweden)

    Cristina Mónica Montagna

    2012-06-01

    Full Text Available Black flies, a non-target species of the insecticides used in fruit production, represent a severe medical and veterinary problem. Large increases in the level of resistance to the pyrethroids fenvalerate (more than 355-fold and deltamethrin (162-fold and a small increase in resistance to the organophosphate azinphos methyl (2-fold were observed between 1996-2008 in black fly larvae under insecticide pressure. Eventually, no change or a slight variation in insecticide resistance was followed by a subsequent increase in resistance. The evolution of pesticide resistance in a field population is a complex and stepwise process that is influenced by several factors, the most significant of which is the insecticide selection pressure, such as the dose and frequency of application. The variation in insecticide susceptibility within a black fly population in the productive area may be related to changes in fruit-pest control. The frequency of individuals with esterase activities higher than the maximum value determined in the susceptible population increased consistently over the sampling period. However, the insecticide resistance was not attributed to glutathione S-transferase activity. In conclusion, esterase activity in black flies from the productive area is one mechanism underlying the high levels of resistance to pyrethroids, which have been recently used infrequently. These enzymes may be reselected by currently used pesticides and enhance the resistance to these insecticides.

  9. Evolution of insecticide resistance in non-target black flies (Diptera: Simuliidae) from Argentina.

    Science.gov (United States)

    Montagna, Cristina Mónica; Gauna, Lidia Ester; D'Angelo, Ana Pechen de; Anguiano, Olga Liliana

    2012-06-01

    Black flies, a non-target species of the insecticides used in fruit production, represent a severe medical and veterinary problem. Large increases in the level of resistance to the pyrethroids fenvalerate (more than 355-fold) and deltamethrin (162-fold) and a small increase in resistance to the organophosphate azinphos methyl (2-fold) were observed between 1996-2008 in black fly larvae under insecticide pressure. Eventually, no change or a slight variation in insecticide resistance was followed by a subsequent increase in resistance. The evolution of pesticide resistance in a field population is a complex and stepwise process that is influenced by several factors, the most significant of which is the insecticide selection pressure, such as the dose and frequency of application. The variation in insecticide susceptibility within a black fly population in the productive area may be related to changes in fruit-pest control. The frequency of individuals with esterase activities higher than the maximum value determined in the susceptible population increased consistently over the sampling period. However, the insecticide resistance was not attributed to glutathione S-transferase activity. In conclusion, esterase activity in black flies from the productive area is one mechanism underlying the high levels of resistance to pyrethroids, which have been recently used infrequently. These enzymes may be reselected by currently used pesticides and enhance the resistance to these insecticides.

  10. Decaleside: a new class of natural insecticide targeting tarsal gustatory sites

    Science.gov (United States)

    Rajashekar, Yallappa; Rao, Lingamallu J. M.; Shivanandappa, Thimmappa

    2012-10-01

    Natural sources for novel insecticide molecules hold promise in view of their eco-friendly nature, selectivity, and mammalian safety. Recent progress in understanding the biology of insect olfaction and taste offers new strategies for developing selective pest control agents. We have isolated two natural insecticidal molecules from edible roots of Decalepis hamiltonii named Decalesides I and II, which are novel trisaccharides, highly toxic to household insect pests and stored-product insects. We have experimentally shown that insecticidal activity requires contact with tarsi on the legs but is not toxic orally. The insecticidal activity of molecules is lost by hydrolysis, and various sugars modify toxic response, showing that the insecticidal activity is via gustatory sites on the tarsi. Selective toxicity to insects by virtue of their gustatory site of action and the mammalian safety of the new insecticides is inherent in their chemical structure with 1-4 or 1-1 α linkage that is easily hydrolyzed by digestive enzymes of mammals. Decalesides represent a new chemical class of natural insecticides with a unique mode of action targeting tarsal chemosensory/gustatory system of insects.

  11. Sensitivity of Bemisia tabaci (Hemiptera: Aleyrodidae) to several new insecticides in China: effects of insecticide type and whitefly species, strain, and stage.

    Science.gov (United States)

    Xie, Wen; Liu, Yang; Wang, Shaoli; Wu, Qingjun; Pan, Huipeng; Yang, Xin; Guo, Litao; Zhang, Youjun

    2014-01-01

    Whitefly biotypes B and Q are the two most damaging members of the Bemisia tabaci (Hemiptera: Aleyrodidae) species complex. Control of B. tabaci (and especially of Q) has been impaired by resistance to commonly used insecticides. To find new insecticides for B. tabaci management in China, we investigated the sensitivity of eggs, larvae, and adults of laboratory strains of B and Q (named Lab-B and Lab-Q) and field strains of Q to several insecticides. For eggs, larvae, and adults of B. tabaci and for six insecticides (cyantraniliprole, chlorantraniliprole, pyriproxyfen, buprofezin, acetamiprid, and thiamethoxam), LC50 values were higher for Lab-Q than for Lab-B; avermectin LC50 values, however, were low for adults of both Lab-Q and Lab-B. Based on the laboratory results, insecticides were selected to test against eggs, larvae, and adults of four field strains of B. tabaci Q. Although the field strains differed in their sensitivity to the insecticides, the eggs and larvae of all strains were highly sensitive to cyantraniliprole, and the adults of all strains were highly sensitive to avermectin. The eggs, larvae, and adults of B. tabaci Q were generally more resistant than those of B. tabaci B to the tested insecticides. B. tabaci Q eggs and larvae were sensitive to cyantraniliprole and pyriproxyfen, whereas B. tabaci Q adults were sensitive to avermectin. Field trials should be conducted with cyantraniliprole, pyriproxyfen, and avermectin for control of B. tabaci Q and B in China. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  12. Insecticide resistance to organophosphates in Culex pipiens complex from Lebanon

