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Bacillus thuringiensis receptors

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https://www.readbyqxmd.com/read/28883440/mechanism-and-dna-based-detection-of-field-evolved-resistance-to-transgenic-bt-corn-in-fall-armyworm-spodoptera-frugiperda
#1
Rahul Banerjee, James Hasler, Robert Meagher, Rodney Nagoshi, Lucas Hietala, Fangneng Huang, Kenneth Narva, Juan Luis Jurat-Fuentes
Evolution of resistance threatens sustainability of transgenic crops producing insecticidal proteins from the bacterium Bacillus thuringiensis (Bt). The fall armyworm (Spodoptera frugiperda) is a devastating pest of corn in the Western Hemisphere initially controlled by transgenic Bt corn producing the Cry1Fa insecticidal protein (event TC1507). However field-evolved resistance to TC1507 was observed in Puerto Rico in 2007 and has subsequently been reported in a number of locations in North and South America...
September 7, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28808417/down-regulation-of-aminopeptidase-n-and-abc-transporter-subfamily-g-transcripts-in-cry1ab-and-cry1ac-resistant-asian-corn-borer-ostrinia-furnacalis-lepidoptera-crambidae
#2
Tiantao Zhang, Brad S Coates, Yueqin Wang, Yidong Wang, Shuxiong Bai, Zhenying Wang, Kanglai He
The Asian corn borer (ACB), Ostrinia furnacalis (Lepidoptera: Crambidae), is a highly destructive pest of cultivated maize throughout East Asia. Bacillus thuringiensis (Bt) crystalline protein (Cry) toxins cause mortality by a mechanism involving pore formation or signal transduction following toxin binding to receptors along the midgut lumen of susceptible insects, but this mechanism and mutations therein that lead to resistance are not fully understood. In the current study, quantitative comparisons were made among midgut expressed transcripts from O...
2017: International Journal of Biological Sciences
https://www.readbyqxmd.com/read/28751263/improving-insect-control-protein-activity-for-gm-crops-a-case-study-demonstrating-that-increased-target-insect-potency-can-be-achieved-without-impacting-mammalian-safety
#3
Donna R Farmer, Thomas C Edrington, Colton R Kessenich, Cunxi Wang, Jay S Petrick
Many insect-protected crops express insecticidal crystal (Cry) proteins derived from the soil bacterium Bacillus thuringiensis (Bt), including both naturally-occurring Cry proteins and chimeric Cry proteins created through biotechnology. The Cry51Aa2 protein is a naturally-occurring Cry protein that was modified to increase its potency and expand its insect activity spectrum through amino acid sequence changes. The improved Cry51Aa2 variant, Cry51Aa2.834_16, and other developmental variants belong to the ETX_MTX2 family of proteins but share a low level of sequence similarity to other members of this family...
July 24, 2017: Regulatory Toxicology and Pharmacology: RTP
https://www.readbyqxmd.com/read/28736301/foxa-transcriptional-factor-modulates-insect-susceptibility-to-bacillus-thuringiensis-cry1ac-toxin-by-regulating-the-expression-of-toxin-receptor-abcc2-and-abcc3-genes
#4
Jianghuai Li, Yuemin Ma, Wanli Yuan, Yutao Xiao, Chenxi Liu, Jia Wang, Jianxin Peng, Rong Peng, Mario Soberón, Alejandra Bravo, Yongbo Yang, Kaiyu Liu
Cry toxins produced by Bacillus thuringiensis (Bt) are insecticidal proteins widely used in insect control. Recently, it was shown that ATP-binding cassette transporter proteins (ABC) such as ABCC2, ABCC3, ABCG1 and ABCA2 are implicated in the insecticidal action of Cry toxins as putative receptors. However, the transcriptional regulators involved in the expression of ABC transporter genes remain unknown. Sequence analysis of promoter regions of ABCC2 gene from Helicoverpa armigera and ABCC3 gene from Spodoptera litura Sl-HP cultured cells, revealed the potential participation of Forkhead box protein A (FOXA), a transcription factor that regulates the expression of genes through remodeling chromatin...
