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

2020 ◽  
Vol 37 (11) ◽  
pp. 3149-3164
Author(s):  
Shunyi Zhu ◽  
Bin Gao ◽  
Steve Peigneur ◽  
Jan Tytgat
Keyword(s):  
Pest Control ◽  
Design Principle ◽  
Hydrophobic Interactions ◽  
Interaction Model ◽  
Scorpion Toxin ◽  
Channel Interaction ◽  
Voltage Gated Sodium Channels ◽  
Arthropod Predators ◽  
Channel Opening ◽  
Chemical Pesticides

Abstract 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. Here, we show that the traditionally defined insect-selective scorpion toxin LqhIT2 specifically captures a prey Nav through a conserved trapping apparatus comprising a three-residue-formed cavity and a structurally adjacent leucine. The former serves as a detector to recognize and bind a highly exposed channel residue conserved in insects and spiders, two major prey items for scorpions; and the latter subsequently seizes the “moving” voltage sensor via hydrophobic interactions to reduce activation energy for channel opening, demonstrating its action in an enzyme-like manner. Based on the established toxin-channel interaction model in combination with toxicity assay, we enlarged the toxic spectrum of LqhIT2 to spiders and certain other arthropods. Furthermore, we found that genetic background-dependent cavity shapes determine the species selectivity of LqhIT2-related toxins. We expect that the discovery of the trapping apparatus will improve our understanding of the evolution and design principle of Nav-targeted toxins from a diversity of arthropod predators and accelerate their uses in pest control.

Scorpion toxin-potassium channel interaction law and its applications.

2020 ◽  
Vol 01 ◽  
Author(s):  
Zheng Zuo ◽  
Zongyun Chen ◽  
Zhijian Cao ◽  
Wenxin Li ◽  
Yingliang Wu
Keyword(s):  
Potassium Channel ◽  
Scorpion Toxin ◽  
Scorpion Toxins ◽  
Toxin Binding ◽  
Channel Interaction ◽  
Binding Interface ◽  
Α Helix ◽  
Interaction Law ◽  
Binding Interfaces ◽  
Β Sheet

: The scorpion toxins are the largest potassium channel-blocking peptide family. The understanding of toxin binding interfaces is usually restricted by two classical binding interfaces: one is the toxin α-helix motif, the other is the antiparallel β-sheet motif. In this review, such traditional knowledge was updated by another two different binding interfaces: one is BmKTX toxin using the turn motif between the α-helix and antiparallel β-sheet domains as the binding interface, the other is Ts toxin using turn motif between the β-sheet in the N-terminal and α-helix domains as the binding interface. Their interaction analysis indicated that the scarce negatively charged residues in the scorpion toxins played a critical role in orientating the toxin binding interface. In view of the toxin negatively charged amino acids as “binding interface regulator”, the law of scorpion toxin-potassium channel interaction was proposed, that is, the polymorphism of negatively charged residue distribution determines the diversity of toxin binding interfaces. Such law was used to develop scorpion toxin-potassium channel recognition control technique. According to this technique, three Kv1.3 channel-targeted peptides, using BmKTX as the template, were designed with the distinct binding interfaces from that of BmKTX through modulating the distribution of toxin negatively charged residues. In view of the potassium channel as the common targets of different animal toxins, the proposed law was also shown to helpfully orientate the binding interfaces of other animal toxins. Clearly, the toxin-potassium channel interaction law would strongly accelerate the research and development of different potassium channelblocking animal toxins in the future.

scholarly journals Structural basis for subtype-specific inhibition of the P2X7 receptor

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Akira Karasawa ◽  
Toshimitsu Kawate
Keyword(s):  
P2x7 Receptor ◽  
Hydrophobic Interactions ◽  
Binding Pocket ◽  
Drug Binding ◽  
Structural Basis ◽  
Atp Binding ◽  
Allosteric Site ◽  
Channel Opening ◽  
A Site ◽  
Novel Drug