    Directory of Open Access Journals (Sweden)

    Osta Mike A

    2012-07-01

    Full Text Available Abstract Background Analysis of Culex pipiens mosquitoes collected from a single site in Lebanon in 2005, revealed an alarming frequency of ace-1 alleles conferring resistance to organophosphate insecticides. Following this, in 2006 the majority of municipalities switched to pyrethroids after a long history of organophosphate usage in the country; however, since then no studies have assessed the impact of changing insecticide class on the frequency of resistant ace-1 alleles in C. pipiens. Methods C. pipiens mosquitoes were captured indoors from 25 villages across the country and subjected to established methods for the analysis of gene amplification at the Ester locus and target site mutations in ace-1 gene that confer resistance to organophosphates. Results We conducted the first large-scale screen for resistance to organosphosphates in C. pipiens mosquitoes collected from Lebanon. The frequency of carboxylesterase (Ester and ace-1 alleles conferring resistance to organophosphates were assessed among C. pipiens mosquitoes collected from 25 different villages across the country between December 2008 and December 2009. Established enzymatic assay and PCR-based molecular tests, both diagnostic of the major target site mutations in ace-1 revealed the absence of the F290V mutation among sampled mosquitoes and significant reduction in the frequency of G119S mutation compared to that previously reported for mosquitoes collected from Beirut in 2005. We also identified a new duplicated ace-1 allele, named ace-1D13, exhibiting a resistant phenotype by associating a susceptible and a resistant copy of ace-1 in a mosquito line sampled from Beirut in 2005. Fisher’s exact test on ace-1 frequencies in the new sample sites, showed that some populations exhibited a significant excess of heterozygotes, suggesting that the duplicated allele is still present. Starch gel electrophoresis indicated that resistance at the Ester locus was mainly attributed to the

  13. Contemporary status of insecticide resistance in the major Aedes vectors of arboviruses infecting humans.

    Science.gov (United States)

    Moyes, Catherine L; Vontas, John; Martins, Ademir J; Ng, Lee Ching; Koou, Sin Ying; Dusfour, Isabelle; Raghavendra, Kamaraju; Pinto, João; Corbel, Vincent; David, Jean-Philippe; Weetman, David

    2017-07-01

    Both Aedes aegytpi and Ae. albopictus are major vectors of 5 important arboviruses (namely chikungunya virus, dengue virus, Rift Valley fever virus, yellow fever virus, and Zika virus), making these mosquitoes an important factor in the worldwide burden of infectious disease. Vector control using insecticides coupled with larval source reduction is critical to control the transmission of these viruses to humans but is threatened by the emergence of insecticide resistance. Here, we review the available evidence for the geographical distribution of insecticide resistance in these 2 major vectors worldwide and map the data collated for the 4 main classes of neurotoxic insecticide (carbamates, organochlorines, organophosphates, and pyrethroids). Emerging resistance to all 4 of these insecticide classes has been detected in the Americas, Africa, and Asia. Target-site mutations and increased insecticide detoxification have both been linked to resistance in Ae. aegypti and Ae. albopictus but more work is required to further elucidate metabolic mechanisms and develop robust diagnostic assays. Geographical distributions are provided for the mechanisms that have been shown to be important to date. Estimating insecticide resistance in unsampled locations is hampered by a lack of standardisation in the diagnostic tools used and by a lack of data in a number of regions for both resistance phenotypes and genotypes. The need for increased sampling using standard methods is critical to tackle the issue of emerging insecticide resistance threatening human health. Specifically, diagnostic doses and well-characterised susceptible strains are needed for the full range of insecticides used to control Ae. aegypti and Ae. albopictus to standardise measurement of the resistant phenotype, and calibrated diagnostic assays are needed for the major mechanisms of resistance.

  14. A Comparative Study of the Persistence, Movement and Metabolism of Six Insecticides in Soils and Plants

    International Nuclear Information System (INIS)

    Fuhremann, T.W.; Lichtenstein, E.P.

    1981-01-01

    Full text: Two soil types and oat plants grown in these soils were incubated under identical environmental conditions. The insecticides used in order to increase the water solubility were 14 C-DDT, 14 C-lindane, 14 C-fonofos, 14 C-parathion, 14 C-phorate and 14 C-carbofuran. Total amounts of 14 C-residues recovered from insecticide-treated loam soils plus oats grown in these soils were similar with DDT and oarbofuran. They were also higher than those observed with the other insecticides. While most of the 14 C-DDT residues remained in the soils, most of the 14 C-carbofuran residues were recovered from oat leaves in the form of carbofuran and 3-hydroxycarbofuran. 14 C-residues of all insecticides were more persistent in loam than in sandy soil and sand-grown oats took up more 14 C-insecticide residues than loamgrown oats. The more water-soluble insecticides, 14 C-phorate and Ccarbofuran were more mobile and were metabolized to a greater extent than insecticides of lower water solubilities. Unextractable (bound) 14 C-residues in loam soil ranged from 2.8% to 29.1% of the applied doses of 14 C-DDT and 14 C-parathion, respectively. Bound 14 C-residues were lower in the sandy soil than in the loam soil, however, plant-bound 14 C-residues were higher in oats grown in the sandy soil than in loam grown oats. Insecticide metabolites recovered from soils and plants were identified and quantitated whenever possible. The oxygen analog metabolites of the organophosphorus insecticides were most abundant in the sandy soil and in oats grown therein. Data illustrate the importance of chemical structure, water solubility and soil type in predicting the comparative environmental behaviour of pesticides. (author)