July 21, 2017: Insect Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/28729614/knockdown-of-two-cadherin-genes-confers-resistance-to-cry2a-and-cry1c-in-chilo-suppressalis
#5
Zan Zhang, Xiaolu Teng, Weihua Ma, Fei Li
Bacillus thuringiensis (Bt) Cry toxins play an important role in the management of insect pests. Resistance to Bt toxins has been reported in many pest insects but the mechanism responsible for this resistance in rice crop pests remains largely unknown. Cadherin is one of several Bt toxin receptors. At present, only one cadherin gene, CsCAD1, has been documented in the striped rice stem borer, Chilo suppressalis. We amplified a nearly full-length transcript of another C. suppressalis cadherin gene, CsCAD2, and found that it has a different expression pattern to CsCAD1...
July 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28720548/pxapn5-serves-as-a-functional-receptor-of-cry2ab-in-plutella-xylostella-l-and-its-binding-domain-analysis
#6
Zhi-Zhen Pan, Lian Xu, Bo Liu, Jing Zhang, Zheng Chen, Qing-Xi Chen, Yu-Jing Zhu
Lepidopteran midgut aminopeptidases N (APNs) are widely studied for their potential roles as one of the receptors for the Bacillus thuringiensis (Bt) crystal insecticidal toxins. In the present study, a loss of function analyses by RNAi (RNA interference) silencing of the Plutella xylostella APN5 (PxAPN5), a binding protein of Cry2Ab, were performed. The knocking down of PxAPN5 in P. xylostella larvae greatly reduced their susceptibility to Cry2Ab and led to a decrease of Cry2Ab binding to P. xylostella midgut...
July 15, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28710264/dissimilar-crystal-proteins-cry5ca1-and-cry5da1-synergistically-act-against-meloidogyne-incognita-and-delay-cry5ba-based-nematode-resistance
#7
Ce Geng, Yingying Liu, Miaomiao Li, Zhen Tang, Sajid Muhammad, Jinshui Zheng, Danfeng Wan, Donghai Peng, Lifang Ruan, Ming Sun
Cry proteins of Bacillus thuringiensis (Bt) have been successfully used as biopesticides and in transgenic crops throughout the world. However, resources against the most serious agricultural pathogens, plant root-knot nematodes, are limited. The genomes of several highly nematicidal virulent Bt strains from our laboratory have been sequenced, facilitating the identification of novel Cry proteins and other virulence factors. We identified two novel Cry proteins, Cry5Ca1 and Cry5Da1, that exhibit high toxicity against Meloidogyne incognita Using the Caenorhabditis elegans model, the two Cry5 toxins were shown to negatively affect nematode life span, fertility, and survival...
September 15, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28623231/cry6aa1-a-bacillus-thuringiensis-nematocidal-and-insecticidal-toxin-forms-pores-in-planar-lipid-bilayers-at-extremely-low-concentrations-and-without-the-need-of-proteolytic-processing
#8
COMPARATIVE STUDY
Eva Fortea, Vincent Lemieux, Léna Potvin, Vimbai Chikwana, Samantha Griffin, Timothy Hey, David McCaskill, Kenneth Narva, Sek Yee Tan, Xiaoping Xu, Vincent Vachon, Jean-Louis Schwartz
Cry6Aa1 is a Bacillus thuringiensis (Bt) toxin active against nematodes and corn rootworm insects. Its 3D molecular structure, which has been recently elucidated, is unique among those known for other Bt toxins. Typical three-domain Bt toxins permeabilize receptor-free planar lipid bilayers (PLBs) by forming pores at doses in the 1-50 μg/ml range. Solubilization and proteolytic activation are necessary steps for PLB permeabilization. In contrast to other Bt toxins, Cry6Aa1 formed pores in receptor-free bilayers at doses as low as 200 pg/ml in a wide range of pH (5...
