16 results match your criteria insect navs

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Kdr genotyping in Aedes aegypti from Brazil on a nation-wide scale from 2017 to 2018.

Sci Rep 2020 08 6;10(1):13267. Epub 2020 Aug 6.

Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz, FIOCRUZ, Rio de Janeiro, RJ, Brazil.

Insecticide resistance is currently a threat to the control of Aedes agypti, the main vector of arboviruses in urban centers. Mutations in the voltage gated sodium channel (Na), known as kdr (knockdown resistance), constitute an important selection mechanism for resistance against pyrethroids. In the present study, we investigated the kdr distribution for the Val1016Ile and Phe1534Cys alterations in Ae. Read More

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How a Scorpion Toxin Selectively Captures a Prey Sodium Channel: The Molecular and Evolutionary Basis Uncovered.

Mol Biol Evol 2020 11;37(11):3149-3164

Department of Toxicology and Pharmacology, University of Leuven (KU Leuven), Leuven, Belgium.

The growing resistance of insects to chemical pesticides is reducing the effectiveness of conventional methods for pest control and thus, the development of novel insecticidal agents is imperative. Scorpion toxins specific for insect voltage-gated sodium channels (Navs) have been considered as one of the most promising insecticide alternatives due to their host specificity, rapidly evoked toxicity, biodegradability, and the lack of resistance. However, they have not been developed for uses in agriculture and public health, mainly because of a limited understanding of their molecular and evolutionary basis controlling their phylogenetic selectivity. Read More

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November 2020

Evaluation of resistance to pyrethroid and organophosphate adulticides and kdr genotyping in Aedes aegypti populations from Roraima, the northernmost Brazilian State.

Parasit Vectors 2020 May 20;13(1):264. Epub 2020 May 20.

Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz, FIOCRUZ, Av Brasil 4365, Manguinhos, Rio de Janeiro, RJ, Brazil.

Background: Roraima, the northernmost State in Brazil, borders Venezuela and Guyana. Although mostly covered by the tropical forests, the urban centers of this state are highly infested with Ae. aegypti and are endemic for dengue, Zika and chikungunya. Read More

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Evaluation of insecticide resistance in Aedes aegypti populations connected by roads and rivers: the case of Tocantins state in Brazil.

Mem Inst Oswaldo Cruz 2019 Mar 25;114:e180318. Epub 2019 Mar 25.

Fundação Oswaldo Cruz-Fiocruz, Instituto Oswaldo Cruz, Laboratório de Fisiologia e Controle de Artrópodes Vetores, Rio de Janeiro, RJ, Brasil.

Background: The longstanding application of insecticides for vector control without periodic monitoring of the population response to these chemicals can directly drive the selection of resistant populations of vector mosquitoes. Tocantins is the newest state of the Brazilian Federation. Despite a historically high number of dengue cases, studies and monitoring data concerning insecticide resistance in the state are lacking. Read More

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Electrophysiological characterization of Tityus obscurus β toxin 1 (To1) on Na-channel isoforms.

Biochim Biophys Acta Biomembr 2019 01 14;1861(1):142-150. Epub 2018 Aug 14.

Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Distrito Federal, Brazil. Electronic address:

To1, previously named Tc49b, is a peptide neurotoxin isolated from venom of the scorpion Tityus obscurus that is responsible for lethal human poisoning cases in the Brazilian Amazonian region. Previously, To1 was shown to be lethal to mice and to change Na permeation in cerebellum granular neurons from rat brain. In addition, To1 did not affect Shaker B K channels. Read More

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January 2019

Purification and Characterization of a Novel Insecticidal Toxin, μ-sparatoxin-Hv2, from the Venom of the Spider .

Toxins (Basel) 2018 06 7;10(6). Epub 2018 Jun 7.

The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha 410081, China.