  15. Contemporary status of insecticide resistance in the major Aedes vectors of arboviruses infecting humans

    Science.gov (United States)

    Vontas, John; Martins, Ademir J.; Ng, Lee Ching; Koou, Sin Ying; Dusfour, Isabelle; Raghavendra, Kamaraju; Pinto, João; Corbel, Vincent; David, Jean-Philippe; Weetman, David

    2017-01-01

    Both Aedes aegytpi and Ae. albopictus are major vectors of 5 important arboviruses (namely chikungunya virus, dengue virus, Rift Valley fever virus, yellow fever virus, and Zika virus), making these mosquitoes an important factor in the worldwide burden of infectious disease. Vector control using insecticides coupled with larval source reduction is critical to control the transmission of these viruses to humans but is threatened by the emergence of insecticide resistance. Here, we review the available evidence for the geographical distribution of insecticide resistance in these 2 major vectors worldwide and map the data collated for the 4 main classes of neurotoxic insecticide (carbamates, organochlorines, organophosphates, and pyrethroids). Emerging resistance to all 4 of these insecticide classes has been detected in the Americas, Africa, and Asia. Target-site mutations and increased insecticide detoxification have both been linked to resistance in Ae. aegypti and Ae. albopictus but more work is required to further elucidate metabolic mechanisms and develop robust diagnostic assays. Geographical distributions are provided for the mechanisms that have been shown to be important to date. Estimating insecticide resistance in unsampled locations is hampered by a lack of standardisation in the diagnostic tools used and by a lack of data in a number of regions for both resistance phenotypes and genotypes. The need for increased sampling using standard methods is critical to tackle the issue of emerging insecticide resistance threatening human health. Specifically, diagnostic doses and well-characterised susceptible strains are needed for the full range of insecticides used to control Ae. aegypti and Ae. albopictus to standardise measurement of the resistant phenotype, and calibrated diagnostic assays are needed for the major mechanisms of resistance. PMID:28727779

  16. Contemporary status of insecticide resistance in the major Aedes vectors of arboviruses infecting humans.

    Directory of Open Access Journals (Sweden)

    Catherine L Moyes

    2017-07-01

    Full Text Available Both Aedes aegytpi and Ae. albopictus are major vectors of 5 important arboviruses (namely chikungunya virus, dengue virus, Rift Valley fever virus, yellow fever virus, and Zika virus, making these mosquitoes an important factor in the worldwide burden of infectious disease. Vector control using insecticides coupled with larval source reduction is critical to control the transmission of these viruses to humans but is threatened by the emergence of insecticide resistance. Here, we review the available evidence for the geographical distribution of insecticide resistance in these 2 major vectors worldwide and map the data collated for the 4 main classes of neurotoxic insecticide (carbamates, organochlorines, organophosphates, and pyrethroids. Emerging resistance to all 4 of these insecticide classes has been detected in the Americas, Africa, and Asia. Target-site mutations and increased insecticide detoxification have both been linked to resistance in Ae. aegypti and Ae. albopictus but more work is required to further elucidate metabolic mechanisms and develop robust diagnostic assays. Geographical distributions are provided for the mechanisms that have been shown to be important to date. Estimating insecticide resistance in unsampled locations is hampered by a lack of standardisation in the diagnostic tools used and by a lack of data in a number of regions for both resistance phenotypes and genotypes. The need for increased sampling using standard methods is critical to tackle the issue of emerging insecticide resistance threatening human health. Specifically, diagnostic doses and well-characterised susceptible strains are needed for the full range of insecticides used to control Ae. aegypti and Ae. albopictus to standardise measurement of the resistant phenotype, and calibrated diagnostic assays are needed for the major mechanisms of resistance.

  17. Neonicotinoid Insecticides Alter Induced Defenses and Increase Susceptibility to Spider Mites in Distantly Related Crop Plants

    Science.gov (United States)

    Szczepaniec, Adrianna; Raupp, Michael J.; Parker, Roy D.; Kerns, David; Eubanks, Micky D.

