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https://www.readbyqxmd.com/read/30326263/new-perspectives-on-mega-plasmid-sequence-poh1-in-bacillus-thuringiensis-atcc-10792-harbouring-antimicrobial-insecticidal-and-antibiotic-resistance-genes
#1
Ramachandran Chelliah, Byung-Jae Park, Shuai Wei, Joong-Hyun Park, Youn-Seo Park, Se-Hun Kim, Yong-Guo Jin, Deog-Hwan Oh
Bacillus thuringiensis promotes the growth of numerous economically important crops. The present study presents the complete genome sequence for a mega plasmid present in the type strain of B. thuringiensis ATCC 10792, a typical spore-forming Gram-positive bacterium with insecticidal activity, and investigates its genetic characteristics. The genome was sequenced and assembled de novo using Pac-Bio sequencers and the Hierarchical Genome Assembly Process, respectively. Further genome annotation was performed, and a total of 489 proteins and a novel mega-plasmid (poh1) with 584,623 bps were identified...
October 13, 2018: Microbial Pathogenesis
https://www.readbyqxmd.com/read/30323822/relative-selectivity-of-plant-cardenolides-for-na-k-atpases-from-the-monarch-butterfly-and-non-resistant-insects
#2
Georg Petschenka, Colleen S Fei, Juan J Araya, Susanne Schröder, Barbara N Timmermann, Anurag A Agrawal
A major prediction of coevolutionary theory is that plants may target particular herbivores with secondary compounds that are selectively defensive. The highly specialized monarch butterfly ( Danaus plexippus ) copes well with cardiac glycosides (inhibitors of animal Na+ /K+ -ATPases) from its milkweed host plants, but selective inhibition of its Na+ /K+ -ATPase by different compounds has not been previously tested. We applied 17 cardiac glycosides to the D. plexippus -Na+ /K+ -ATPase and to the more susceptible Na+ /K+ -ATPases of two non-adapted insects ( Euploea core and Schistocerca gregaria )...
2018: Frontiers in Plant Science
https://www.readbyqxmd.com/read/30293960/anti-tumor-activity-of-escherichia-coli-shiga-toxin-a-subunit-delivered-by-sf9-insect-cells
#3
Mana Oloomi, Maryam Imani, Ramezan Behzadi, Mohsen Asori, Saeid Bouzari, Bita Mokhlesi
Cancer remains a major health problem around the world. A Shiga toxin is a bacterial toxin often produced by Shigella dysenteriae and Escherichia coli. A subunit of the Shiga toxin (StxA) is a cytotoxic agent which could be used to induce death in cancer cells. StxA expressed from baculovirus was evaluated in a pTriEx™ expression vector. The baculovirus vector was used for the A subunit delivery of StxA. StxA cell cytotoxicity was induced by the virus and assessed in the MCF7 and HeLa cell lines. In addition, the breast cancer cytotoxicity of the expressed StxA was also assessed in a cancer induced in mice...
September 22, 2018: Journal of Pharmacological Sciences
https://www.readbyqxmd.com/read/30290365/toxin-diversity-revealed-by-the-venom-gland-transcriptome-of-pardosa-pseudoannulata-a-natural-enemy-of-several-insect-pests
#4
Lixin Huang, Zhaoying Wang, Na Yu, Jingjing Li, Zewen Liu
The pond wolf spider, Pardosa pseudoannulata, is one of the most dominant predators of several agriculture insect pests including mainly the rice planthoppers and leafhoppers in paddy fields in Asia. Venom has been an attractive subject as the powerful weapon of spiders due to the complex components secreted from venom gland. The transcriptome of P. pseudoannulata venom gland was sequenced in order to understand the diversity of venom components at the molecular level and provide a new perspective for insect pest management...
September 22, 2018: Comparative Biochemistry and Physiology. Part D, Genomics & Proteomics
https://www.readbyqxmd.com/read/30278206/bacillus-thuringiensis-cry1a-toxins-exert-toxicity-by-multiple-pathways-in-insects
#5
Shaohua Wang, Wendy Kain, Ping Wang
Adoption of biotech crops engineered to express insecticidal toxins from Bacillus thuringiensis (Bt) has revolutionized insect pest control in agriculture. For continuing effective application and development of the environmentally friendly Bt biotechnology, it is fundamental to understand pathways of toxicity of Bt toxins in insects. In this study, mutations were introduced in the midgut cadherin gene in the cabbage looper, Trichoplusia ni, by CRISPR/Cas9 mutagenesis. T. ni strains with mutations in the genes of two major receptors for Bt toxins, the midgut cadherin and ABCC2, and three Cry1A toxins with shared and differential midgut binding sites were used as an experimental system to dissect the roles of the cadherin and ABCC2 in the pathways of toxicity of Bt toxins...