The P2X7 receptor is a non-selective cation channel activated by extracellular adenosine triphosphate (ATP). Chronic activation of P2X7 underlies many health problems such as pathologic pain, yet we lack effective antagonists due to poorly understood mechanisms of inhibition. Here we present crystal structures of a mammalian P2X7 receptor complexed with five structurally-unrelated antagonists. Unexpectedly, these drugs all bind to an allosteric site distinct from the ATP-binding pocket in a groove formed between two neighboring subunits. This novel drug-binding pocket accommodates a diversity of small molecules mainly through hydrophobic interactions. Functional assays propose that these compounds allosterically prevent narrowing of the drug-binding pocket and the turret-like architecture during channel opening, which is consistent with a site of action distal to the ATP-binding pocket. These novel mechanistic insights will facilitate the development of P2X7-specific drugs for treating human diseases.

scholarly journals Konsep dan Implementasi Teknologi Budi Daya Ramah Lingkungan pada Tanaman Tembakau, Serat, dan Minyak Industri Concept and Implementation of Environmentally-Friendly Technologies in Cultivation of Tobacco, Fiber, and Industrial Oil Crops

2016 ◽  
Vol 1 (1) ◽  
pp. 41
Author(s):  
. Nurindah
Keyword(s):  
Pest Control ◽  
Insect Pests ◽  
Environmentally Friendly ◽  
Land Conservation ◽  
Technology Innovations ◽  
Industrial Oil ◽  
Oil Crops ◽  
Chemical Pesticides

<p>Penerapan teknologi ramah lingkungan budi daya tanaman pada suatu lahan akan dapat mempertahankan kelestarian lingkungan. Penciptaan teknologi budi daya tanaman tembakau, serat, dan minyak industri di-arahkan pada teknologi yang dapat meningkatkan produktivitas dan mutu hasil, efisiensi biaya usaha tani, dan ramah lingkungan. Teknologi ramah lingkungan difokuskan pada penemuan komponen teknologi prapa-nen yang mempunyai dampak minimal terhadap pencemaran atau perusakan lingkungan, yang meliputi va-rietas-varietas unggul, teknik pengendalian hama dan penyakit, teknik konservasi lahan tembakau. Varietas-varietas unggul tersebut adalah varietas-varietas yang mempunyai ketahanan terhadap hama dan penyakit, yaitu tembakau Prancak 95, Prancak N1, Prancak N2, Kemloko 2, dan Grompol Jatim 1; kapas: Kanesia 11–Kanesia 13; kenaf: Karangploso 14–Karangploso 15; wijen: Sumberrejo 4; dan jarak kepyar: Asembagus 81. Teknik pengendalian hama dan penyakit yang ramah lingkungan adalah teknologi pengendalian hama yang membatasi atau meniadakan penggunaan insektisida kimia sintetik dan menerapkan teknik pengendalian de-ngan memanfaatkan peran musuh alami serangga hama atau antagonis patogen penyebab penyakit, dan penggunaan pestisida nabati. Teknik konservasi lahan untuk mengendalikan erosi dan penyakit lincat dikem-bangkan pada lahan tembakau temanggung dengan menerapkan penggunaan varietas tahan penyakit, pem-buatan terassering dan penguatnya, pengolahan lahan minimal, dan aplikasi mikroba antagonis. Teknologi ramah lingkungan tersebut telah diterapkan di tingkat petani dan memberikan dampak yang positif terhadap pengembangan komoditas.</p><p>Technology innovations for tobacco, fibers, and industrial-oil crops are directed to increase production and quality of the products, efficiency, and environmentally-friendly technologies. The efficiency and environ-menttally-friendly technologies are focused on the pre-harvest technology innovations that have minimal im-pacts on environmental damages. The technologies include superior varieties, pest control, and land conser-vation. The superior varieties are those that resistant to either insect pests or diseases, i.e. tobacco: Prancak 95, Prancak N1, Prancak N2, Kemloko 2, and Grompol Jatim 1; cotton: Kanesia 11–Kanesia 13; kenaf: Ka-rangploso 14–Karangploso 15; sesame: Sumberrejo 4; and  castor: Asembagus 81.  Environmentally-friendly pest control is to limit or no use synthetic-chemical pesticides in pest control, but optimally make use the role of natural enemies and antagonists and use biopesticides. Land conservation technique to control erosi-on as well as ”lincat’ disease has been developed in fields of temanggung tobacco by using tobacco variety resistant to the disease, terracering, minimum tillage, and application of antagonist microbes. Those techno-logies has been implemented in the farmers’ fields and has a positive impacts for the commodity develop-ment.</p><p> </p>