    2013-01-01

    Background Chemical suppression of arthropod herbivores is the most common approach to plant protection. Insecticides, however, can cause unintended, adverse consequences for non-target organisms. Previous studies focused on the effects of pesticides on target and non-target pests, predatory arthropods, and concomitant ecological disruptions. Little research, however, has focused on the direct effects of insecticides on plants. Here we demonstrate that applications of neonicotinoid insecticides, one of the most important insecticide classes worldwide, suppress expression of important plant defense genes, alter levels of phytohormones involved in plant defense, and decrease plant resistance to unsusceptible herbivores, spider mites Tetranychus urticae (Acari: Tetranychidae), in multiple, distantly related crop plants. Methodology/Principal Findings Using cotton (Gossypium hirsutum), corn (Zea mays) and tomato (Solanum lycopersicum) plants, we show that transcription of phenylalanine amonia lyase, coenzyme A ligase, trypsin protease inhibitor and chitinase are suppressed and concentrations of the phytohormone OPDA and salicylic acid were altered by neonicotinoid insecticides. Consequently, the population growth of spider mites increased from 30% to over 100% on neonicotinoid-treated plants in the greenhouse and by nearly 200% in the field experiment. Conclusions/Significance Our findings are important because applications of neonicotinoid insecticides have been associated with outbreaks of spider mites in several unrelated plant species. More importantly, this is the first study to document insecticide-mediated disruption of plant defenses and link it to increased population growth of a non-target herbivore. This study adds to growing evidence that bioactive agrochemicals can have unanticipated ecological effects and suggests that the direct effects of insecticides on plant defenses should be considered when the ecological costs of insecticides are evaluated. PMID

  18. Modes of Action, Resistance and Toxicity of Insecticides Targeting Nicotinic Acetylcholine Receptors.

    Science.gov (United States)

    Ihara, Makoto; Buckingham, Steven D; Matsuda, Kazuhiko; Sattelle, David B

    2017-01-01

    Nicotinic acetylcholine receptors (nAChRs) of insects play a key role in fast excitatory neurotransmission. Several classes of insecticides target insect nAChRs, which are composed of subunit members of a family of multiple subunit encoding genes. Alternative splicing and RNA A-to-I editing can add further to receptor diversity. Native and recombinant receptors have been explored as sites of insecticide action using radioligands, electrophysiology and site-directed mutagenesis. We have reviewed the properties of native and recombinant insect nAChRs, the challenges of functional recombinant insect nAChR expression, nAChR interactions with ligands acting at orthosteric and allosteric sites and in particular their interactions with insecticides. Actions on insect nAChRs of cartap, neonicotinoids, spinosyns, sulfoxamines, butenolides and mesoionic insecticides are reviewed and current knowledge of their modes of action are addressed. Mutations that add to our understanding of insecticide action and those leading to resistance are discussed. Co-crystallisation of neonicotinoids with the acetylcholine binding protein (AChBP), a surrogate for the nAChR ligand binding domain, has proved instructive. Toxicity issues relating to insecticides targeting nAChRs are also considered. An overview of insecticide classes targeting insect nAChRs has enhanced our understanding of these important receptors and their insecticide binding sites. However, the subunit composition of native nAChRs remains poorly understood and functional expression still presents difficulties. These topics together with improved understanding of the precise sites of insecticide actions on insect nAChRs will be the subject of future research. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  19. Household use of insecticide consumer products in a dengue endemic area in México

    Science.gov (United States)

    Loroño-Pino, María Alba; Chan-Dzul, Yamili N.; Zapata-Gil, Rocio; Carrillo-Solís, Claudia; Uitz-Mena, Ana; García-Rejón, Julián E.; Keefe, Thomas J.; Beaty, Barry J.; Eisen, Lars

    2014-01-01

    Objectives To evaluate household use of insecticide consumer products to kill mosquitoes and other insect pests, as well as the expenditures for using these products, in a dengue endemic area in México. Methods A questionnaire was administered to 441 households in Mérida City or other communities in Yucatán State to assess household use of insecticide consumer products. Results Most (86.6%) households took action to kill insect pests with consumer products. Among those households, the most commonly used product types were insecticide aerosol spray cans (73.6%), electric plug-in insecticide emitters (37.4%), and mosquito coils (28.3%). Mosquitoes were targeted by 89.7% of households using insecticide aerosol spray cans and >99% of households using electric plug-in insecticide emitters or mosquito coils. During the part of the year when a given product type was used, the frequency of use was daily or every 2 days in most of the households for insecticide aerosol spray cans (61.4%), electric plug-in insecticide emitters (76.2%), and mosquito coils (82.1%). For all products used to kill insect pests, the median annual estimated expenditure per household that took action was 408 Mexican pesos ($MXN), which corresponded to ∼31 $U.S. These numbers are suggestive of an annual market in excess of 75 million $MXN (>5.7 million $U.S.) for Mérida City alone. Conclusion Mosquitoes threaten human health and are major nuisances in homes in the study area in México. Households were found to have taken vigorous action to kill mosquitoes and other insect pests and spent substantial amounts of money on insecticide consumer products. PMID:25040259

  20. Household use of insecticide consumer products in a dengue-endemic area in México.

    Science.gov (United States)

    Loroño-Pino, María Alba; Chan-Dzul, Yamili N; Zapata-Gil, Rocio; Carrillo-Solís, Claudia; Uitz-Mena, Ana; García-Rejón, Julián E; Keefe, Thomas J; Beaty, Barry J; Eisen, Lars

    2014-10-01

    To evaluate the household use of insecticide consumer products to kill mosquitoes and other insect pests, as well as the expenditures for using these products, in a dengue-endemic area of México. A questionnaire was administered to 441 households in Mérida City and other communities in Yucatán to assess household use of insecticide consumer products. A total of 86.6% of surveyed households took action to kill insect pests with consumer products. The most commonly used product types were insecticide aerosol spray cans (73.6%), electric plug-in insecticide emitters (37.4%) and mosquito coils (28.3%). Mosquitoes were targeted by 89.7% of households using insecticide aerosol spray cans and >99% of households using electric plug-in insecticide emitters or mosquito coils. Products were used daily or every 2 days in most of the households for insecticide aerosol spray cans (61.4%), electric plug-in insecticide emitters (76.2%) and mosquito coils (82.1%). For all products used to kill insect pests, the median annual estimated expenditure per household that took action was 408 Mexican pesos ($MXN), which corresponded to approximately 31 $US. These numbers are suggestive of an annual market in excess of 75 million $MXN (>5.7 million $US) for Mérida City alone. Mosquitoes threaten human health and are major nuisances in homes in the study area in México. Households were found to have taken vigorous action to kill mosquitoes and other insect pests and spent substantial amounts of money on insecticide consumer products. © 2014 John Wiley & Sons Ltd.

