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Behavioral Outcomes and Molecular Marker Modulation during Learning and Memory Formation following Developmental Exposure to Organophoshorus InsecticidesJohnson, Frank Orlando 15 December 2007 (has links)
Effects of developmental exposure to chlorpyrifos (CPS) or methyl parathion (MPS) on visuospatial, adaptive fear response, and passive avoidance memory and the signaling mechanisms responsible for these neurocognitive changes were investigated. Using an incremental low dose regimen, rat pups were orally gavaged daily with either corn oil (vehicle), CPS, or MPS from postnatal day 1 (PND1) -PND21. Cholinesterase activity was significantly inhibited with the highest dosages of CPS and MPS for up to 19 days after the last dosages. OP exposure impaired working and reference memory in males whereas in the females, enhancement occurred following CPS exposure. In addition, the adaptive fear response and passive avoidance retention memory was impaired in males whereas differential changes occurred in females. Accordingly, the behavioral deficits observed in males were persistent whereas the enhancement in females was transient. Males were more sensitive to OPs than females in that the medium and high dosages of CPS and MPS produced greater effects in females whereas all dosages of both compounds produced effects in males. Training in the radial arm maze significantly increased protein kinase C gamma (PKC ) expression and activity in the hippocampal membrane fraction of control rats whereas exposure to OPs exhibited a significant decrease in PKC and PKC immunoreactivity in both untrained and trained rats. However, MPS exposed females exhibited a significant increase in PKC expression in the cytosolic fraction but this was not related to improved memory. Reduction of membrane PKC expression and activity and cytosolic PKC expression and activity seemed to be related to visuospatial learning and memory deficits in exposed males but not exposed females. Brain-derived neurotrophic factor (BDNF) gene expression in the hippocampus was significantly increased (60%) in trained control males as compared to untrained control males. In contrast, trained and untrained females exhibited similar levels of BDNF gene expression. However, exposure of both sexes to either CPS or MPS significantly reduced the expression of BDNF in trained rats. In summary, these data indicate that OP exposure induced gender-specific changes in working memory formation and altered PKC isozyme levels/activity and BDNF expression.
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Suivi d’abeilles domestiques et de pollinisateurs indigènes lors des semis de cultures traitées aux néonicotinoïdesSamson-Robert, Olivier 23 April 2018 (has links)
Les insecticides néonicotinoïdes, qui sont omniprésents en agriculture, sont un des principaux facteurs impliqués dans le déclin des populations d’abeilles domestiques et d’autres pollinisateurs sauvages. Dans cette étude, nous avons évalué les impacts des traitements de semences néonicotinoïdes sur le niveau de mortalité des abeilles domestiques, l’intoxication du bourdon fébrile (par le suivi d’un biomarqueur, acétylcholinestérase ou AChE) ainsi que sur la contamination de l’eau. Les résultats démontrent qu’à proximité des semis de maïs traités à l’insecticide le niveau de mortalité des colonies d’abeilles domestiques est quadruplé et le niveau d’AChE des bourdons est également plus élevé. Le projet a également permis de confirmer que les flaques d’eau à la surface des champs sont une nouvelle voie d’intoxication potentielle pour les abeilles. Ces résultats démontrent les nombreux impacts de l’utilisation massive des traitements de semences néonicotinoïdes et met en évidence le rôle essentiel qu'ils jouent dans l’actuel déclin des pollinisateurs. / Neonicotinoid insecticides, which are ubiquitous in agriculture, are one of the main factors involved in the recent decline of honey bees’ and native pollinators’ populations. In this study, we evaluated the impact of neonicotinoid seed treatments on honey bee mortality levels, bumble bees intoxication (through monitoring of acetylcholinesterase (AChE) as a biomarker) and water contamination. The results show that honey bee mortality level is quadrupled and that AChE levels of bumble bees are higher when living and foraging in a pesticide-treated corn-dominated environment. The project also confirmed that puddles of water at the surface of corn fields are a new potential route of intoxication for bees. These results demonstrate the harmful impact of the widespread use of neonicotinoid seed treatments and highlight the key role they play in the current pollinators’ decline.
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DDE METABOLISM BY THE ISOLATED PERFUSED BOVINE LIVER.Arnold, Jean E. D. January 1983 (has links)
No description available.
