Interaction of <scp>L</scp>ysinibacillus sphaericus Cry48Aa/Cry49Aa toxin with midgut brush‐border membrane fractions from <scp>C</scp>ulex quinquefasciatus larvae

Guo, Qianjin; Hu, Xiaomin; Cai, Quan; Yan, Jianping; Yuan, Zhiming

doi:10.1111/imb.12209

Cited by 13 publications

(31 citation statements)

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“…Recently it was shown that both subunits display the ability to bind to the C. quinquefasciatus larval midgut (Guo et al, 2016). In this context, the major goal of the present study was to identify potential ligands for Cry48Aa/Cry49Aa in the midgut of C. quinquefasciatus larvae and contribute to the understanding of the mode of action of this mosquitocidal toxin.…”

Section: Introductionmentioning

confidence: 96%

“…Cry48Aa/Cry49Aa is considered a new binary toxin produced by L. sphaericus since neither the Cry48Aa nor Cry49Aa component shows toxicity to larvae alone (Jones et al, 2007). They can act in synergy forming the complex Cry48Aa/Cry49Aa through the N-terminal portion of the Cry49Aa subunit (Guo et al, 2016). These toxins have comparable toxicity to Bin against C. quinquefasciatus, and remain active to Bin-resistant larvae, when both Cry toxins are produced as recombinant proteins and are administered in equimolar ratios (Jones et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Cry49Aa is part of the group Bin-toxin-like proteins (Toxin-10 family) with about 30% identity to both subunits of the Bin toxin from L. sphaericus, in addition to comparable identity to Cry36 (34%) and Cry35 (20%) produced by B. thuringiensis strains (Berry, 2012;Jones et al, 2007). The initial steps of the mode of action of Cry48Aa and Cry49Aa are similar to that of the Bin toxin comprising ingestion of crystals, solubilization under alkaline pH and proteolytic activation of protoxins into toxins (Jones et al, 2008), interaction with midgut (de Melo et al, 2009;Guo et al, 2016) followed by cytopathological effects which appear similar to those produced by a synergistic mixture of Cry-like and Bin-like toxins (de Melo et al, 2009). However, the identity of ligands and receptors in the larval midgut that underlie toxic action and larval mortality is still unknown.…”

Section: Introductionmentioning

confidence: 99%

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Identification of Cry48Aa/Cry49Aa toxin ligands in the midgut of Culex quinquefasciatus larvae

Rezende

Romão

Batista

et al. 2017

Insect Biochemistry and Molecular Biology

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A binary mosquitocidal toxin composed of a three-domain Cry-like toxin (Cry48Aa) and a binary-like toxin (Cry49Aa) was identified in Lysinibacillus sphaericus. Cry48Aa/Cry49Aa has action on Culex quinquefasciatus larvae, in particular, to those that are resistant to the Bin Binary toxin, which is the major insecticidal factor from L. sphaericus-based biolarvicides, indicating that Cry48Aa/Cry49Aa interacts with distinct target sites in the midgut and can overcome Bin toxin resistance. This study aimed to identify Cry48Aa/Cry49Aa ligands in C. quinquefasciatus midgut through binding assays and mass spectrometry. Several proteins, mostly from 50 to 120 kDa, bound to the Cry48Aa/Cry49Aa toxin were revealed by toxin overlay and pull-down assays. These proteins were identified against the C. quinquefasciatus genome and after analysis a set of 49 proteins were selected which includes midgut bound proteins such as aminopeptidases, amylases, alkaline phosphatases in addition to molecules from other classes that can be potentially involved in this toxin's mode of action. Among these, some proteins are orthologs of Cry receptors previously identified in mosquito larvae, as candidate receptors for Cry48Aa/Cry49Aa toxin. Further investigation is needed to evaluate the specificity of their interactions and their possible role as receptors.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Identification of Cry48Aa/Cry49Aa toxin ligands in the midgut of Culex quinquefasciatus larvae

Rezende

Romão

Batista

et al. 2017

Insect Biochemistry and Molecular Biology

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“…In this context, the L. sphaericus IAB59 strain was thus found to be toxic to Bin-resistant larvae [21, 30] and able to produce the Bin toxin as well as Cry48Aa/Cry49Aa, another binary toxin responsible for the larvicidal effect against those larvae [31, 32]. Previous studies have indicated that the Cry48Aa/Cry49Aa toxin was able to interact with receptors from the midgut of susceptible [33] and also with Bin resistant larvae lacking the Cqm1 receptor [34]. Specific receptors involved in this interaction with Cry48Aa/Cry49Aa are being studied and potential candidates have been recently tentatively identified [35].…”

Section: Introductionmentioning

confidence: 99%

A differential transcriptional profile by Culex quinquefasciatus larvae resistant to Lysinibacillus sphaericus IAB59 highlights genes and pathways associated with the resistance phenotype