  1. Environmental risks and challenges associated with neonicotinoid insecticides

    Science.gov (United States)

    Hladik, Michelle L.; Main, Anson; Goulson, Dave

    2018-01-01

    Neonicotinoid use has increased rapidly in recent years, with a global shift towards insecticide applications as seed coatings rather than aerial spraying. While the use of seed coatings can lessen the amount of overspray and drift, the near universal and prophylactic use of neonicotinoid seed coatings on major agricultural crops has led to widespread detections in the environment (pollen, soil, water, honey). Pollinators and aquatic insects appear to be especially susceptible to the effects of neonicotinoids with current research suggesting that chronic sub-lethal effects are more prevalent than acute toxicity. Meanwhile, evidence of clear and consistent yield benefits from the use of neonicotinoids remains elusive for most crops. Future decisions on neonicotinoid use will benefit from weighing crop yield benefits versus environmental impacts to non-target organisms and considering whether there are more environmentally benign alternatives.

  2. Organophosphate insecticide poisoning of Canada geese in the Texas panhandle

    Science.gov (United States)

    White, D.H.; Mitchell, C.A.; Wynn, L.D.; Flickinger, Edward L.; Kolbe, E.J.

    1982-01-01

    Sixteen hundred waterfowl, mostly Canada Geese, died near Etter, Texas, in late January 1981 from anticholinesterase poisoning. Winter wheat in the area of the die-off had been treated with organophosphate insecticides to control greenbugs. Cholinesterase (ChE) levels in brains of a sample of geese found dead were 75% below normal, enough to account for death (Ludke et al. 1975). The gastrointestinal (G I) tracts of geese found dead were packed with winter wheat; gas chromatography techniques identified parathion and methyl parathion in the GI tract contents. Residues of both chemicals were confirmed by mass spectrometry. We recommend that less toxic materials, such as malathion, be used on grain crops when waterfowl are in the vicinity of treatment.

  3. Impact of repeated insecticide application on soil microbial activity

    International Nuclear Information System (INIS)

    Xu Bujin; Zhang Yongxi; Chen Meici; Zhu Nanwen; Ming Hong

    2001-01-01

    The effects of repeated insecticide application on soil microbial activity were studied both in a cotton field and in the laboratory. The results of experiment show that there are some effects on soil microbial activities, such as the population of soil microorganisms, soil respiration, dehydrogenase activity and nitrogen fixation. The degree of effects depends on the chemical dosage. Within the range of 0.5-10.0 μg/g air-dry-soil, the higher the concentration, the stronger effect. In this experiment, the effect disappeared within 4, 8 or 16 days after treatment, depending on the dose applied. In field conditions, the situation is more complex and the data of field experiment show greater fluctuation. (author)

  4. Neural network-based QSAR and insecticide discovery: spinetoram

    Science.gov (United States)

    Sparks, Thomas C.; Crouse, Gary D.; Dripps, James E.; Anzeveno, Peter; Martynow, Jacek; DeAmicis, Carl V.; Gifford, James

    2008-06-01

    Improvements in the efficacy and spectrum of the spinosyns, novel fermentation derived insecticide, has long been a goal within Dow AgroSciences. As large and complex fermentation products identifying specific modifications to the spinosyns likely to result in improved activity was a difficult process, since most modifications decreased the activity. A variety of approaches were investigated to identify new synthetic directions for the spinosyn chemistry including several explorations of the quantitative structure activity relationships (QSAR) of spinosyns, which initially were unsuccessful. However, application of artificial neural networks (ANN) to the spinosyn QSAR problem identified new directions for improved activity in the chemistry, which subsequent synthesis and testing confirmed. The ANN-based analogs coupled with other information on substitution effects resulting from spinosyn structure activity relationships lead to the discovery of spinetoram (XDE-175). Launched in late 2007, spinetoram provides both improved efficacy and an expanded spectrum while maintaining the exceptional environmental and toxicological profile already established for the spinosyn chemistry.

  5. Blood pyrrole-protein adducts as a diagnostic and prognostic index in pyrrolizidine alkaloid-hepatic sinusoidal obstruction syndrome

    Directory of Open Access Journals (Sweden)