The venom of the spider produced lethal effect to cockroaches as reported in our previous study, and could be a resource for naturally-occurring insecticides. The present study characterized a novel cockroach voltage-gated sodium channels (Nas) antagonist, μ-sparatoxin-Hv2 (μ-SPRTX-Hv2 for short), from this venom. μ-SPRTX-Hv2 is composed of 37 amino acids and contains six conserved cysteines. Read More

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The peptide toxin δ-hexatoxin-MrIX inhibits fast inactivation of Nas in mouse cerebellar granule cells.

Peptides 2018 04 6;102:47-53. Epub 2018 Mar 6.

The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, 410081, China. Electronic address:

Spider venom is rich in peptide toxins that could be used to explore the structure and function of voltage-gated sodium channels (Nas). This study has characterized a 44-amino acid peptide toxin, δ-hexatoxin-MrIX (δ-HXTX-MrIX), from the venom of the spider Macrothele raveni. δ-hexatoxin-MrIX potently inhibited the fast inactivation of Nas in mouse cerebellar granule cells (CGCs) with an EC of 35. Read More

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Characterization of an insect heterodimeric voltage-gated sodium channel with unique alternative splicing mode.

Comp Biochem Physiol B Biochem Mol Biol 2017 Jan 3;203:149-158. Epub 2016 Nov 3.

Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400715, PR China. Electronic address:

Recent discovery of the heterodimeric voltage-gated sodium channels (Na) in two aphid species, Acyrthosiphon pisum and Myzus persicae, aroused interest in exploring whether this kind of channel is conserved for aphids. Herewith, we aim to provide evidence for the conservation of heterodimeric Nas in aphids and investigate whether they have unique splicing patterns. We found that the only identifiable Na from Toxoptera citricida consisted of two subunits, forming a heterodimeric Na, which carried an atypical "DENS" ion selectivity filter and a conventional "MFM" inactivation gate, confirming the heterodimeric Nas' conservation within aphids. Read More

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January 2017

Controlled banked turns in coleopteran flight measured by a miniature wireless inertial measurement unit.

Bioinspir Biomim 2016 09 28;11(5):056018. Epub 2016 Sep 28.

School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, Singapore.

The mechanisms and principles of insect flight have long been investigated by researchers working on micro and nano air vehicles (MAVs/NAVs). However, studies of insect flight maneuvers require high speed filming and high spatial resolution in a small experimental space, or the tethering of the insect to a fixed place. Under such artificial conditions, the insects may deviate its flying behavior from that of regular flight. Read More

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September 2016

The specificity of Av3 sea anemone toxin for arthropods is determined at linker DI/SS2-S6 in the pore module of target sodium channels.

Biochem J 2014 Oct;463(2):271-7

*Department of Plant Molecular Biology & Ecology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.

Av3 is a peptide neurotoxin from the sea anemone Anemonia viridis that shows specificity for arthropod voltage-gated sodium channels (Navs). Interestingly, Av3 competes with a scorpion α-toxin on binding to insect Navs and similarly inhibits the inactivation process, and thus has been classified as 'receptor site-3 toxin', although the two peptides are structurally unrelated. This raises questions as to commonalities and differences in the way both toxins interact with Navs. Read More

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October 2014

Distribution and dissemination of the Val1016Ile and Phe1534Cys Kdr mutations in Aedes aegypti Brazilian natural populations.

Parasit Vectors 2014 Jan 15;7:25. Epub 2014 Jan 15.

Laboratório de Fisiologia e Controle de Artrópodes Vetores, Instituto Oswaldo Cruz - FIOCRUZ, Rio de Janeiro, RJ, Brazil.

Background: The chemical control of the mosquito Aedes aegypti, the major vector of dengue, is being seriously threatened due to the development of pyrethroid resistance. Substitutions in the 1016 and 1534 sites of the voltage gated sodium channel (AaNaV), commonly known as kdr mutations, confer the mosquito with knockdown resistance. Our aim was to evaluate the allelic composition of natural populations of Brazilian Ae. Read More

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January 2014

Two recombinant α-like scorpion toxins from Mesobuthus eupeus with differential affinity toward insect and mammalian Na(+) channels.