Rezende

Wallau

et al. 2019

Parasites Vectors

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Background The study of the mechanisms by which larvae of the Culex quinquefasciatus mosquito survive exposure to the entomopathogen Lysinibacillus sphaericus has benefited substantially from the generation of laboratory-selected colonies resistant to this bacterium. One such colony, RIAB59, was selected after regular long-term exposure of larvae to the L. sphaericus IAB59 strain. This strain is characterized by its ability to produce the well known Binary (Bin) toxin, and the recently characterized Cry48Aa/Cry49Aa toxin, able to kill Bin-resistant larvae. Resistance to Bin is associated with the depletion of its receptor, Cqm1 α-glucosidase, from the larvae midgut. This study aimed to identify novel molecules and pathways associated with survival of the RIAB59 larvae and the resistance phenotype. Methods A transcriptomic approach and bioinformatic tools were used to compare the profiles derived from the midguts of larvae resistant and susceptible to L. sphaericus IAB59. Results The RNA-seq profiles identified 1355 differentially expressed genes (DEGs), with 673 down- and 682 upregulated transcripts. One of the most downregulated DEGs was cqm1 , which validates the approach. Other strongly downregulated mRNAs encode the enzyme pantetheinase, apolipoprotein D, lipases, heat-shock proteins and a number of lesser known and hypothetical polypeptides. Among the upregulated DEGs, the top most encodes a peroxisomal enzyme involved in lipid metabolism, while others encode enzymes associated with juvenile hormone synthesis, ion channels, DNA binding proteins and defense polypeptides. Further analyses confirmed a strong downregulation of several enzymes involved in lipid catabolism while the assignment of DEGs into metabolic pathways highlighted the upregulation of those related to DNA synthesis and maintenance, confirmed by their clustering into related protein networks. Several other pathways were also identified with mixed profiles of down- and upregulated transcripts. Quantitative RT-PCR confirmed the changes in levels seen for selected mRNAs. Conclusions Our transcriptome-wide dataset revealed that the RIAB59 colony, found to be substantially more resistant to Bin than to the Cry48Aa/Cry49Aa toxin, developed a differential expression profile as well as metabolic features co-selected during the long-term adaptation to IAB59 and that are most likely linked to Bin resistance. Electronic supplementary material The online version of this article (10.1186/s13071-019-3661-y) contains supplementary material, which is available to authorized users.

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“…The role of each protein in these binary pairs is clearly significant to understanding the specificity of the toxins and potential binding of both components presents further challenges to prediction. The binding of both Cry48 and Cry49 to Culex brush border membrane fractions has been shown, with Cry49 suggested to be the principal binding component (Guo et al, 2016). In the case of the Bin toxin, BinB appears to be the major receptor-binding component in Culex mosquitoes but in…”

Section: Sphaericus B Thuringiensis Bacillus Cereus and Paenibamentioning

confidence: 99%

Structural classification of insecticidal proteins – Towards an in silico characterisation of novel toxins

Berry

Crickmore

2017

Journal of Invertebrate Pathology

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Article (Accepted Version) http://sro.sussex.ac.uk Berry, Colin and Crickmore, Neil (2017) Structural classification of insecticidal proteins -towards an in silico characterization of novel toxins. Journal of Invertebrate Pathology, 142. pp. 16-22. ISSN 0022-2011 This version is available from Sussex Research Online: http://sro.sussex.ac.uk/62164/ This document is made available in accordance with publisher policies and may differ from the published version or from the version of record. If you wish to cite this item you are advised to consult the publisher's version. Please see the URL above for details on accessing the published version. Copyright and reuse:Sussex Research Online is a digital repository of the research output of the University.Copyright and all moral rights to the version of the paper presented here belong to the individual author(s) and/or other copyright owners. To the extent reasonable and practicable, the material made available in SRO has been checked for eligibility before being made available.Copies of full text items generally can be reproduced, displayed or performed and given to third parties in any format or medium for personal research or study, educational, or not-for-profit purposes without prior permission or charge, provided that the authors, title and full bibliographic details are credited, a hyperlink and/or URL is given for the original metadata page and the content is not changed in any way. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Accepted Manuscript Abstract:The increasing rate of discovery of new toxins with potential for the control of invertebrate pests through next generation sequencing, presents challenges for the identification of the best candidates for further development. A consideration of structural similarities between the different toxins suggest that they may be functionally less diverse than their low sequence similarities might predict. This is encouraging from the prospective of being able to use computational tools to predict toxin targets from their sequences, however more structure/function data are still required to reliably inform such predictions.Introduction:

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Interaction of Lysinibacillus sphaericus Cry48Aa/Cry49Aa toxin with midgut brush‐border membrane fractions from Culex quinquefasciatus larvae

Cited by 13 publications

References 29 publications

Identification of Cry48Aa/Cry49Aa toxin ligands in the midgut of Culex quinquefasciatus larvae

Identification of Cry48Aa/Cry49Aa toxin ligands in the midgut of Culex quinquefasciatus larvae

A differential transcriptional profile by Culex quinquefasciatus larvae resistant to Lysinibacillus sphaericus IAB59 highlights genes and pathways associated with the resistance phenotype

Structural classification of insecticidal proteins – Towards an in silico characterisation of novel toxins

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