    Gao H

    2015-08-01

    Full Text Available Hong Gao,1,* Jianqing Q Ruan,2,* Jie Chen,1 Na Li,2 Changqiang Q Ke,3 Yang Ye,3–5 Ge Lin,2,4,5 Jiyao Y Wang1,61Department of Gastroenterology, Zhongshan Hospital, Fudan University, Shanghai, People’s Republic of China; 2School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong; 3Shanghai Institute of Materia Medica, Shanghai, People’s Republic of China; 4Joint Research Laboratory for Promoting Globalization of Traditional Chinese Medicines, Shanghai Institute of Materia Medica, 5Chinese University of Hong Kong, Hong Kong; 6Center of Evidence-Based Medicine Fudan University, Shanghai, People’s Republic of China*These authors contributed equally to this work and share first authorship Background: The diagnosis of hepatic sinusoidal obstruction syndrome (HSOS induced by pyrrolizidine alkaloids is mainly based on clinical investigation. There is currently no prognostic index. This study evaluated the quantitative measurement of blood pyrrole-protein adducts (PPAs as a diagnostic and prognostic index for pyrrolizidine alkaloid-induced HSOS.Methods: Suspected drug-induced liver injury patients were prospectively recruited. Blood PPAs were quantitatively measured using ultra-performance liquid chromatography-tandem mass spectrometry. Patients’ age, sex, biochemistry test results, and a detailed drug history were recorded. The patients were divided into two groups, ie, those with HSOS induced by pyrrolizidine alkaloid-containing drugs and those with liver injury induced by drugs without pyrrolizidine alkaloids. The relationship between herb administration, clinical outcomes, blood sampling time, and blood PPA concentration in pyrrolizidine alkaloid-associated HSOS patients was analyzed using multiple linear regression analysis.Results: Forty patients met the entry criteria, among whom 23 had pyrrolizidine alkaloid-associated HSOS and 17 had liver injury caused by drugs without pyrrolizidine alkaloids. Among the 23

  6. Neonicotinoid insecticides induce salicylate-associated plant defense responses

    Science.gov (United States)

    Ford, Kevin A.; Casida, John E.; Chandran, Divya; Gulevich, Alexander G.; Okrent, Rachel A.; Durkin, Kathleen A.; Sarpong, Richmond; Bunnelle, Eric M.; Wildermuth, Mary C.

    2010-01-01

    Neonicotinoid insecticides control crop pests based on their action as agonists at the insect nicotinic acetylcholine receptor, which accepts chloropyridinyl- and chlorothiazolyl-analogs almost equally well. In some cases, these compounds have also been reported to enhance plant vigor and (a)biotic stress tolerance, independent of their insecticidal function. However, this mode of action has not been defined. Using Arabidopsis thaliana, we show that the neonicotinoid compounds, imidacloprid (IMI) and clothianidin (CLO), via their 6-chloropyridinyl-3-carboxylic acid and 2-chlorothiazolyl-5-carboxylic acid metabolites, respectively, induce salicylic acid (SA)-associated plant responses. SA is a phytohormone best known for its role in plant defense against pathogens and as an inducer of systemic acquired resistance; however, it can also modulate abiotic stress responses. These neonicotinoids effect a similar global transcriptional response to that of SA, including genes involved in (a)biotic stress response. Furthermore, similar to SA, IMI and CLO induce systemic acquired resistance, resulting in reduced growth of a powdery mildew pathogen. The action of CLO induces the endogenous synthesis of SA via the SA biosynthetic enzyme ICS1, with ICS1 required for CLO-induced accumulation of SA, expression of the SA marker PR1, and fully enhanced resistance to powdery mildew. In contrast, the action of IMI does not induce endogenous synthesis of SA. Instead, IMI is further bioactivated to 6-chloro-2-hydroxypyridinyl-3-carboxylic acid, which is shown here to be a potent inducer of PR1 and inhibitor of SA-sensitive enzymes. Thus, via different mechanisms, these chloropyridinyl- and chlorothiazolyl-neonicotinoids induce SA responses associated with enhanced stress tolerance. PMID:20876120

  7. Cation Recognition: Novel Potentiometric PVC-Membrane Sensor based on Meso-octamethylcalix[4]pyrrole for the Determination of Trace Amounts of Titanium (III) Ions

    International Nuclear Information System (INIS)

    Saeid Ahmadzadeh; Anuar Kassim Majid Rezayi

    2011-01-01

    The present work deals with developing a novel high selective membrane electrode based on meso-octamethylcalix[4]pyrrole for accurate determination of trace amount of titanium (III) ions in real sample solutions. The amounts of ionophore (4 mg), PVC (33 mg), dioctyl phthalate (DOP) as plasticizer (62.8 mg) and sodium tetrakis [3,5-bis (trifluoromethyl) phenyl] borate (NaTFPB) as an ionic additive (0.2 mg) were optimized in the preparation of the membrane. The electrode exhibited a linear response with a near Nernstian slope of 29.49±0.16 (mV per decade of activity) over the pH range from 1 to 3 with a satisfactory concentration range of 1.0 x 10 -6 to 1.0 x x10 -2 M. The developed sensor exhibited good reproducibility over a period of about 3 months with a fast response time of 15 seconds. (author)

  8. Emission and absorption of light in poly pyrrole synthesized by plasma; Emision y absorcion de luz en polipirrol sintetizado por plasma

    Energy Technology Data Exchange (ETDEWEB)

    Enriquez, M.A.; Colin, E.; Olayo, M.G.; Cruz, G.J.; Ordonez, E. [ININ, A.P. 18-1027, 11801 Mexico D.F. (Mexico); Benavides, R. [Departamento de Procesos de Transformacion, CIQA, Blvd. Enrique Reyna 140, Saltillo, Coahuila (Mexico); Morales, J.; Olayo, R. [UAM-I, Apdo. Postal 55-534, Iztapalapa, D.F. (Mexico)]. e-mail: gcc@nuclear.inin.mx

