The Experts below are selected from a list of 4422 Experts worldwide ranked by ideXlab platform
Ke Dong - One of the best experts on this subject based on the ideXlab platform.
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molecular biology of insect sodium channels and pyrethroid resistance
Insect Biochemistry and Molecular Biology, 2014Co-Authors: Ke Dong, Yoshiko Nomura, Frank D Rinkevich, Lingxin Wang, Kristopher Silver, Boris S ZhorovAbstract:Voltage-gated sodium channels are essential for the initiation and propagation of the action potential in neurons and other excitable cells. Because of their critical roles in electrical signaling, sodium channels are targets of a variety of naturally occurring and synthetic neurotoxins, including several classes of insecticides. This review is intended to provide an update on the molecular biology of insect sodium channels and the molecular mechanism of pyrethroid resistance. Although mammalian and insect sodium channels share fundamental topological and functional properties, most insect species carry only one sodium channel gene, compared to multiple sodium channel genes found in each mammalian species. Recent studies showed that two posttranscriptional mechanisms, alternative splicing and RNA editing, are involved in generating functional diversity of sodium channels in insects. More than 50 sodium channel mutations have been identified to be responsible for or associated with knockdown resistance (kdr) to pyrethroids in various Arthropod Pests and disease vectors. Elucidation of molecular mechanism of kdr led to the identification of dual receptor sites of pyrethroids on insect sodium channels. Many of the kdr mutations appear to be located within or close to the two receptor sites. The accumulating knowledge of insect sodium channels and their interactions with insecticides provides a foundation for understanding the neurophysiology of sodium channels in vivo and the development of new and safer insecticides for effective control of Arthropod Pests and human disease vectors.
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molecular evidence for dual pyrethroid receptor sites on a mosquito sodium channel
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Yoshiko Nomura, Gul Satar, Ralf Nauen, Boris S Zhorov, Ke DongAbstract:Pyrethroid insecticides are widely used as one of the most effective control measures in the global fight against agricultural Arthropod Pests and mosquito-borne diseases, including malaria and dengue. They exert toxic effects by altering the function of voltage-gated sodium channels, which are essential for proper electrical signaling in the nervous system. A major threat to the sustained use of pyrethroids for vector control is the emergence of mosquito resistance to pyrethroids worldwide. Here, we report the successful expression of a sodium channel, AaNav1–1, from Aedes aegypti in Xenopus oocytes, and the functional examination of nine sodium channel mutations that are associated with pyrethroid resistance in various Ae. aegypti and Anopheles gambiae populations around the world. Our analysis shows that five of the nine mutations reduce AaNav1–1 sensitivity to pyrethroids. Computer modeling and further mutational analysis revealed a surprising finding: Although two of the five confirmed mutations map to a previously proposed pyrethroid-receptor site in the house fly sodium channel, the other three mutations are mapped to a second receptor site. Discovery of this second putative receptor site provides a dual-receptor paradigm that could explain much of the molecular mechanisms of pyrethroid action and resistance as well as the high selectivity of pyrethroids on insect vs. mammalian sodium channels. Results from this study could impact future prediction and monitoring of pyrethroid resistance in mosquitoes and other Arthropod Pests and disease vectors.
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diversity and convergence of sodium channel mutations involved in resistance to pyrethroids
Pesticide Biochemistry and Physiology, 2013Co-Authors: Frank D Rinkevich, Ke DongAbstract:Pyrethroid insecticides target voltage-gated sodium channels, which are critical for electrical signaling in the nervous system. The intensive use of pyrethroids in controlling Arthropod Pests and disease vectors has led to many instances of pyrethroid resistance around the globe. In the past two decades, studies have identified a large number of sodium channel mutations that are associated with resistance to pyrethroids. The purpose of this review is to summarize both common and unique sodium channel mutations that have been identified in Arthropod Pests of importance to agriculture or human health. Identification of these mutations provides valuable molecular markers for resistance monitoring in the field and helped the discovery of the elusive pyrethroid receptor site(s) on the sodium channel.
Joop C. Van Lenteren - One of the best experts on this subject based on the ideXlab platform.
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exotic biological control agents a solution or contribution to Arthropod invasions
Biological Invasions, 2016Co-Authors: Ann E Hajek, Joop C. Van Lenteren, Brett P Hurley, Marc Kenis, Jeffrey R Garnas, Samantha J Bush, Michael J Wingfield, Matthew J W CockAbstract:Biological control is a valuable and effective strategy for controlling Arthropod Pests and has been used extensively against invasive Arthropods. As one approach for control of invasives, exotic natural enemies from the native range of a pest are introduced to areas where control is needed. Classical biological control began to be used in the late 1800s and its use increased until, beginning in 1983, scientists began raising significant concerns and questions about nontarget and indirect effects that can be caused by these introductions. In recent years, similar issues have been raised about augmentative use of exotic natural enemies. Subsequently, international guidelines, national regulations and scientific methods being used for exotic natural enemies in biological control have changed to require appropriate specificity testing, risk assessment and regulatory oversight before exotic natural enemies can be released. National and international standards aimed at minimizing risk have increased awareness and promoted more careful consideration of the costs and benefits associated with biological control. The barriers to the implementation of classical and augmentative biological control with exotic natural enemies now are sometimes difficult and, as a consequence, the numbers of classical biological control programs and releases have decreased significantly. Based in part on this new, more careful approach, classical biological control programs more recently undertaken are increasingly aimed at controlling especially damaging invasive Arthropod Pests that otherwise cannot be controlled. We examine evidence for these revised procedures and regulations aimed at increasing success and minimizing risk. We also discuss limitations linked to the apparent paucity of post-introduction monitoring and inherent unpredictability of indirect effects.