August 11, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28608568/the-macrophage-activation-induced-by-bacillus-thuringiensis-cry1ac-protoxin-involves-erk1-2-and-p38-pathways-and-the-interaction-with-cell-surface-hsp70
#9
Néstor Rubio-Infante, Damaris Ilhuicatzi-Alvarado, Marilu Torres-Martínez, Juan Pablo Reyes-Grajeda, Raúl Nava-Acosta, Edith González-González, Leticia Moreno-Fierros
Here, we aimed to further characterize the mechanisms involved in protoxin (p) Cry1Ac-induced macrophage activation. We demonstrated that pCry1Ac induces MAPK ERK1/2, p38 and JNK phosphorylation in RAW264.7 macrophages. Because MAPK activation is mainly triggered via ligand-receptor interactions, we focused on the identification of potential pCry1Ac-receptor proteins. Flow cytometry and confocal analysis showed specific saturable pCry1Ac-binding to the macrophage surface and evidenced its internalization via the clathrin-pathway...
June 13, 2017: Journal of Cellular Biochemistry
https://www.readbyqxmd.com/read/28587836/functional-characterization-of-aedes-aegypti-alkaline-phosphatase-alp1-involved-in-the-toxicity-of-cry-toxins-from-bacillus-thuringiensis-subsp-israelensis-and-jegathesan
#10
Jianwu Chen, Karly Aimanova, Sarjeet S Gill
Presently three major groups of proteins from Aedes aegypti, cadherin, alkaline phosphatases (ALP) and aminopeptidases N (APN), have been identified as Cry11Aa toxin receptors. To further characterize their role on toxicity, transgenic mosquitoes with silenced Aedes cadherin expression were previously generated and the role of cadherin in mediating the toxicity of four different mosquitocidal toxins (Cry11Aa, Cry11Ba, Cry4Aa and Cry4Ba) was demonstrated. Here, we investigated the role of another reported Cry11Aa receptor, ALP1...
June 3, 2017: Peptides
https://www.readbyqxmd.com/read/28416297/cry-toxin-specificities-of-insect-abcc-transporters-closely-related-to-lepidopteran-abcc2-transporters
#11
Haruka Endo, Shiho Tanaka, Kazuhiro Imamura, Satomi Adegawa, Shingo Kikuta, Ryoichi Sato
In this study, we examined insect and human ABCC transporters closely related to the lepidopteran ABC transporter C2 (ABCC2), a powerful receptor for the Bacillus thuringiensis Cry toxin, for their responses to various Cry toxins. ABCC2 and the lepidopteran ABC transporter C3 (ABCC3) conferred cultured cells with susceptibility to a lepidopteran-specific Cry1Aa toxin but not to lepidopteran-specific Cry1Ca and Cry1Da. One coleopteran ABCC transporter specifically responded to a coleopteran-specific Cry8Ca toxin...
April 14, 2017: Peptides
https://www.readbyqxmd.com/read/28389549/holotrichia-oblita-midgut-proteins-that-bind-to-bacillus-thuringiensis-cry8-like-toxin-and-assembly-of-the-h-oblita-midgut-tissue-transcriptome
#12
Jian Jiang, Ying Huang, Changlong Shu, Mario Soberón, Alejandra Bravo, Chunqing Liu, Fuping Song, Jinsheng Lai, Jie Zhang
The Bacillus thuringiensis strain HBF-18 (CGMCC 2070), containing two cry genes (cry8-like and cry8Ga), is toxic to Holotrichia oblita larvae. Both Cry8-like and Cry8Ga proteins are active against this insect pest, and Cry8-like is more toxic. To analyze the characteristics of the binding of Cry8-like and Cry8Ga proteins to brush border membrane vesicles (BBMVs) in H. oblita larvae, binding assays were conducted with a fluorescent DyLight488-labeled Cry8-like toxin. The results of saturation binding assays demonstrated that Cry8-like bound specifically to binding sites on BBMVs from H...