    2007-07-01

    The poly pyrrole structure (PPy) consists of heterocyclic rings with conjugation that it depends on the intensity of the electric field applied during the synthesis, and its luminescence is related with the {pi}-{pi}{sup *} transitions of that conjugation. To irradiate with light of different wavelengths, the results indicate that the polymer absorbs in the interval from 290 to 700 nm and it emits between 450 and 470 nm. The basal conductivity of the polymers, without electromagnetic excitation, it was measured in 10{sup -15} S/cm, however, to interact with visible light it is increased approximately 10 times and when excite with UV light it is increased up to 3 magnitude orders. (Author)

  9. Monoclonal Antibody Analysis and Insecticidal Spectrum of Three Types of Lepidopteran-Specific Insecticidal Crystal Proteins of Bacillus thuringiensis

    Science.gov (United States)

    Höfte, Herman; Van Rie, Jeroen; Jansens, Stefan; Van Houtven, Annemie; Vanderbruggen, Hilde; Vaeck, Mark

    1988-01-01

    We have investigated the protein composition and the insecticidal spectrum of crystals of 29 Bacillus thuringiensis strains active against lepidopteran larvae. All crystals contained proteins of 130 to 140 kilodaltons (kDa) which could be grouped into three types by the molecular weight of the protoxin and the trypsin-activated core fragment. Proteins of the three types showed a characteristic insecticidal spectrum when tested against five lepidopteran species. Type A crystal proteins were protoxins of 130 or 133 kDa, which were processed into 60-kDa toxins by trypsin. Several genes encoding crystal proteins of this type have been cloned and sequenced earlier. They are highly conserved in the N-terminal half of the toxic fragment and were previously classified in three subtypes (the 4.5-, 5.3-, and 6.6-kilobase subtypes) based on the restriction map of their genes. The present study shows that different proteins of these three subtypes were equally toxic against Manduca sexta and Pieris brassicae and had no detectable activity against Spodoptera littoralis. However, the 4.5-, 5.3-, and 6.6-kilobase subtypes differed in their toxicity against Heliothis virescens and Mamestra brassicae. Type B crystal proteins consisted of 140-kDa protoxins with a 55-kDa tryptic core fragment. These were only active against one of the five insect species tested (P. brassicae). The protoxin and the trypsin-activated toxin of type C were 135- and 63-kDa proteins, respectively. Proteins of this type were associated with high toxicity against S. littoralis and M. brassicae. A panel of 35 monoclonal antibodies was used to compare the structural characteristics of crystal proteins of the three different types and subtypes. Each type of protein could be associated with a typical epitope structure, indicating an unambiguous correlation between antigenic structure and insect specificity. Images PMID:16347711

  10. Digestive enzyme as benchmark for insecticide resistance development in Culex pipiens larvae to chemical and bacteriologic insecticides.

    Science.gov (United States)

    Kamel, Nashwa H; Bahgat, Iman M; El Kady, Gamal A

    2013-04-01

    This work monitored changes in some digestive enzymes (trypsin and aminopeptidase) associated with the building up of resistance in Cx. pipiens larvae to two chemical insecticides (methomyl and/or malathion) and one biological insecticide (Bacillus thuringiensis-H14 or B.t H 14). The LC50 value of methomyl for both field- and the 12th generation (F12) of the selected strain was 1.789 ppm and 8.925 ppm respectively. The LC50 value of malathion for both field and the F12 of the selected strain was 0.082 ppm and 0.156 ppm respectively, and those of B.t H14 of field strain and the F12 was 2.550ppm & 2.395ppm respectively. The specific activity of trypsin enzyme in control susceptible colony was 20.806 +/- 0.452micromol/min/mg protein; but at F4 and F8 for malathion and methomyl treated larvae were 10.810 +/- 0.860 & 15.616+/-0.408 micromol/min/mg protein, respectively. Trypsin activity of F12 in treated larvae with B.t.H14 was 2.097 +/- 0.587 microiol/min/mg protein. Aminopeptidase specific activity for susceptible control larvae was 173.05 +/- 1.3111 micromol/min/mg protein. This activity decreased to 145.15 +/- 4.12, 152.497 +/- 6.775 & 102.04 +/- 3.58a micromol/min/mg protein after larval (F 12) treatment with methomyl, malathion and B.t H 14 respectively.

  11. Determination of insecticidal activity of Heliopsis longipes A. Gray Blake, an endemic plant of Guanajuato state

    Directory of Open Access Journals (Sweden)

    Alejandro Hernández Morales

    2012-09-01

    Full Text Available Mosquitoes are involved in transmission of infectious diseases like malaria which affect human health, causing economic losses due to expensive treatments and job incapacity of patients. Strategies to minimize transmission of this disease are the employ of chemical insecticides that are excellent methods to reduce insect populations; however it causes deleterious effects on human health and environmental damage. Therefore is necessary to explore harmless alternatives, such as plant extracts which are potential source of natural insecticides. In this work we evaluated insecticidal properties of Heliopsis longipes A. Gray Blake against third instar larvae of Anopheles albimanus, malaria vector. Results showed that H.longipes A. Gray Blake has insecticide properties to control insect involved in malaria transmission.

  12. Application of nanotechnology for the encapsulation of botanical insecticides for sustainable agriculture: prospects and promises.

