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Insect Bioassay

Man P Huynh, Lisa N Meihls, Bruce E Hibbard, Stephen L Lapointe, Randall P Niedz, Dalton C Ludwick, Thomas A Coudron
The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is the most serious insect pest of corn (Zea mays L.) in the United States and parts of Europe, and arguably one of the world's most expensive pests to control. Several diet formulations are currently used by industry and public researchers to evaluate WCR larvae in diet-toxicity bioassays. However, a publicly available diet that produces normative insects that are physiologically similar to WCR larvae reared on corn roots will accelerate development of management technologies...
2017: PloS One
Caroline S Gough, Grace M Fairlamb, Petra Bell, Ronald J Nachman, Neil Audsley, R Elwyn Isaac
Neuropeptides play an important role in the regulation of feeding in insects and offer potential targets for the development of new chemicals to control insect pests. A pest that has attracted much recent attention is the highly invasive Drosophila suzukii, a polyphagous pest that can cause serious economic damage to soft fruits. Previously we showed by mass spectrometry the presence of the neuropeptide myosuppressin (TDVDHVFLRFamide) in the nerve bundle suggesting that this peptide is involved in regulating the function of the crop, which in adult dipteran insects has important roles in the processing of food, the storage of carbohydrates and the movement of food into the midgut for digestion...
2017: PloS One
Zhi-Jun Zhang, Jing-Jing Zhang, Zhi-Yan Jiang, Guo-Hua Zhong
A series of novel β-carboline 1,3,4-oxadiazole derivatives were designed and synthesized, and the in vitro cytotoxic activity against Sf9 cells and growth inhibitory activity against Spodoptera litura were evaluated. Bioassay results showed that most of these compounds exhibited excellent in vitro cytotoxic activity. Especially, compound 37 displayed the best efficacy in vitro (IC50 = 3.93 μM), and was five-fold more potent than camptothecin (CPT) (IC50 = 18.95 μM). Moreover, compounds 5 and 37 could induce cell apoptosis and cell cycle arrest and stimulate Sf-caspase-1 activation in Sf9 cells...
October 29, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Travis L Calkins, Andrew DeLaat, Peter M Piermarini
In adult dipteran insects (flies), the crop is a diverticulum of the esophagus that serves as a food storage organ. The crop pumps stored contents into the alimentary canal for digestion and absorption. The pumping is mediated by peristaltic contractions of the crop musculature. In adult female mosquitoes, the crop (ventral diverticulum) selectively stores sugar solutions (e.g., nectar); proteinaceous blood meals by-pass the crop and are transferred directly to the midgut for digestion. The mechanisms that regulate crop contractions have never been investigated in mosquitoes...
October 28, 2017: Journal of Insect Physiology
Faiza Saleem, Abdul Rauf Shakoori
The Cry (crystal) proteins from Bacillus thuringiensis are known to have toxicity against a variety of insects and have been exploited to control insect pests through transgenic plants and biopesticides. B. thuringiensis SBS BT-1 carrying the cry2 genes was isolated from soil samples in Pakistan. The 2-kb full length cry2Ac gene was cloned, sequenced, and submitted to the EMBL DNA database (Accession No. AM292031). For expression analysis, Escherichia coli DH5α was transformed with the fragment sub-cloned in pET22b expression vector using NdeI and HindIII restriction sites, and later confirmed by restriction endonuclease analysis...
November 3, 2017: Toxins
Bernal Matarrita-Carranza, Rolando D Moreira-Soto, Catalina Murillo-Cruz, Marielos Mora, Cameron R Currie, Adrián A Pinto-Tomas
The evolutionary success of hymenopteran insects has been associated with complex physiological and behavioral defense mechanisms against pathogens and parasites. Among these strategies are symbiotic associations between Hymenoptera and antibiotic-producing Actinobacteria, which provide protection to insect hosts. Herein, we examine associations between culturable Actinobacteria and 29 species of tropical hymenopteran insects that span five families, including Apidae (bees), Vespidae (wasps), and Formicidae (ants)...
2017: Frontiers in Microbiology
Qinglv Wei, Yanru Du, Kai Jin, Yuxian Xia
Homeodomain transcription factor Ste12 is a key target activated by the pathogenic mitogen-activated-protein kinase pathway, and the activated Ste12p protein regulates downstream gene expression levels to modulate phenotypes. However, the functions of Ste12-like genes in entomopathogenic fungi remain poorly understood and little is known about the downstream genes regulated by Ste12. In this study, we characterized the functions of a Ste12 orthologue in Metarhizium acridum, MaSte12, and identified its downstream target genes...