Biochimie 2013 Sep 4;95(9):1732-40. Epub 2013 Jun 4.

Group of Animal Innate Immunity, State Key Laboratory of Integrated Management of Pest, Insects & Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.

α-Scorpion toxins are modulators of voltage-gated Na(+) channels (Navs), which bind to the receptor site 3 to inhibit the fast inactivation of the channels. MeuNaTxα-12 and MeuNaTxα-13 are two new α-scorpion toxin-like peptides identified by cDNA cloning from the scorpion Mesobuthus eupeus with unknown functions. Here, we report their recombinant production, oxidative refolding, structural and functional features. Read More

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September 2013

Remote radio control of insect flight.

Front Integr Neurosci 2009 5;3:24. Epub 2009 Oct 5.

Department of Electrical Engineering and Computer Science, University of California at Berkeley Berkeley, CA, USA.

We demonstrated the remote control of insects in free flight via an implantable radio-equipped miniature neural stimulating system. The pronotum mounted system consisted of neural stimulators, muscular stimulators, a radio transceiver-equipped microcontroller and a microbattery. Flight initiation, cessation and elevation control were accomplished through neural stimulus of the brain which elicited, suppressed or modulated wing oscillation. Read More

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NMR analysis of interaction of LqhalphaIT scorpion toxin with a peptide corresponding to the D4/S3-S4 loop of insect para voltage-gated sodium channel.

Biochemistry 2008 Jan 23;47(3):911-21. Epub 2007 Dec 23.

Department of Structural Biology, Weizmann Institute of Science, Rehovot 76100, Israel.

Voltage-gated sodium channels (Navs) are large transmembrane proteins that initiate action potential in electrically excitable cells. This central role in the nervous system has made them a primary target for a large number of neurotoxins. Scorpion alpha-neurotoxins bind to Navs with high affinity and slow their inactivation, causing a prolonged action potential. Read More

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January 2008

Nonhost angiosperm volatiles and verbenone disrupt response of western pine beetle, Dendroctonus brevicomis (Coleoptera: Scolytidae), to attractant-baited traps.

J Econ Entomol 2005 Dec;98(6):2041-8

Pacific Southwest Research Station, USDA Forest Service, Davis, CA 95616, USA.

Nonhost angiosperm volatiles and verbenone were tested for their ability to disrupt the response of western pine beetle, Dendroctonus brevicomis LeConte (Coleoptera: Scolytidae), to attractant-baited multiple funnel traps. Verbenone significantly reduced attraction; however, no difference was observed between 4 and 50 mg/24-h release rates. Combinations of six bark volatiles (benzyl alcohol, benzaldehyde, trans-conophthorin, guaiacol, nonanal, and salicylaldehyde), three green leaf volatiles [(E)-2-hexenal, (E)-2-hexen-1-ol, and (Z)-2-hexen-1-ol], and the nine compounds combined did not significantly reduce D. Read More

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December 2005

Common features in the functional surface of scorpion beta-toxins and elements that confer specificity for insect and mammalian voltage-gated sodium channels.

J Biol Chem 2005 Feb 29;280(6):5045-53. Epub 2004 Nov 29.

Department of Plant Sciences, George S. Wise Faculty of Life Sciences, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv 69978, Tel-Aviv, Israel.

Scorpion beta-toxins that affect the activation of mammalian voltage-gated sodium channels (Navs) have been studied extensively, but little is known about their functional surface and mode of interaction with the channel receptor. To enable a molecular approach to this question, we have established a successful expression system for the anti-mammalian scorpion beta-toxin, Css4, whose effects on rat brain Navs have been well characterized. A recombinant toxin, His-Css4, was obtained when fused to a His tag and a thrombin cleavage site and had similar binding affinity for and effect on Na currents of rat brain sodium channels as those of the native toxin isolated from the scorpion venom. Read More

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February 2005
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