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assessing risks of releasing exotic biological control agents of Arthropod Pests
Annual Review of Entomology, 2006Co-Authors: Joop C. Van Lenteren, Heikki M. T. Hokkanen, Jeffrey S. Bale, Franz Bigler, Antoon J M LoomansAbstract:More than 5000 introductions of about 2000 species of exotic Arthropod agents for control of Arthropod Pests in 196 countries or islands during the past 120 years rarely have resulted in negative environmental effects. Yet, risks of environmental effects caused by releases of exotics are of growing concern. Twenty countries have implemented regulations for release of biological control agents. Soon, the International Standard for Phytosanitary Measures (ISPM3) will become the standard for all biological control introductions worldwide, but this standard does not provide methods by which to assess environmental risks. This review summarizes documented nontarget effects and discusses the development and application of comprehensive and quick-scan environmental risk assessment methods.
Boris S Zhorov - One of the best experts on this subject based on the ideXlab platform.
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molecular biology of insect sodium channels and pyrethroid resistance
Insect Biochemistry and Molecular Biology, 2014Co-Authors: Ke Dong, Yoshiko Nomura, Frank D Rinkevich, Lingxin Wang, Kristopher Silver, Boris S ZhorovAbstract:Voltage-gated sodium channels are essential for the initiation and propagation of the action potential in neurons and other excitable cells. Because of their critical roles in electrical signaling, sodium channels are targets of a variety of naturally occurring and synthetic neurotoxins, including several classes of insecticides. This review is intended to provide an update on the molecular biology of insect sodium channels and the molecular mechanism of pyrethroid resistance. Although mammalian and insect sodium channels share fundamental topological and functional properties, most insect species carry only one sodium channel gene, compared to multiple sodium channel genes found in each mammalian species. Recent studies showed that two posttranscriptional mechanisms, alternative splicing and RNA editing, are involved in generating functional diversity of sodium channels in insects. More than 50 sodium channel mutations have been identified to be responsible for or associated with knockdown resistance (kdr) to pyrethroids in various Arthropod Pests and disease vectors. Elucidation of molecular mechanism of kdr led to the identification of dual receptor sites of pyrethroids on insect sodium channels. Many of the kdr mutations appear to be located within or close to the two receptor sites. The accumulating knowledge of insect sodium channels and their interactions with insecticides provides a foundation for understanding the neurophysiology of sodium channels in vivo and the development of new and safer insecticides for effective control of Arthropod Pests and human disease vectors.
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molecular evidence for dual pyrethroid receptor sites on a mosquito sodium channel
Proceedings of the National Academy of Sciences of the United States of America, 2013Co-Authors: Yoshiko Nomura, Gul Satar, Ralf Nauen, Boris S Zhorov, Ke DongAbstract:Pyrethroid insecticides are widely used as one of the most effective control measures in the global fight against agricultural Arthropod Pests and mosquito-borne diseases, including malaria and dengue. They exert toxic effects by altering the function of voltage-gated sodium channels, which are essential for proper electrical signaling in the nervous system. A major threat to the sustained use of pyrethroids for vector control is the emergence of mosquito resistance to pyrethroids worldwide. Here, we report the successful expression of a sodium channel, AaNav1–1, from Aedes aegypti in Xenopus oocytes, and the functional examination of nine sodium channel mutations that are associated with pyrethroid resistance in various Ae. aegypti and Anopheles gambiae populations around the world. Our analysis shows that five of the nine mutations reduce AaNav1–1 sensitivity to pyrethroids. Computer modeling and further mutational analysis revealed a surprising finding: Although two of the five confirmed mutations map to a previously proposed pyrethroid-receptor site in the house fly sodium channel, the other three mutations are mapped to a second receptor site. Discovery of this second putative receptor site provides a dual-receptor paradigm that could explain much of the molecular mechanisms of pyrethroid action and resistance as well as the high selectivity of pyrethroids on insect vs. mammalian sodium channels. Results from this study could impact future prediction and monitoring of pyrethroid resistance in mosquitoes and other Arthropod Pests and disease vectors.
Antoon J M Loomans - One of the best experts on this subject based on the ideXlab platform.