September 29, 2018: Insect Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/30278182/a-37-kda-txp40-protein-characterized-from-photorhabdus-luminescens-sub-sp-akhurstii-conferred-injectable-and-oral-toxicity-to-greater-wax-moth-galleria-mellonella
#6
Chetna Mathur, Jyoti Kushwah, Vishal S Somvanshi, Tushar K Dutta
Photorhabdus luminescens is a gram-negative bacterium that symbiotically associates with insect-parasitic nematode, Heterorhabditis indica. Herein, we have characterized an insecticidal gene, Txp40 (1008 bp) from the indigenous isolates of P. luminescens, and tested its bioefficacy against Galleria mellonella via injectable and oral bioassay. The recombinant protein characterized from P. luminescens strain H3 exhibited comparatively greater insect toxicity than strain H1 in terms of LD50 and LT50 values. Txp40 holds great potential to replace Bt toxins in global agriculture...
September 29, 2018: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/30269215/probing-active-microbes-involved-in-bt-containing-rice-straw-decomposition
#7
Qicheng Xu, Rongbo Dai, Yang Ruan, Christopher Rensing, Manqiang Liu, Shiwei Guo, Ning Ling, Qirong Shen
Transgenic Bacillus thuringiensis (Bt) rice extends significant protection against insect pests and meets the increasing demands for food and energy. Many studies have been conducted investigating the impacts of Bt rice to the agricultural ecosystem, but much less attention has been given to efforts attempting to determine how the presence of Bt rice influences and shapes the microbial community, especially the active microbes. Stable isotope probing and high-throughput sequencing were employed to explore the active microbes involved in Bt-containing straw decomposition...
September 29, 2018: Applied Microbiology and Biotechnology
https://www.readbyqxmd.com/read/30261235/manipulation-of-the-silkworm-immune-system-by-a-metalloprotease-from-the-pathogenic-bacterium-pseudomonas-aeruginosa
#8
Li Ma, Lizhen Zhou, Jinshui Lin, Jiuyuan Ji, Yang Wang, Haobo Jiang, Xihui Shen, Zhiqiang Lu
Antimicrobial peptide (AMP) production and melanization are two key humoral immune responses in insects. Induced synthesis of AMPs results from Toll and IMD signal transduction whereas melanization depends on prophenoloxidase (PPO) activation system. During invasion, pathogens produce toxins and other virulent factors to counteract host immune responses. Here we show that the pathways leading to PPO activation and AMP synthesis in the silkworm Bombyx mori are affected by a metalloprotease, named elastase B, secreted by Pseudomonas aeruginosa (PAO1)...
September 24, 2018: Developmental and Comparative Immunology
https://www.readbyqxmd.com/read/30257487/c-type-lectin-20-interacts-with-alp1-receptor-to-reduce-cry-toxicity-in-aedes-aegypti
#9
Khadija Batool, Intikhab Alam, Guohui Zhao, Junxiang Wang, Jin Xu, Xiaoqiang Yu, Enjiong Huang, Xiong Guan, Lingling Zhang
Aedes aegypti is a crucial vector for human diseases, such as yellow fever, dengue, chikungunya, and Zika viruses. Today, a major challenge throughout the globe is the insufficient availability of antiviral drugs and vaccines against arboviruses, and toxins produced by Bacillus thuringiensis (Bt) are still used as biological agents for mosquito control. The use of Cry toxins to kill insects mainly depends on the interaction between Cry toxins and important toxin receptors, such as alkaline phosphatase (ALP)...
September 25, 2018: Toxins
https://www.readbyqxmd.com/read/30236155/enhancement-of-insect-susceptibility-and-larvicidal-efficacy-of-cry4ba-toxin-by-calcofluor
#10
Somphob Leetachewa, Narumol Khomkhum, Somsri Sakdee, Ping Wang, Saengduen Moonsom
BACKGROUND: Mosquitoes transmit many vector-borne infectious diseases including malaria, dengue, chikungunya, yellow fever, filariasis, and Japanese encephalitis. The insecticidal δ-endotoxins Cry4, Cry11, and Cyt produced from Bacillus thuringiensis have been used for bio-control of mosquito larvae. Cry δ-endotoxins are synthesised as inactive protoxins in the form of crystalline inclusions in which they are processed to active toxins in larval midgut lumen. Previously, we demonstrated that the activated Cry4Ba toxin has to alter the permeability of the peritrophic membrane (PM), allowing toxin passage across PM to reach specific receptors on microvilli of larval midgut epithelial cells, where the toxin undergoes conformational changes, followed by membrane insertion and pore formation, resulting in larval death...
