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Bacillus thuringiensis receptors

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https://www.readbyqxmd.com/read/28327568/aminopeptidase-n1-is-involved-in-bacillus-thuringiensis-cry1ac-toxicity-in-the-beet-armyworm-spodoptera-exigua
#1
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
#2
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
#3
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...
February 20, 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
#4
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
#5
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
https://www.readbyqxmd.com/read/28067269/proteomic-analysis-of-cry2aa-binding-proteins-and-their-receptor-function-in-spodoptera-exigua
#6
Lin Qiu, Boyao Zhang, Lang Liu, Weihua Ma, Xiaoping Wang, Chaoliang Lei, Lizhen Chen
The bacterium Bacillus thuringiensis produces Crystal (Cry) proteins that are toxic to a diverse range of insects. Transgenic crops that produce Bt Cry proteins are grown worldwide because of their improved resistance to insect pests. Although Bt "pyramid" cotton that produces both Cry1A and Cry2A is predicted to be more resistant to several lepidopteran pests, including Spodoptera exigua, than plants that produce Cry1Ac alone, the mechanisms responsible for the toxicity of Cry2Aa in S. exigua are not well understood...
January 9, 2017: Scientific Reports
https://www.readbyqxmd.com/read/27929397/a-p-glycoprotein-is-linked-to-resistance-to-the-bacillus-thuringiensis-cry3aa-toxin-in-a-leaf-beetle
#7
Yannick Pauchet, Anne Bretschneider, Sylvie Augustin, David G Heckel
Chrysomela tremula is a polyvoltine oligophagous leaf beetle responsible for massive attacks on poplar trees. This beetle is an important model for understanding mechanisms of resistance to Bacillus thuringiensis (Bt) insecticidal toxins, because a resistant C. tremula strain has been found that can survive and reproduce on transgenic poplar trees expressing high levels of the Cry3Aa Bt toxin. Resistance to Cry3Aa in this strain is recessive and is controlled by a single autosomal locus. We used a larval midgut transcriptome for C...
December 5, 2016: Toxins
https://www.readbyqxmd.com/read/27918112/validation-of-adam10-metalloprotease-as-a-bacillus-thuringiensis-cry3aa-toxin-functional-receptor-in-colorado-potato-beetle-leptinotarsa-decemlineata
#8
V M Ruiz-Arroyo, I García-Robles, C Ochoa-Campuzano, G A Goig, E Zaitseva, G Baaken, A C Martínez-Ramírez, C Rausell, M D Real
Bacillus thuringiensis parasporal crystal proteins (Cry proteins) are insecticidal pore-forming toxins that bind to specific receptor molecules on the brush border membrane of susceptible insect midgut cells to exert their toxic action. In the Colorado potato beetle (CPB), a coleopteran pest, we previously proposed that interaction of Cry3Aa toxin with a CPB ADAM10 metalloprotease is an essential part of the mode of action of this toxin. Here, we annotated the gene sequence encoding an ADAM10 metalloprotease protein (CPB-ADAM10) in the CPB genome sequencing project, and using RNA interference gene silencing we demonstrated that CPB-ADAM10 is a Cry3Aa toxin functional receptor in CPB...
December 5, 2016: Insect Molecular Biology
https://www.readbyqxmd.com/read/27888109/ephestia-kuehniella-tolerance-to-bacillus-thuringiensis-cry1aa-is-associated-with-reduced-oligomer-formation
#9
Maissa Chakroun, Sameh Sellami, Juan Ferré, Slim Tounsi, Souad Rouis
The basis of the different susceptibility of Ephestia kuehniella to the Cry1Aa and Cry1Ac δ-endotoxins from Bacillus thuringiensis kurstaki BNS3 was studied. Both toxins bound specifically to the BBMV of E. kuehniella. The result of the ligand blot showed that Cry1Ac bound to three putative receptors of about 100, 65 and 80 kDa and Cry1Aa interacted only with a 100 kDa protein. Pronase digestion of the BBMV-bound toxins was used to analyze the toxin insertion. Both toxins inserted into the BBMV as monomers however, a 14 kDa peptide of α4-α5 which correspond to the oligomeric form of this peptide was detected in case of Cry1Ac only...
January 22, 2017: Biochemical and Biophysical Research Communications
https://www.readbyqxmd.com/read/27888075/the-domain-ii-loops-of-bacillus-thuringiensis-cry1aa-form-an-overlapping-interaction-site-for-two-bombyx-mori-larvae-functional-receptors-abc-transporter-c2-and-cadherin-like-receptor
#10
Satomi Adegawa, Yui Nakama, Haruka Endo, Naoki Shinkawa, Shingo Kikuta, Ryoichi Sato
Information about the receptor-interaction region of Cry toxins, insecticidal proteins produced by Bacillus thuringiensis, is needed to elucidate the mode of action of Cry toxins and improve their toxicity through protein engineering. We analyzed the interaction sites on Cry1Aa with ABC transporter C2 (ABCC2), one of the most important Cry1A toxin receptors. A competitive binding assay revealed that the Bombyx mori ABCC2 (BmABCC2) Cry1A binding site was the same as the BtR175 binding site, suggesting that the loop region of Cry1Aa domain II is a binding site...