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assessing risks of releasing exotic biological control agents of Arthropod Pests
Annual Review of Entomology, 2006Co-Authors: Joop C. Van Lenteren, Heikki M. T. Hokkanen, Jeffrey S. Bale, Franz Bigler, Antoon J M LoomansAbstract:More than 5000 introductions of about 2000 species of exotic Arthropod agents for control of Arthropod Pests in 196 countries or islands during the past 120 years rarely have resulted in negative environmental effects. Yet, risks of environmental effects caused by releases of exotics are of growing concern. Twenty countries have implemented regulations for release of biological control agents. Soon, the International Standard for Phytosanitary Measures (ISPM3) will become the standard for all biological control introductions worldwide, but this standard does not provide methods by which to assess environmental risks. This review summarizes documented nontarget effects and discusses the development and application of comprehensive and quick-scan environmental risk assessment methods.
Geoff M Gurr - One of the best experts on this subject based on the ideXlab platform.
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silicon potential to promote direct and indirect effects on plant defense against Arthropod Pests in agriculture
Frontiers in Plant Science, 2016Co-Authors: Geoff M Gurr, Olivia L Reynolds, Matthew P Padula, Rensen ZengAbstract:Silicon has generally not been considered essential for plant growth, although it is well recognised that many plants, particularly Poacea, have substantial plant tissue concentrations of this element. Recently, however, the International Plant Nutrition Institute, Georgia, USA has listed it as a “beneficial substance”. This reflects the fact that numerous studies have now established that silicon may alleviate both biotic and abiotic stress. This paper explores existing knowledge and recent advances in elucidating the role of silicon in plant defence against biotic stress, particularly against Arthropod Pests in agriculture and attraction of beneficial insects. Silicon confers resistance to herbivory via two described mechanisms, physical and biochemical/molecular. Until recently, studies have mainly centered on two trophic levels, the herbivore and plant. However, several studies now describe tri-trophic effects involving silicon that operate by attracting predators or parasitoids to plants under herbivore attack. Indeed, it has been demonstrated that silicon-treated, Arthropod attacked plants display increased attractiveness to natural enemies, an effect that was reflected in elevated biological control in the field. The reported relationship between soluble silicon and the jasmonic acid (JA) defence pathway and JA and herbivore induced plant volatiles (HIPVs) suggest that soluble silicon may enhance the production of HIPVs. Further, it is feasible that silicon uptake may affect protein expression (or modify proteins structurally) so that they can produce additional, or modify, the HIPV profile of plants. Ultimately, understanding silicon under plant ecological, physiological, biochemical and molecular contexts will assist in fully elucidating the mechanisms behind silicon and plant response to biotic stress at both the bi- and tri-trophic levels.
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Arthropod prey of shelterbelt associated birds linking faecal samples with biological control of agricultural Pests
Australian Journal of Entomology, 2007Co-Authors: Sagrario Gamezvirues, Geoff M Gurr, Ronald S Bonifacio, Cilla Kinross, Anantanarayanan Raman, Helen I NicolAbstract:The value of insectivorous birds as agents for biological control of Arthropod Pests has been little studied, especially in Australia. This paper reports on the extent to which Arthropods from various pest and non-pest taxa feature in the diets of birds captured in farm shelterbelts in central western New South Wales. The parameters examined were the types of Arthropod fragments in bird faeces and percentage volume and frequency of occurrence of each component. The faecal data were compared with samples of the Arthropod fauna trapped in shelterbelts during the period the birds were captured. In 26 of 29 faecal samples, Arthropod fragments were the predominant components, the most common being from Coleoptera, Hymenoptera (especially Formicidae), Orthoptera and Araneae. The recogn- isable pest taxa in faecal samples were Scarabaeidae and wingless grasshopper Phaulacridium vittatum (Sjostedt) (Orthoptera: Acrididae). The results indicate that the native bird species common in farm shelterbelts preyed on a range of Arthropod taxa including several that are Pests of crops and pastures. Accordingly, conservation of birds in farmlands could contribute to suppression of Arthropod Pests.
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habitat management to conserve natural enemies of Arthropod Pests in agriculture
Annual Review of Entomology, 2000Co-Authors: Douglas A. Landis, Stephen D Wratten, Geoff M GurrAbstract:▪ Abstract Many agroecosystems are unfavorable environments for natural enemies due to high levels of disturbance. Habitat management, a form of conservation biological control, is an ecologically based approach aimed at favoring natural enemies and enhancing biological control in agricultural systems. The goal of habitat management is to create a suitable ecological infrastructure within the agricultural landscape to provide resources such as food for adult natural enemies, alternative prey or hosts, and shelter from adverse conditions. These resources must be integrated into the landscape in a way that is spatially and temporally favorable to natural enemies and practical for producers to implement. The rapidly expanding literature on habitat management is reviewed with attention to practices for favoring predators and parasitoids, implementation of habitat management, and the contributions of modeling and ecological theory to this developing area of conservation biological control. The potential to int...