September 20, 2018: Parasites & Vectors
https://www.readbyqxmd.com/read/30230081/lineage-specific-duplication-and-adaptive-evolution-of-bitter-taste-receptor-genes-in-bats
#11
Hengwu Jiao, Yi Wang, Libiao Zhang, Peihua Jiang, Huabin Zhao
By generating raw genetic material and diverse biological functions, gene duplication represents a major evolutionary mechanism that is of fundamental importance in ecological adaptation. The lineage-specific duplication events of bitter taste receptor genes (Tas2rs) have been identified in a number of vertebrates, but functional evolution of new Tas2r copies after duplication remains largely unknown. Here we present the largest data set of bat Tas2rs to date, identified from existing genome sequences of 15 bat species and newly sequenced from 17 bat species, and demonstrate lineage-specific duplications of Tas2r16, Tas2r18 and Tas2r41 that only occurred in Myotis bats...
September 19, 2018: Molecular Ecology
https://www.readbyqxmd.com/read/30194925/protein-probes-to-visualize-sphingomyelin-and-ceramide-phosphoethanolamine
#12
REVIEW
Françoise Hullin-Matsuda, Motohide Murate, Toshihide Kobayashi
Sphingomyelin (SM) is a major sphingolipid in mammalian cells whereas its analog, ceramide phosphoethanolamine (CPE) is found in trace amounts in mammalian cells and in larger amounts in invertebrates such as insect cells like Drosophila melanogaster. To visualize endogenous SM or CPE, we need specific probes able to recognize the chemical structure of the lipid, rather than its physical property. A limited number of proteins is known to specifically and strongly bind SM or CPE. These proteins are either toxins produced by non-mammalian organisms, subunits or fragments of toxins or a protein that has similar structure to a toxin...
November 2018: Chemistry and Physics of Lipids
https://www.readbyqxmd.com/read/30175130/combinational-effect-of-rumex-tingitanus-polygonaceae-hexane-extract-and-bacillus-thuringiensis-%C3%AE-endotoxin-against-spodoptera-littoralis-lepidoptera-noctuidae
#13
Dhekra Mhalla, Dalel Ben Farhat-Touzri, Slim Tounsi, Mohamed Trigui
The increasing insect resistance against Bacillus thuringiensis delta-endotoxins is a serious problem which makes it urgent to look for new eco-friendly strategies. Combining these toxins with other biomolecules is one of the promising strategies against insect pests. In this work, we evaluated the bioinsecticidal potential of Rumex tingitanus extracts and B. thuringiensis strain BLB250 against Spodoptera littoralis (Lepidoptera: Noctuidae) larvae. The chemical composition of the hexane extract, the most active fraction, was analyzed to validate the correlation between chemical composition and biological activity...
2018: BioMed Research International
https://www.readbyqxmd.com/read/30169799/biological-evaluation-of-endothall-a-dicarboxylic-acid-analog-of-norcantharidin-and-cantharidin-on-oriental-leafworm-spodoptera-litura-lepidoptera-noctuidae
#14
Hassan Yasoob, Rashid Ahmed Khan, Muhammed Naveed, Maryam Rashid, Yalin Zhang
Cantharidin is a highly potent toxin produced by insects belonging to the order Coleoptera and family Meloidae. The insecticidal activity of cantharidin against different orders of insects has been well documented. Although it is highly effective, its extraction and synthesis is very tedious. Consequently, much work is underway to synthesize the bioactive analogs of norcantharidin and study their relative structures. In this study, we investigate the acute and chronic toxicological effects of cantharidin and endothall, an analog of norcantharidin, using an age-stage-based two-sex life table methodology...
August 30, 2018: Journal of Economic Entomology
https://www.readbyqxmd.com/read/30158303/foraging-bumblebees-acquire-a-preference-for-neonicotinoid-treated-food-with-prolonged-exposure
#15
Andres N Arce, Ana Ramos Rodrigues, Jiajun Yu, Thomas J Colgan, Yannick Wurm, Richard J Gill
Social bees represent an important group of pollinating insects that can be exposed to potentially harmful pesticides when foraging on treated or contaminated flowering plants. To investigate if such exposure is detrimental to bees, many studies have exclusively fed individuals with pesticide-spiked food, informing us about the hazard but not necessarily the risk of exposure. While such studies are important to establish the physiological and behavioural effects on individuals, they do not consider the possibility that the risk of exposure may change over time...