Implementation of biological control

1988 ◽  
Vol 3 (2-3) ◽  
pp. 102-109 ◽  
Author(s):  
Joop C. van Lenteren
Keyword(s):  
Biological Control ◽  
Pest Control ◽  
Natural Enemies ◽  
Insect Pests ◽  
Control Program ◽  
Policy Makers ◽  
Future Developments ◽  
Industry Policy ◽  
Chemical Pesticides ◽  
Inoculative Biological Control

AbstractThe number of species of insect pests, estimated to be maximally 10,000 worldwide, forms only a small part of the millions of species of plant-eating insects. Chemical pest control is becoming increasingly difficult and objectionable in terms of environmental contamination so that other methods of pest control need to be developed. One of the best alternatives is biological control. Natural and inoculative biological control has already proven successful against a variety of pests over large areas. One is inclined to forget, however, how successful a biological control program has been as soon as the pest problem has been solved. Other types of biological control involving the regular introduction or augmentation of natural enemies are better known, although these have been applied on a much smaller scale; a survey of the present-day application of these latter types of biological control is presented here. Phases in the implementation of biological control are illustrated and needed future developments in research are discussed. The main limitation on the development of biological control is not the research, since natural enemies are easier found and with a much lower investment than new chemical pesticides, but rather the attitudes held by growers and disinterest on the part of industry, policy-makers, and politicians. The first priority for those concerned with the development and application of safer pest control should, therefore, be to change the perceptions that these other groups have of biological control.

scholarly journals Domain IV voltage-sensor movement is both sufficient and rate limiting for fast inactivation in sodium channels

2013 ◽  
Vol 142 (2) ◽  
pp. 101-112 ◽  
Author(s):  
Deborah L. Capes ◽  
Marcel P. Goldschen-Ohm ◽  
Manoel Arcisio-Miranda ◽  
Francisco Bezanilla ◽  
Baron Chanda
Keyword(s):  
Sodium Channels ◽  
Voltage Sensor ◽  
Fast Inactivation ◽  
Voltage Range ◽  
Voltage Gated Sodium Channels ◽  
Channel Opening ◽  
The Individual ◽  
Electrical Impulses ◽  
Voltage Sensing Domain ◽  
Rate Limiting

Voltage-gated sodium channels are critical for the generation and propagation of electrical signals in most excitable cells. Activation of Na+ channels initiates an action potential, and fast inactivation facilitates repolarization of the membrane by the outward K+ current. Fast inactivation is also the main determinant of the refractory period between successive electrical impulses. Although the voltage sensor of domain IV (DIV) has been implicated in fast inactivation, it remains unclear whether the activation of DIV alone is sufficient for fast inactivation to occur. Here, we functionally neutralize each specific voltage sensor by mutating several critical arginines in the S4 segment to glutamines. We assess the individual role of each voltage-sensing domain in the voltage dependence and kinetics of fast inactivation upon its specific inhibition. We show that movement of the DIV voltage sensor is the rate-limiting step for both development and recovery from fast inactivation. Our data suggest that activation of the DIV voltage sensor alone is sufficient for fast inactivation to occur, and that activation of DIV before channel opening is the molecular mechanism for closed-state inactivation. We propose a kinetic model of sodium channel gating that can account for our major findings over a wide voltage range by postulating that DIV movement is both necessary and sufficient for fast inactivation.

scholarly journals Mapping the β-Scorpion Toxin Receptor Site on Voltage-Gated Sodium Channels

2010 ◽  
Vol 98 (3) ◽  
pp. 108a-109a
Author(s):  
Zhongli Zhang ◽  
Izhar Karbat ◽  
Lior Cohen ◽  
Todd Scheuer ◽  
Dalia Gordon ◽  
...  
Keyword(s):  
Sodium Channels ◽  
Receptor Site ◽  
Scorpion Toxin ◽  
Voltage Gated ◽  
Voltage Gated Sodium Channels ◽  
Toxin Receptor

scholarly journals Is Our Food Safe from Pesticides?