June 15, 2017: Applied and Environmental Microbiology
https://www.readbyqxmd.com/read/28364809/influence-of-ephestia-kuehniella-stage-larvae-on-the-potency-of-bacillus-thuringiensis-cry1aa-delta-endotoxin
#13
Nouha Abdelmalek, Sameh Sellami, Mireille Kallassy-Awad, Molka Feki Tounsi, Abdelkrim Mebarkia, Slim Tounsi, Souad Rouis
The economically important crop pest Ephestia kuehniella was tested at two stages of larval development for susceptibility to Bacillus thuringiensis Cry1Aa toxin. Bioassays showed that toxicity decreased during the development of larvae stage. In fact, Cry1Aa toxins from BNS3-Cry(-) (pHT-cry1Aa) showed low toxicity against the first-instar larvae (L1) with a LC50 value of about 421.02μg/g of diet and was not toxic against the fifth-instar (L5), comparing to the BLB1 toxins used as positive control which represent a LC50 value of about 56...
April 2017: Pesticide Biochemistry and Physiology
https://www.readbyqxmd.com/read/28358336/patterns-of-gene-expression-in-western-corn-rootworm-diabrotica-virgifera-virgifera-neonates-challenged-with-cry34ab1-cry35ab1-and-cry34-35ab1-based-on-next-generation-sequencing
#14
Haichuan Wang, Seong-Il Eyun, Kanika Arora, Sek Yee Tan, Premchand Gandra, Etsuko Moriyama, Chitvan Khajuria, Jessica Jurzenski, Huarong Li, Maia Donahue, Ken Narva, Blair Siegfried
With Next Generation Sequencing technologies, high-throughput RNA sequencing (RNAseq) was conducted to examine gene expression in neonates of Diabrotica virgifera virgifera (LeConte) (Western Corn Rootworm, WCR) challenged with individual proteins of the binary Bacillus thuringiensis insecticidal proteins, Cry34Ab1 and Cry35Ab1, and the combination of Cry34/Cry35Ab1, which together are active against rootworm larvae. Integrated results of three different statistical comparisons identified 114 and 1300 differentially expressed transcripts (DETs) in the Cry34Ab1 and Cry34/35Ab1 treatment, respectively, as compared to the control...
March 30, 2017: Toxins
https://www.readbyqxmd.com/read/28341807/the-human-cancer-cell-active-toxin-cry41aa-from-bacillus-thuringiensis-acts-like-its-insecticidal-counterparts
#15
COMPARATIVE STUDY
Vidisha Krishnan, Barbara Domanska, Alicia Elhigazi, Fatai Afolabi, Michelle J West, Neil Crickmore
Understanding how certain protein toxins from the normally insecticidal bacterium Bacillus thuringiensis (Bt) target human cell lines has implications for both the risk assessment of products containing these toxins and potentially for cancer therapy. This understanding requires knowledge of whether the human cell active toxins work by the same mechanism as their insecticidal counterparts or by alternative ones. The Bt Cry41Aa (also known as Parasporin3) toxin is structurally related to the toxins synthesised by commercially produced transgenic insect-resistant plants, with the notable exception of an additional C-terminal β-trefoil ricin domain...
April 28, 2017: Biochemical Journal
https://www.readbyqxmd.com/read/28327568/aminopeptidase-n1-is-involved-in-bacillus-thuringiensis-cry1ac-toxicity-in-the-beet-armyworm-spodoptera-exigua
#16
Lin Qiu, Songhe Cui, Lang Liu, Boyao Zhang, Weihua Ma, Xiaoping Wang, Chaoliang Lei, Lizhen Chen
Understanding how insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) interact with their hosts is crucial to fully explain the molecular bases of Bt specificity and insecticidal activity. Previous studies support ATP binding cassette transporters (ABCC2/3) and one cadherin-like protein are Cry1Ac functional receptors in the beet armyworm (Spodoptera exigua). In this study, a combined one-dimensional gel electrophoresis and immunoblotting approach identified aminopeptidase N (APNs) as putative Cry1Ac binding proteins in the midgut brush border membrane of S...