August 29, 2018: Proceedings. Biological Sciences
https://www.readbyqxmd.com/read/30137474/field-study-investigating-cry51aa2-834_16-in-cotton-for-control-of-thrips-thysanoptera-thripidae-and-tarnished-plant-bugs-hemiptera-miridae
#16
Scott H Graham, Scott D Stewart
Field experiments were conducted in 2016 and 2017 in Tennessee to evaluate the effects of a novel Bacillus thuringiensis (Bt)-transgenic toxin, Bt Cry51Aa2.834_16, on thrips (Thysanoptera: Thripidae) and tarnished plant bug, Lygus lineolaris (Palisot De Beauvois) (Hemiptera: Miridae), in cotton. Protection from thrips injury with the Bt trait was as good or better than an insecticide-based approach. The use of the Bt trait resulted in reduced numbers of immature tarnished plant bug, particularly large nymphs, and partial protection from plant bug injury...
August 22, 2018: Journal of Economic Entomology
https://www.readbyqxmd.com/read/30134593/-phoneutria-nigriventer-spider-toxin-pntx2-1-%C3%AE-ctenitoxin-pn1a-is-a-modulator-of-sodium-channel-gating
#17
Steve Peigneur, Ana Luiza B Paiva, Marta N Cordeiro, Márcia H Borges, Marcelo R V Diniz, Maria Elena de Lima, Jan Tytgat
Spider venoms are complex mixtures of biologically active components with potentially interesting applications for drug discovery or for agricultural purposes. The spider Phoneutria nigriventer is responsible for a number of envenomations with sometimes severe clinical manifestations in humans. A more efficient treatment requires a comprehensive knowledge of the venom composition and of the action mechanism of the constituting components. PnTx2-1 (also called δ-ctenitoxin-Pn1a) is a 53-amino-acid-residue peptide isolated from the venom fraction PhTx2...
August 21, 2018: Toxins
https://www.readbyqxmd.com/read/30127293/comparative-genomics-and-description-of-putative-virulence-factors-of-melissococcus-plutonius-the-causative-agent-of-european-foulbrood-disease-in-honey-bees
#18
Marvin Djukic, Silvio Erler, Andreas Leimbach, Daniela Grossar, Jean-Daniel Charrière, Laurent Gauthier, Denise Hartken, Sascha Dietrich, Heiko Nacke, Rolf Daniel, Anja Poehlein
In Europe, approximately 84% of cultivated crop species depend on insect pollinators, mainly bees. Apis mellifera (the Western honey bee) is the most important commercial pollinator worldwide. The Gram-positive bacterium Melissococcus plutonius is the causative agent of European foulbrood (EFB), a global honey bee brood disease. In order to detect putative virulence factors, we sequenced and analyzed the genomes of 14 M. plutonius strains, including two reference isolates. The isolates do not show a high diversity in genome size or number of predicted protein-encoding genes, ranging from 2...
August 20, 2018: Genes
https://www.readbyqxmd.com/read/30120972/artefactual-band-patterns-by-sds-page-of-the-vip3af-protein-in-the-presence-of-proteases-mask-the-extremely-high-stability-of-this-protein
#19
Núria Banyuls, Patricia Hernández-Martínez, Yudong Quan, Juan Ferré
Vip3 proteins are secretable proteins from Bacillus thuringiensis with important characteristics for the microbiological control of agricultural pests. The exact details of their mode of action are yet to be disclosed and the crystallographic structure is still unknown. Vip3 proteins are expressed as protoxins that have to be activated by the insect gut proteases. A previous study on the peptidase processing of Vip3Aa revealed that the protoxin produced artefactual band patterns by SDS-PAGE due to the differential stability of this protein and the peptidases to SDS and heating (Bel et al...
December 2018: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/30097439/enhancement-of-bacillus-thuringiensis-cry1ab-and-cry1fa-toxicity-to-spodoptera-frugiperda-by-domain-iii-mutations-indicates-there-are-two-limiting-steps-in-toxicity-as-defined-by-receptor-binding-and-protein-stability
#20
Isabel Gómez, Josue Ocelotl, Jorge Sánchez, Christina Lima, Erica Martins, Anayeli Rosales-Juárez, Sotero Aguilar-Medel, André Abad, Hua Dong, Rose Monnerat, Guadalupe Peña, Jie Zhang, Mark Nelson, Gusui Wu, Alejandra Bravo, Mario Soberón
Bacillus thuringiensis Cry1Ab and Cry1Fa toxins are environmentally safe insecticides that control important insect pests. Spodoptera frugiperda is an important maize pest that shows low susceptibility to Cry1A toxins, in contrast to Cry1Fa, which is highly active against this pest and is used in transgenic maize for S. frugiperda control. The β16 region from domain III of Cry1Ab has been shown to be involved in interactions with receptors such as alkaline phosphatase (ALP) or aminopeptidase (APN) in different lepidopteran insects...
October 15, 2018: Applied and Environmental Microbiology
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