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Bacillus thuringiensis receptors

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https://www.readbyqxmd.com/read/27929397/a-p-glycoprotein-is-linked-to-resistance-to-the-bacillus-thuringiensis-cry3aa-toxin-in-a-leaf-beetle
#1
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
#2
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
#3
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...
November 22, 2016: 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
#4
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...
November 23, 2016: 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
#5
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)...
November 17, 2016: 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
#6
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-explain-resistance-in-insects
#7
Shiho Tanaka, Haruka Endo, Satomi Adegawa, Shingo Kikuta, Ryoichi Sato
Bacillus thuringiensis produces Cry toxins, which are used as insecticides in sprays or 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 to Xenopus oocytes, and the Cry1Aa-dependent cation selective pore-formation activities of these receptors were analyzed using a two-electrode voltage clamp...
November 4, 2016: FEBS Journal
https://www.readbyqxmd.com/read/27769815/parasporins-1-and-2-their-structure-and-activity
#8
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...
October 18, 2016: Journal of Invertebrate Pathology
https://www.readbyqxmd.com/read/27762484/-non-haemolytic-enterotoxin-nhe-of-bacillus-cereus-induces-apoptosis-in-vero-cells
#9
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-haemolytic 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
#10
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
#11
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.
September 20, 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
#12
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
#13
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
#14
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
https://www.readbyqxmd.com/read/27436734/bacillus-thuringiensis-toxin-resistance-mechanisms-among-lepidoptera-progress-on-genomic-approaches-to-uncover-causal-mutations-in-the-european-corn-borer-ostrinia-nubilalis
#15
REVIEW
Brad S Coates
Transgenic plants that express Bacillus thuringiensis (Bt) crystal (Cry) protein toxins (Bt crops) effectively control feeding by the European corn borer, Ostrinia nubilalis, although documented resistance evolution among a number of species in both the laboratory and field has heightened concerns about the durability of this technology. Research has provided major insights into the mutations that alter Bt toxin binding receptor structure and function within the midgut of Lepidoptera that directly impacts the efficacy of Bt toxins, and potentially leads to the evolution of resistance to Bt crops in the field...
June 2016: Current Opinion in Insect Science
https://www.readbyqxmd.com/read/27418233/receptors-are-affected-by-selection-with-each-bacillus-thuringiensis-israelensis-cry-toxin-but-not-with-the-full-bti-mixture-in-aedes-aegypti
#16
Renaud Stalinski, Frederic Laporte, Guillaume Tetreau, Laurence Després
Bacillus thuringiensis israelensis (Bti) toxins are increasingly used for mosquito control, but little is known about the precise mode of action of each of these toxins, and how they interact to kill mosquito larvae. By using RNA sequencing, we investigated change in gene transcription level and polymorphism variations associated with resistance to each Bti Cry toxin and to the full Bti toxin mixture in the dengue vector Aedes aegypti. The up-regulation of genes related to chitin metabolism in all selected strain suggests a generalist, non-toxin-specific response to Bti selection in Aedes aegypti...
October 2016: Infection, Genetics and Evolution
https://www.readbyqxmd.com/read/27343383/functional-validation-of-cadherin-as-a-receptor-of-bt-toxin-cry1ac-in-helicoverpa-armigera-utilizing-the-crispr-cas9-system
#17
Jing Wang, Haonan Zhang, Huidong Wang, Shan Zhao, Yayun Zuo, Yihua Yang, Yidong Wu
Cadherins have been identified as receptors of Bacillus thuringiensis (Bt) Cry1A toxins in several lepidopteran insects including the cotton bollworm, Helicoverpa armigera. Disruption of the cadherin gene HaCad has been genetically linked to resistance to Bt toxin Cry1Ac in H. armigera. By using the CRISPR/Cas9 genome editing system (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated protein 9), HaCad from the Cry1Ac-susceptible SCD strain of H. armigera was successfully knocked out...
September 2016: Insect Biochemistry and Molecular Biology
https://www.readbyqxmd.com/read/27333791/sequencing-de-novo-assembly-and-annotation-of-a-pink-bollworm-larval-midgut-transcriptome
#18
Erica E Tassone, Gina Zastrow-Hayes, John Mathis, Mark E Nelson, Gusui Wu, J Lindsey Flexner, Yves Carrière, Bruce E Tabashnik, Jeffrey A Fabrick
BACKGROUND: The pink bollworm Pectinophora gossypiella (Saunders) (Lepidoptera: Gelechiidae) is one of the world's most important pests of cotton. Insecticide sprays and transgenic cotton producing toxins of the bacterium Bacillus thuringiensis (Bt) are currently used to manage this pest. Bt toxins kill susceptible insects by specifically binding to and destroying midgut cells, but they are not toxic to most other organisms. Pink bollworm is useful as a model for understanding insect responses to Bt toxins, yet advances in understanding at the molecular level have been limited because basic genomic information is lacking for this cosmopolitan pest...
2016: GigaScience
https://www.readbyqxmd.com/read/27311897/toxicity-of-bacillus-thuringiensis-l-cry-proteins-against-summer-fruit-tortrix-adoxophyes-orana-fischer-von-r%C3%A3-sslerstamm
#19
Jelena Radosavljevic, Samir Naimov
The activity of seven Cry1, one Cry9 and one hybrid Cry1 protoxins against neonate larvae of summer fruit tortrix (Adoxophyes orana - Fischer von Rösslerstamm) has been investigated. Cry1Ia is identified as the most toxic protein, followed by Cry1Aa and Cry1Ac. Cry1Ca, Cry1Cb, Cry1Da and Cry1Fa were less active, while SN19 (Cry1 hybrid protein with domain composition 1Ba/1Ia/1Ba) and Cry9Aa exhibited negligible toxicity against A. orana. In vitro trypsin-activated Cry1Ac is still less active than Cry1Ia protoxin, suggesting that toxicity of Cry1Ia is most probably due to more complex differences in further downstream processing, toxin-receptor interactions and pore formation in A...
July 2016: Journal of Invertebrate Pathology
https://www.readbyqxmd.com/read/27235983/the-sequence-structural-and-functional-diversity-within-a-protein-family-and-implications-for-specificity-and-safety-the-case-for-etx_mtx2-insecticidal-proteins
#20
William J Moar, Adam J Evans, Colton R Kessenich, James A Baum, David J Bowen, Thomas C Edrington, Jeffrey A Haas, Jean-Louis K Kouadio, James K Roberts, Andre Silvanovich, Yong Yin, Brian E Weiner, Kevin C Glenn, Matthew L Odegaard
The need for sustainable insect pest control is driving the investigation and discovery of insecticidal proteins outside of the typical 3- domain Cry protein family from Bacillus thuringiensis (Bt). Examples include Cry35 and Cry51 that belong to protein families (Toxin_10, ETX_MTX2) sharing a common β-pore forming structure and function with known mammalian toxins such as epsilon toxin (ETX). Although β-pore forming proteins are related to mammalian toxins, there are key differences in sequence and structure that lead to organism specificity that is useful in the weight-of-evidence approach for safety assessment...
May 25, 2016: Journal of Invertebrate Pathology
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