March 22, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28274717/rna-interference-knockdown-of-aminopeptidase-n-genes-decrease-the-susceptibility-of-chilo-suppressalis-larvae-to-cry1ab-cry1ac-and-cry1ca-expressing-transgenic-rice
#17
Lin Qiu, Jinxing Fan, Boyao Zhang, Lang Liu, Xiaoping Wang, Chaoliang Lei, Yongjun Lin, Weihua Ma
Transgenic rice expressing Bacillus thuringiensis (Bt) Cry toxins are resistant to lepidopteran pests, such as Chilo suppressalis, a major insect pest of rice in Asia. Understanding how these toxins interact with their hosts is crucial to understanding their insecticidal action. In this study, knockdown of two aminopeptidase N genes (APN1 and APN2) by RNA interference resulted in decreased susceptibility of C. suppressalis larvae to the Bt rice varieties TT51 (Cry1Ab and Cry1Ac fusion genes) and T1C-19 (Cry1Ca), but not T2A-1 (Cry2Aa)...
March 6, 2017: Journal of Invertebrate Pathology
https://www.readbyqxmd.com/read/28223048/vegetative-insecticidal-protein-of-bacillus-thuringiensis-blb459-and-its-efficiency-against-lepidoptera
#18
Hanen Boukedi, Saoussen Ben Khedher, Rania Hadhri, Samir Jaoua, Slim Tounsi, Lobna Abdelkefi-Mesrati
Bacillus thuringiensis strain BLB459 supernatant showed a promising activity against Lepidopteran pests with extremely damages in the larvae midgut. Investigations of the genes that encode secreted toxin demonstrated that this strain harbored a vip3-type gene named vip3(459). Based on its original nucleotide and amino acid sequences, this gene was cloned into pET-14b vector and overexpressed in Escherichia coli. The expressed protein was purified and tested against different insects and interestingly the novel toxin demonstrated a remarkable activity against the stored products pest Ephestia kuehniella and the polyphagous insects Spodoptera littoralis and Agrotis segetum...
April 2017: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/28186125/responses-of-the-cutworm-spodoptera-litura-lepidoptera-noctuidae-to-two-bt-corn-hybrids-expressing-cry1ab
#19
Shu Yinghua, Du Yan, Chen Jin, Wei Jiaxi, Wang Jianwu
To examine the responses of the secondary lepidopteran pest Spodoptera litura to two Bacillus thuringiensis (Bt) corn hybrids [5422Bt1 (Event Bt11), 5422CBCL (MON810)] expressing Cry1Ab, larval bioassays with Cry1Ab toxin, corn leaves or kernels and bagging on corn plants were conducted. The results showed that larvae displayed a similar performance when fed kernels, but not leaves of 5422Bt1, 5422CBCL and their near-isogenic non-Bt corn (5422). Significantly higher Cry1Ab amounts were detected in larvae fed leaves than kernels of both Bt hybrids, with different molecular weights of protein band in plants (72 and 90 kDa for 5422Bt1 and 5422CBCL, respectively), gut contents (65 kDa), feces (50 kDa), which indicated that larvae had lower ingestion, higher degradation and excretion of Cry1Ab when fed kernels not leaves of both Bt hybrids...
February 10, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28093209/combinatorial-effect-of-bacillus-amyloliquefaciens-ag1-biosurfactant-and-bacillus-thuringiensis-vip3aa16-toxin-on-spodoptera-littoralis-larvae
#20
Saoussen Ben Khedher, Hanen Boukedi, Mariam Dammak, Olfa Kilani-Feki, Tahya Sellami-Boudawara, Lobna Abdelkefi-Mesrati, Slim Tounsi
Spodoptera littoralis, one of the most serious and destructive agricultural pests in the world, is very susceptible to Vip3 toxin. In order to develop a new efficient bioinsecticide and to prevent the development of resistance by the target pest, insecticidal activity of biosurfactant produced by Bacillus amyloliquefaciens AG1 was evaluated against S. littoralis. Bioassays revealed the susceptibility of the first instar larvae of this pest to AG1 biosurfactant with an LC50 of 245ng/cm(2). Moreover, the histopathology examination of the larval midgut treated by AG1 biosurfactant showed vacuolization, necrosis and disintegration of the basement membrane...
March 2017: Journal of Invertebrate Pathology
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