February 2017: Biochimica et Biophysica Acta
https://www.readbyqxmd.com/read/27867074/toxicity-of-cry1a-toxins-from-bacillus-thuringiensis-to-cf1-cells-does-not-involve-activation-of-adenylate-cyclase-pka-signaling-pathway
#11
Leivi Portugal, Carlos Muñóz-Garay, Diana L Martínez de Castro, Mario Soberón, Alejandra Bravo
Bacillus thuringiensis (Bt) bacteria produce Cry toxins that are able to kill insect pests. Different models explaining the mode of action of these toxins have been proposed. The pore formation model proposes that the toxin creates pores in the membrane of the larval midgut cells after interaction with different receptors such as cadherin, aminopeptidase N and alkaline phosphatase and that this pore formation activity is responsible for the toxicity of these proteins. The alternative model proposes that interaction with cadherin receptor triggers an intracellular cascade response involving protein G, adenylate cyclase (AC) and protein kinase A (PKA)...
January 2017: Insect Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/27823898/rnai-in-the-striped-stem-borer-chilo-suppressalis-establishes-a-functional-role-for-aminopeptidase-n-in-cry1ab-intoxication
#12
X Y Wang, L X Du, C X Liu, L Gong, L Z Han, Y F Peng
The striped stem borer, Chilo suppressalis, is a major target pest of transgenic rice expressing the Cry1Ab protein from the bacterium Bacillus thuringiensis (Bt) in China. Evolution of resistance in this pest is a major threat to the durability of Bt rice. Since Bt exerts its activity through binding to specific receptors in the midgut of target insects, identification of functional Cry1Ab receptors in the midgut of C. suppressalis larvae is crucial to evaluate potential resistance mechanisms and develop effective strategies for delaying insect resistance...
November 4, 2016: Journal of Invertebrate Pathology
https://www.readbyqxmd.com/read/27813251/functional-characterization-of-bacillus-thuringiensis-cry-toxin-receptors-explains-resistance-in-insects
#13
Shiho Tanaka, Haruka Endo, Satomi Adegawa, Shingo Kikuta, Ryoichi Sato
Bacillus thuringiensis produces Cry toxins, which are used as insecticides in sprays and in transgenic crops. However, little is known about the function of Cry toxin receptors and the mechanisms that determine their binding specificity and activity. In this study, the cRNAs of Bombyx mori ABC transporter C2 (BmABCC2), the toxin-binding region of cadherin-like receptor (BtR175-TBR), or aminopeptidase N1 (BmAPN1) were injected into Xenopus oocytes, and the Cry1Aa-dependent cation-selective pore formation activities of these receptors were analyzed using a two-electrode voltage clamp...
December 2016: FEBS Journal
https://www.readbyqxmd.com/read/27769815/parasporins-1-and-2-their-structure-and-activity
#14
REVIEW
Toshihiko Akiba, Shiro Okumura
Parasporins are novel protein toxins preferentially cytotoxic against human cancer cells. They are obtained from parasporal inclusions of Bacillus thuringiensis and, accordingly, are considered congeners of the insecticidal Cry toxins. Two types of parasporins have been identified: the three-domain Cry toxin type and the β-pore-forming-toxin (β-PFT) type. Crystal structures of representative members of the two types, PS1Aa1 and PS2Aa1, have been determined and compared with those of well-studied toxins. PS1Aa1 has a typical architecture characteristic of the three-domain insecticidal Cry toxins, though it is cleaved into two polypeptides...
January 2017: Journal of Invertebrate Pathology
https://www.readbyqxmd.com/read/27762484/non-hemolytic-enterotoxin-of-bacillus-cereus-induces-apoptosis-in-vero-cells
#15
Xiaoye Liu, Shuangyang Ding, Peijie Shi, Richard Dietrich, Erwin Märtlbauer, Kui Zhu
Bacillus cereus is an opportunistic pathogen that often causes foodborne infectious diseases and food poisoning. Non-hemolytic enterotoxin (Nhe) is the major toxin found in almost all enteropathogenic B. cereus and B. thuringiensis isolates. However, little is known about the cellular response after Nhe triggered pore formation on cell membrane. Here, we demonstrate that Nhe induced cell cycle arrest at G0 /G1 phase and provoked apoptosis in Vero cells, most likely associated with mitogen-activated protein kinase (MAPK) and death receptor pathways...