December 2017: Applied Microbiology and Biotechnology
Desmi I Chandrasena, Ana M Signorini, Gustavo Abratti, Nicholas P Storer, Magdalena L Olaciregui, Analiza P Alves, Clinton D Pilcher
BACKGROUND: Transgenic maize (Zea mays L.) event TC1507 (Herculex® I insect protection), expressing Cry1F δ-endotoxin derived from Bacillus thuringiensis var. aizawai, was commercialized in 2003 in the Americas. Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) susceptibility to Cry1F was monitored annually across several regions in Argentina using diagnostic concentration bioassays. Reduced performance of TC1507 maize against S. frugiperda was reported in 2013. A resistant population was established in the laboratory and the dominance of Cry1F resistance was characterized...
October 26, 2017: Pest Management Science
Wilson R Valbon, Franciele M Cruz, Gabryele S Ramos, Hudson V V Tomé, Eugênio E Oliveira
Freshwater ecosystems provide environmental conditions for many arthropod species, including pests like mosquitoes and beneficial insects. Giant water bugs, Belostoma anurum (Hemiptera: Belostomatidae), are aquatic insects that provide biological control of mosquitoes and small vertebrates in freshwater environments. However, the application of insecticides aiming to control mosquitoes can lead to insecticide exposures of aquatic predators that can result in their death or significant reductions in their behavioral abilities...
October 10, 2017: Chemosphere
M Dastranj, E Borzoui, A R Bandani, O L Franco
The diamondback moth (Plutella xylostella) and small white cabbage butterfly (Pieris rapae) are the two main serious pests of cruciferous crops (Brassicaceae) that have developed resistance to chemical control methods. In order to avoid such resistance and also the adverse effects of chemical pesticides on the environment, alternative methods have usually been suggested, including the use of plant enzyme inhibitors. Here, the inhibitory effects of proteinaceous inhibitors extracted from wheat, canola, sesame, bean and triticale were evaluated against the digestive α-amylases, larval growth, development and nutritional indecs of the diamondback moth and small white cabbage butterfly...
October 17, 2017: Bulletin of Entomological Research
Wen Zhi Wang, Ben Peng Yang, Xiao Yan Feng, Zheng Ying Cao, Cui Lian Feng, Jun Gang Wang, Guo Ru Xiong, Lin Bo Shen, Jun Zeng, Ting Ting Zhao, Shu Zhen Zhang
Genetically modified crops which had been commercial applied extensively majorly are the insect resistance and herbicide tolerance events. In this study, the Bt insecticidal gene Cry1Ab, the glyphosate-tolerant gene EPSPS, and the selection marker gene PMI were combined into a single transferred DNA fragment and introduced into sugarcane by Agrobacterium-mediated transformation. Thirty-three resistant plantlets were obtained after selection using a PMI/mannose selection system. Thirty of these resistant plantlets were PCR positive for the three target genes...
2017: Frontiers in Plant Science
Xiao-Guan Zhu, Zhen-Jian Chu, Sheng-Hua Ying, Ming-Guang Feng
Krs is a class II lysyl-tRNA synthetase (KRS) that is involved in cytosolic protein synthesis in budding yeast but functionally has not been explored in filamentous fungi. Previous transcriptomic analysis has revealed that a Krs-coding gene is likely involved in pathogenesis of Beauveria bassiana, a classic insect pathogen as a global source of fungal insecticides. Here, we show that Krs is localized in the cytoplasm of hyphal cells and acts as a substantial virulence factor in B. bassiana. Deletion of krs resulted in 10-h delayed germination, decreased (15 %) thermotolerance, and lowered (46 %) UV-B resistance of aerial conidia despite limited impact on conidiation capacity and slight or inconspicuous influence on radial growth on rich and minimal media with different carbon (10 sugars/polyols) and nitrogen (17 amino acids) sources...
November 2017: Fungal Biology
Nilima Prabhaker, Steven Naranjo, Thomas Perring, Steven Castle
Generalist insect predators play an essential role in regulating the populations of Bemisia tabaci and other pests in agricultural systems, but may be affected negatively by insecticides applied for pest management. Evaluation of insecticide compatibility with specific predator species can provide a basis for making treatment decisions with the aim of conserving natural enemies. Eleven insecticides representing six modes of action groups were evaluated for toxicity against four predator species and at different developmental stages...