    Science.gov (United States)

    de Oliveira, Jhones Luiz; Campos, Estefânia Vangelie Ramos; Bakshi, Mansi; Abhilash, P C; Fraceto, Leonardo Fernandes

    2014-12-01

    This review article discusses the use of nanotechnology in combination with botanical insecticides in order to develop systems for pest control in agriculture. The main types of botanical insecticides are described, together with different carrier systems and their potential uses. The botanical insecticides include those based on active principles isolated from plant extracts, as well as essential oils derived from certain plants. The advantages offered by the systems are highlighted, together with the main technological challenges that must be resolved prior to future implementation of the systems for agricultural pest control. The use of botanical insecticides associated with nanotechnology offers considerable potential for increasing agricultural productivity, while at the same time reducing impacts on the environment and human health.

  13. Year-round presence of neonicotinoid insecticides in tributaries to the Great Lakes, USA

    Science.gov (United States)

    To better understand the transport of neonicotinoid insecticides to a sensitive freshwater ecosystem, monthly samples (October 2015-September 2016) were collected from 10 major tributaries to the Great Lakes, USA. For the monthly tributary samples, neonicotinoids were detected in...

  14. Daphnid life cycle responses to the insecticide chlorantraniliprole and its transformation products

    NARCIS (Netherlands)

    Lavtižar, V.; Helmus, R.; Kools, S.A.E.; Dolenc, D; van Gestel, C.A.M.; Trebše, P.; Waaijers, S.L.; Kraak, M.H.S.

    2015-01-01

    Chlorantraniliprole (CAP) is a newly developed, widely applied insecticide. In the aquatic environment, several transformation products are formed under natural conditions, one by dehydration and others by photoinduced degradation. Data on aquatic ecotoxicity of CAP can mainly be found in

  15. Control of sugar beet pests at early season by seed treatment with insecticides

    Directory of Open Access Journals (Sweden)

    Kereši Tatjana

    2006-01-01

    Full Text Available In the period 2001-2004, experiments were conducted in the region of Bačka (northern Serbia to assess the efficiency of insecticide treatment of sugar beet seeds in controlling soil pests (larvae of Elateridae family and reducing the damage caused by beet weevil (Bothynoderes punctiventris G e r m and flea beetle (Chaetocnema tibialis I l l i g. Several insecticides mostly systemic ones (carbofuran, thiamethoxam, fipronil, imidacloprid and clothianidin, and their combinations with pyrethroids in different doses were tested in field conditions. Stand density, percentages of plants damaged by B. punctiventris and C. tibialis, injury level and weight of juvenile plants served as parameters for evaluation of insecticide efficiency. Most of the insecticides applied to seeds provided a significantly better stand density compared with the untreated control. Because of their systemic action, imidacloprid, thiamethoxam and their mixtures with pyrethroids provided very good protection of juvenile plants from C. tibialis and in some cases from B. punctiventris.

  16. Perceived Threat of Malaria and the Use of Insecticide Treated Bed ...

    African Journals Online (AJOL)

    2013-12-17

    Dec 17, 2013 ... Keywords: malaria; children; insecticide treated nets; health belief model; .... including malaria, were usually handled by the only designated nurse. .... The familiar saying that “prevention is better and cheaper than cure” may ...

  17. The effect of insecticide-treated bed net on malarial parasitaemia ...

    African Journals Online (AJOL)

    AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search ... nets sold by a social marketing project were used as the intervention group. ... Keywords: Insecticide-treated bed net, Effectiveness, Malaria control, South-South Nigeria.

  18. Outcome of Patients with Cholinergic Insecticide Poisoning Treated with Gastric Lavage: A Prospective Observational Cohort Study

    Directory of Open Access Journals (Sweden)

    Mekkattukunnel Andrews

    2014-12-01

    Conclusion: Number or timing of GL does not show any association with mortality while multiple GL had protective effect against development of late RF and IMS. Hence, GL might be beneficial in cholinergic insecticide poisoning.

  19. Design, Synthesis, and Insecticidal Activity of Some Novel Diacylhydrazine and Acylhydrazone Derivatives

    Directory of Open Access Journals (Sweden)

    Jialong Sun

    2015-03-01

    Full Text Available In this study a series of diacylhydrazine and acylhydrazone derivatives were designed and synthesized according to the method of active group combination and the principles of aromatic group bioisosterism. The structures of the novel derivatives were determined on the basis on 1H-NMR, IR and ESI-MS spectral data. All of the compounds were evaluated for their in vivo insecticidal activity against the third instar larvae of Spodoptera exigua Hiibner, Helicoverpa armigera Hubner, Plutella xyllostella Linnaeus and Pieris rapae Linne, respectively, at a concentration of 10 mg/L. The results showed that all of the derivatives displayed high insecticidal activity. Most of the compounds presented higher insecticidal activity against S. exigua than the reference compounds tebufenozide, metaflumizone and tolfenpyrad, and approximately identical insecticidal activity against H. armigera, P. xyllostella and P. rapae as the references metaflumizone and tolfenpyrad.

  20. Interaction of insecticide and media moisture on ambrosia beetle (Coleoptera: Curculionidae) attacks on ornamental trees

    Science.gov (United States)

    Exotic ambrosia beetles, particularly Xylosandrus crassiusculus (Motschulsky) and Xylosandrus germanus (Blandford), are among the most economically damaging pests of ornamental trees in nurseries. Growers have had few tactics besides insecticide applications to reduce ambrosia beetle attacks but rec...