October 20, 2016: Cellular Microbiology
https://www.readbyqxmd.com/read/27713207/identification-of-a-bacillus-thuringiensis-surface-layer-protein-with-cytotoxic-activity-against-mda-mb-231-breast-cancer-cells
#16
Viviana P Rubio, Alejandra Bravo, Jorge Olmos
In this work we isolated a Surface-Layer-Protein (SLP) from a Bacillus thuringiensis (Bt) strain to evaluate it cytotoxic effects against MDA-MB-231 human breast cancer cells. AP11 was selected from a group of Bt strains using SLP oligonucleotides developed from Bacillus conserved regions. AP11 strain was grown in Luria Bertani (LB) medium until late exponential phase; an 86 kDa protein was extracted using 5 M LiCl and identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS). It corresponded to a multispecies S-layer protein highly similar to previously described SLP in B...
October 6, 2016: Journal of Microbiology and Biotechnology
https://www.readbyqxmd.com/read/27662801/unshared-binding-sites-for-bacillus-thuringiensis-cry3aa-and-cry3ca-proteins-in-the-weevil-cylas-puncticollis-brentidae
#17
Patricia Hernández-Martínez, Natalia Mara Vera-Velasco, Baltasar Escriche
Bacillus thuringiensis Cry3Aa and Cry3Ca proteins have been reported to be toxic against the African sweetpotato pest Cylas puncticollis. In the present work, the binding sites of these proteins in C. puncticollis brush border vesicles suggest the occurrence of different binding sites, but only one of them is shared. Our results suggest that pest resistance mediated by alteration of the shared Cry-receptor binding site might not render both Cry proteins ineffective.
November 2016: Toxicon: Official Journal of the International Society on Toxinology
https://www.readbyqxmd.com/read/27628909/effects-and-mechanisms-of-bacillus-thuringiensis-crystal-toxins-for-mosquito-larvae
#18
Qi Zhang, Gang Hua, Michael J Adang
Bacillus thuringiensis is a gram-positive aerobic bacterium that produces insecticidal crystalline inclusions during sporulation phases of the mother cell. The virulence factor, known as parasporal crystals, is composed of Cry and Cyt toxins. Cry toxins display a common three-domain topology. Cry toxins exert intoxication through toxin activation, receptor binding and pore formation in suitable larval gut environment. The mosquitocidal toxins, Bt subsp. israelensis (Bti) and was found highly active against mosquito larvae and are widely used in pesticide market for vector control...
September 15, 2016: Insect Science
https://www.readbyqxmd.com/read/27456115/three-toxins-two-receptors-one-mechanism-mode-of-action-of-cry1a-toxins-from-bacillus-thuringiensis-in-heliothis-virescens
#19
Anne Bretschneider, David G Heckel, Yannick Pauchet
Insecticidal crystal (Cry) proteins from Bacillus thuringiensis (Bt) are highly active against Lepidoptera. However, field-evolved resistance to Bt toxins is on the rise. The 12-cadherin domain protein HevCaLP and the ABC transporter HevABCC2 are both genetically linked to Cry toxin resistance in Heliothis virescens. We investigated their interaction using stably expressing non-lytic clonal Sf9 cell lines expressing either protein or both together. Untransfected Sf9 cells are innately sensitive to Cry1Ca toxin, but not to Cry1A toxins; and quantitative PCR revealed negligible expression of genes involved in Cry1A toxicity such as cadherin, ABCC2, alkaline phosphatase (ALP) and aminopeptidase N (APN)...
September 2016: Insect Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/27452121/cry1ab-expressing-rice-did-not-influence-expression-of-fecundity-related-genes-in-the-wolf-spider-pardosa-pseudoannulata
#20
Juan Wang, Yuan-De Peng, Chao He, Bao-Yang Wei, Yun-Shan Liang, Hui-Lin Yang, Zhi Wang, David Stanley, Qi-Sheng Song
The impact of Bacillus thuringiensis (Bt) toxin proteins on non-target predatory arthropods is not well understood at the cellular and molecular levels. Here, we investigated the potential effects of Cry1Ab expressing rice on fecundity of the wolf spider, Pardosa pseudoannulata, and some of the underlying molecular mechanisms. The results indicated that brown planthoppers (BPHs) reared on Cry1Ab-expressing rice accumulated the Cry toxin and that reproductive parameters (pre-oviposition period, post-oviposition stage, number of eggs, and egg hatching rate) of the spiders that consumed BPHs reared on Bt rice were not different from those that consumed BPHs reared on the non-Bt control rice...
October 30, 2016: Gene
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