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Methoprene as a protectant against five species of stored-product insects in wheatZeledon, Manuel E. January 1984 (has links)
Call number: LD2668 .T4 1984 Z44 / Master of Science
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Effects of biogenic amines and formamidine insecticides on the central production of flight by Manduca sextaClaassen, Dale E. January 1985 (has links)
Call number: LD2668 .T4 1985 C52 / Master of Science
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Résistance Métabolique des Larves de Moustiques aux Insecticides : Conséquences EnvironnementalesBoyer, Sébastien 29 September 2006 (has links) (PDF)
Dans un contexte de lutte intégrée contre les moustiques, l'Entente Interdépartementale pour la Démoustication (E.I.D. Ain, Isère, Rhône, Savoie Rhône-Alpes s'est tournée vers une lutte totalement biologique (Bti) pour lutter contre les moustiques. Mon sujet de thèse s'inscrit dans la suite d'une collaboration scientifique constante depuis 40 ans entre l'E.I.D. et le laboratoire de recherche dans lequel j'ai effectué ma thèse. Cet organisme de gestion utilise le Bti depuis 20 ans. Et bien qu'à ce jour, aucune population de moustique ne soit apparue résistante au Bti, ce gestionnaire s'interroge sur la possibilité d'apparition de populations résistantes aux traitements insecticides. Des travaux antérieurs ont laissé supposer qu'il existait une différence de sensibilité des larves de moustiques aux insecticides en fonction de leur gîte d'origine, les larves originaires de gîtes herbacées étant moins tolérantes que celles provenant des gîtes arborescents. Il nous a semblé nécessaire de comprendre et ainsi de s'intéresser aux différents mécanismes de résistance des larves de moustiques pour permettre, demain, une lutte plus efficace contre cet insecte. Et nous nous intéresserons à la résistance à divers xénobiotiques alimentaires : du téméphos (insecticide organophosphoré) au Bacillus thuringiensis var. israelensis (Bti - bactério-insecticide) en passant par de la litière naturelle issue de la décomposition de feuilles dans les gîtes à moustiques se révélant toxique pour les larves. L'intérêt de cette thèse est double. D'un point de vue fondamental, la connaissance et la compréhension de la résistance (des enzymes impliquées aux facteurs environnementaux en passant par les gènes mis en jeu) stimulent mes recherches. Et d'un point de vue appliqué, il est nécessaire de mettre au point, enfin, un système de lutte efficace non polluant, qui passe par la compréhension globale des résistances. La démarche expérimentale utilisée dans ce travail est d'identifier les dysfonctionnements environnementaux sur le terrain, les analyser au laboratoire sur des espèces modèles (ici Aedes aegypti) les mécanismes à l'origine de ces perturbations, puis revenir sur le terrain pour confronter les résultats de laboratoire avec ceux obtenus in natura (ici Ochlerotatus cataphylla, Aedes rusticus). Ainsi cette étude va porter à la fois sur des espèces de terrain (Aedes rusticus, Ochlerotatus cataphylla, Culex pipiens ...) que sur des espèces de laboratoires (Aedes aegypti, Aedes albopictus ...). Pour comprendre les mécanismes de résistance mis en jeu par ce nuisant, nous avons travaillés à plusieurs niveaux d'études avec des études écotoxicologiques réalisées grâce à des études de terrain en collaboration avec l'E.I.D. (Entente Interdépartementale pour la Démoustication), des études biochimiques nous permettant de caractériser les enzymes de résistance mises en jeu, et des études génétiques et moléculaires pour approfondir ces mécanismes, en espérant trouver les gènes impliqués.
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Entomopathogenic Nematodes: Their Interactions with Plant Pathogens and Insecticides in the SoilNavarro, Patricia D. January 2012 (has links)
Entomopathogenic nematodes (EPNs) in the families Heterorhabditidae and Steinernematidae, and their bacterial symbionts, have been studied intensively because of their role as natural mortality factor for soil-dwelling arthropods, and their potential as biological control agents for belowground insect pests. Moreover, EPN are recognized as key players in regulating soil food webs and triggering trophic cascades. However, most studies of interactions with EPN have been conducted under laboratory setting and simplified conditions, without consider the dynamic of the EPN and their interactions with other soil components in a wider context. In this respect, knowledge of the effect that other soil organisms or human induced factor may have on EPN dynamic and life cycle in the soil may contribute to improve tactics for their implementation and success as natural regulators of herbivores. The present investigation focused on the interactions of EPN with a selection of insecticides, and biotic (saprobic fungus and plant parasitic nematodes) elements that may be present in the soil, and may potentially interact with EPN. Specifically, I investigated how these factors may affect the life cycle (host search behavior, virulence and reproduction) of EPN. Appendix A shows the effect that a group of selected synthetic and biological insecticides have on EPN virulence and reproduction. The results obtained from this study revealed that most combinations of EPN and insecticides under study increased the mortality of the insect host. However, it was also found that some of these combinations reduced the nematode progeny production and emergence of IJs from the insect cadaver. In contrast in Appendix B, when examining the effect of the saprobic fungus Fusarium oxysporum in the life cycle of the EPN Heterorhabditis sonorensis, it was found that this fungus negatively affected the virulence and reproduction of the EPN in the insect host. In the third study of this dissertation (Appendix C) the interactions studied considered the effect of two EPN on an organism of a different trophic guild, the plant parasitic nematode Tylenchulus semipenetrans. This plant parasitic nematode causes serious diseases in citrus plants by infecting their roots and defoliating their branches. Previous studies have shown that some EPN species may negatively affect the life cycle of plant parasitic nematodes by reducing the damage produced by this plant parasite. Results from this study confirm the antagonistic effect between the selected EPN and the citrus nematode. Specifically, it was found that the presence in the soil of both EPN reduced the survival of infective juveniles of the citrus nematode and their penetration to the root. Moreover, the presence of EPN had an antagonistic effect in the production of eggs of T. semipenetrans females.
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THE POSSIBLE TRANSLOCATION OR SUBLIMATION OF DDE IN ALFALFA.Lingafeldt, Nancy Elizabeth. January 1982 (has links)
No description available.
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EVALUATION OF GOSSYPLURE TRAP NUMBER AND FIELD PLACEMENT FOR MONITORING MALE PINK BOLLWORM, PECTINOPHORA GOSSYPIELLA (SAUNDERS) IN COTTON.Chesser, Charles Curtis. January 1984 (has links)
No description available.
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Synthesis and Insecticidal Activity of Gem-Cyano PyrethroidsWilkerson, Michael G. 08 1900 (has links)
The synthesis and insecticidal activity of a series of 2,2-dicyano cyclopropane carboxylic acids, (3-phenoxyphenyl)- methyl esters were investigated. Synthesis of the compounds was accomplished by reaction of a dimethyl sulfonium carbethoxy ylide with propanedinitrile alkylidene compounds. Final products were formed in one step by use of the (3-phenoxyphenyl)-methyl ester of the ylide. Insecticidal activity was determined at 500 ppm application with Permethrin as the standard against houseflies, mexican bean beetles, and southern army worms.
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