September 27, 2017: Journal of Economic Entomology
Xiuxia Li, Haiyan Shi, Xiwu Gao, Pei Liang
BACKGROUND: Uridine diphosphate-glucuronosyltransferases (UGTs), as multifunctional detoxification enzymes, play important roles in the biotransformation of various compounds. However, their roles in insecticide resistance are still unclear. This study presents a genome-wide identification of the UGTs in diamondback moth, Plutella xylostella (L.), a worldwide notorious insect pest of cruciferous crops. The possible roles of these UGTs in insecticide resistance were evaluated. RESULTS: A total of 21 putative UGTs in P...
October 13, 2017: Pest Management Science
Krzysztof Kowalski, Paweł Marciniak, Grzegorz Rosiński, Leszek Rychlik
BACKGROUND: Animal toxins can have medical and therapeutic applications. Principally, toxins produced by insects, arachnids, snakes and frogs have been characterized. Venomous mammals are rare, and their venoms have not been comprehensively investigated. Among shrews, only the venom of Blarina brevicauda has been analysed so far, and blarina toxin has been proven to be its main toxic component. It is assumed that Neomys fodiens employs its venom to hunt larger prey. However, the toxic profile, properties and mode of action of its venom are largely unknown...
2017: Frontiers in Zoology
Misbah Ashraf, Muhammad Farooq, Muhammad Shakeel, Naima Din, Shahbaz Hussain, Nadia Saeed, Qaiser Shakeel, Nasir Ahmed Rajput
The stored grain insects cause great damage to grains under storage conditions. Synthetic insecticides and fumigants are considered as key measures to control these stored grain insect pests. However, the major issue with these chemicals is grain contamination with chemical residues and development of resistance by insect pests to these chemicals. Biological control is considered as a potential alternative to chemical control especially with the use of pathogens, alone or in combination with selective insecticides...
October 10, 2017: Environmental Science and Pollution Research International
Nancy M Endersby-Harshman, Juli Rochmijati Wuliandari, Lawrence G Harshman, Verena Frohn, Brian J Johnson, Scott A Ritchie, Ary A Hoffmann
Although pesticide resistance is common in insect vectors of human diseases, the evolution of resistance might be delayed if management practices are adopted that limit selection of resistance alleles. Outbreaks of dengue fever have occurred in Queensland, Australia, since the late 1800s, leading to ongoing attempts to control the mosquito vector, Aedes aegypti (L.). Since the 1990s, pyrethroid insecticides have been used for this purpose, but have been applied in a strategic manner with a variety of delivery methods including indoor residual spraying, lethal ovitraps, and use of insect growth regulators as larvicides...
November 7, 2017: Journal of Medical Entomology
Xue Chang, Zengbin Lu, Zhicheng Shen, Yufa Peng, Gongyin Ye
Harmonia axyridis (Pallas) is a common and abundant predator in China and may be exposed to Cry toxins that are produced in Bt crops either by feeding on plant parts or by feeding on target or nontarget herbivorous insects. A new Bt maize line, expressing the Cry1Ab/Cry2Aj fused protein, has been developed and should be rigorously assessed for the ecological risks on the natural enemy. Laboratory experiments were carried out to study the effects of this Bt maize on nontarget predator H. axyridis via bitrophic interaction of adult H...
October 1, 2017: Environmental Entomology
Arshia Hematpoor, Sook Yee Liew, Mohd Sofian Azirun, Khalijah Awang
Hexane, dichloromethane and methanol extracts of the roots of Piper sarmentosum Roxb. were screened for toxicity towards Sitophilus oryzae (L.), Rhyzopertha dominica (F.), and Plodia interpunctella (Hübner) and the hexane extract exhibited the highest mortality percentage. Bioassay-guided fractionation of the hexane extract resulted in the isolation of asaricin 1, isoasarone 2, and trans-asarone 3. Asaricin 1 and isoasarone 2 were the most toxic compounds to Sitophilus oryzae, Rhyzopertha dominica, and Plodia interpunctella...
October 3, 2017: Scientific Reports
Xiudao Yu, Nabil Killiny
BACKGROUND: Asian citrus psyllid, Diaphorina citri Kuwayama, is an important agricultural pest of citrus globally. Foliar application of chemical insecticides is the most widely followed option for reducing D. citri populations. Knockdown of glutathione S-transferase (GST) in several insect species leads to increased susceptibility to insecticides, however, information about the detoxifying role of GST genes in D. citri is unavailable. RESULTS: Via a sequence homology search, we isolated and characterized three DcGST genes (DcGSTd1, DcGSTe1 and DcGSTe2) from D...
October 3, 2017: Pest Management Science
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