EDIS ◽  
2013 ◽  
Vol 2013 (3) ◽  
Author(s):  
Frederick M. Fishel
Keyword(s):  
Pest Control ◽  
Environmental Protection Agency ◽  
Crop Protection ◽  
Economic Incentives ◽  
Control Methods ◽  
Protection Agency ◽  
Agricultural Community ◽  
Chemical Pesticides ◽  
The U.S

Growers of the food supply have adopted the use of integrated pest management (IPM) because it is no longer possible to rely solely on chemical pesticides to prevent unacceptable crop losses. According to the U.S. Environmental Protection Agency (EPA), IPM is the coordinated use of pest and environmental information and available pest control methods to prevent unacceptable levels of damage by the most economical means with the least possible hazard to people, property, and the environment. Scientific IPM strategies give the grower economic incentives for sustaining long-term crop protection with minimal disruption to the environment. The agricultural community typically will use pesticides sparingly as part of the IPM strategy whenever proven alternatives are not available for pest control. This 4-page fact sheet was written by Frederick M. Fishel, and published by the UF Department of Agronomy, March 2013. http://edis.ifas.ufl.edu/pi230

scholarly journals Toxicity of Granules of Bintaro Leaf Extract (Cerbera odollam Gaertn.) on Armyworm (Spodoptera litura Fab.)

BIOEDUKASI ◽  
2018 ◽  
pp. 15
Author(s):  
Ahmad Habib Sholahuddin ◽  
Wachju Subchan ◽  
Jekti Prihatin
Keyword(s):  
Pest Control ◽  
Spodoptera Litura ◽  
Leaf Extract ◽  
Insect Pests ◽  
Crop Productivity ◽  
Environmental Damage ◽  
Crop Failure ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Chemical Pesticides

Grayak caterpillar is insect pests that become pests of various food crops. Grayak caterpillars cause a decrease in crop productivity and even crop failure if they are not controlled. Pest control using chemical pesticides has many adverse effects on the environment. To minimize the occurrence of environmental damage, then it is used pest control using vegetable insecticides. Bintaro Leaf (Cerbera odollam Gaertn.) is potential as a vegetable insecticide. The purpose of this study was to examine the toxicity of granule from Bintaro leaf extract (C. odollam Gaertn.) on armyworms (S. litura Fab.). This research was a laboratory experimental research using Completely Randomized Design (CRD). Serial concentrations used in this study were 0% (control), 0.5%, 1%, 1.5%, 2%, and 2.5%. The results of this study showed that the granules of Bintaro leaf extract (C. odollam Gaertn.) were effective in causing mortality of armyworms (S. litura Fab.) at 1.5% concentration by 60% and included in toxic category. The value of LC50-48 hour granule from Bintaro leaf extract (C. odollam Gaertn) was 1.41%. Keywords: Spodoptera litura Fab. , Granula extract of Cerbera odollam Gaertn., Vegetable Insecticide.

scholarly journals EVALUASI PENGGUNAAN PESTISIDA PADA PETANI BAWANG MERAH DI DESA WOMBO MPANAU KECAMATAN TANANTOVEA KABUPATEN DONGGALA

2019 ◽  
Vol 9 (1) ◽  
pp. 26-32
Author(s):  
Tri Satyani ◽  
Arfan Arfan ◽  
Sayani Sayani
Keyword(s):  
Fusarium Wilt ◽  
Pest Control ◽  
Control Method ◽  
The Other ◽  
Primary Data ◽  
Right Action ◽  
Frequency Table ◽  
The Right ◽  
Chemical Pesticides ◽  
Random Method

This study aims to study and determine the behavior of farmers in the use of pesticides on shallots in Wombo Mpanau Village, Tanantovea District. This study uses a simple random method. The data obtained is collected, processed and analyzed. Analysis was carried out to determine the frequency of data in each variable. Primary data obtained through interviews were analyzed to provide a concise picture of groups of data in one frequency table. Types of pests that attack onion in Wombo Mpanau Village are leaf caterpillars, leaf flies, trips, flour dew, and fusarium wilt. The most widely used pest control method is the use of chemical pesticides, which reaches 70% of respondents. The knowledge of farmers on the application of pesticides is relatively good, namely 100% of respondents apply pesticides when there are symptoms of attack and if other controls are unable to overcome the pest attack. Knowledge of farmers on the use of doses of pesticides is relatively good, namely 100% of respondents use the dosage according to the recommendations listed on the packaging. The actions of farmers when applying pesticides in general are not mixing pesticides. The majority of respondents have taken the right action in terms of storing semrot and pesticides in a special place. But on the other hand the awareness of farmers is still low, because there are still many farmers who wash sprayers in rivers or ditches.

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