Adsorption on montmorillonite prevents oligomerization of Bt Cry1Aa toxin

Helassa, Nordine; Revault, M.; Quiquampoix, Hervé; Déjardin, Philippe; Staunton, Siobhán; Noinville, Sylvie

doi:10.1016/j.jcis.2011.01.064

Cited by 20 publications

(25 citation statements)

References 49 publications

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“…This profile of decreased detectability of toxins is congruent with previous studies which investigated the fate of soluble Cry3 and Cry1 toxins in different soils (1,19,21,30). It seems that the heterogeneous structure of the leaf litters is close to the structure of soils, generating the same toxin adsorption profiles (25).…”

Section: Discussionsupporting

confidence: 89%

Fate of Bacillus thuringiensis subsp. israelensis in the Field: Evidence for Spore Recycling and Differential Persistence of Toxins in Leaf Litter

Tetreau

Alessi

Veyrenc

et al. 2012

Appl Environ Microbiol

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Bacillus thuringiensis subsp. israelensis is a bioinsecticide increasingly used worldwide for mosquito control. Despite its apparent low level of persistence in the field due to the rapid loss of its insecticidal activity, an increasing number of studies suggested that the recycling of B. thuringiensis subsp. israelensis can occur under specific, unknown conditions. Decaying leaf litters sampled in mosquito breeding sites in the French Rhône-Alpes region several months after a treatment were shown to exhibit a high level of larval toxicity and contained large amounts of spores. In the present article, we show that the high concentration of toxins found in these litters is consistent with spore recycling in the field, which gave rise to the production of new crystal toxins. Furthermore, in these toxic leaf litter samples, Cry4Aa and Cry4Ba toxins became the major toxins instead of Cyt1Aa in the commercial mixture. In a microcosm experiment performed in the laboratory, we also demonstrated that the toxins, when added in their crystal form to nontoxic leaf litter, exhibited patterns of differential persistence consistent with the proportions of toxins observed in the field-collected toxic leaf litter samples (Cry4 > Cry11 > Cyt). These results give strong evidence that B. thuringiensis subsp. israelensis recycled in specific breeding sites containing leaf litters, and one would be justified in asking whether mosquitoes can become resistant when exposed to field-persistent B. thuringiensis subsp. israelensis for several generations.

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Section: Discussionsupporting

confidence: 89%

Fate of Bacillus thuringiensis subsp. israelensis in the Field: Evidence for Spore Recycling and Differential Persistence of Toxins in Leaf Litter

Tetreau

Alessi

Veyrenc

et al. 2012

Appl Environ Microbiol

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“…45 FTIR is a powerful technique for the determination of the conformational changes of proteins in interaction with surfaces. 46,47 Indeed, it is sensitive to the modication of the ratio a-helix to b-sheet.…”

Section: Stability Of Lysozyme In Layered Materials In Dry Statementioning

confidence: 99%

Structure, orientation and stability of lysozyme confined in layered materials

et al. 2013

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“…10 In these studies, electrostatic interactions between hydrophilic regions of the clay and protein polar aminoacyl residues dominated the adsorption process. However, protein adsorption on montmorillonite is generally assumed to be maximum at pH values near their iep or higher 19,[23][24][25][26] and even high ionic strengths do not necessarily prevent adsorption. 23 Likewise, Kolman and co-workers showed recently that when a protein mixture was pumped through a montmorillonite bed, adsorption was not driven by lysozyme (iep nearly 9.5)the only protein bearing a net positive charge under their experimental conditionsbut instead was the result of synergistic effects between the different proteins in mixture.…”

Section: Introductionmentioning

confidence: 99%

“…However, protein adsorption on montmorillonite is generally assumed to be maximum at pH values near their iep or higher 19,[23][24][25][26] and even high ionic strengths do not necessarily prevent adsorption. 23 Likewise, Kolman and co-workers showed recently that when a protein mixture was pumped through a montmorillonite bed, adsorption was not driven by lysozyme (iep nearly 9.5)the only protein bearing a net positive charge under their experimental conditionsbut instead was the result of synergistic effects between the different proteins in mixture. 27 Therefore, mechanisms other than electrostatic interactions have to be considered and hydrogen bonding and/or hydrophobic interactions between protein apolar amino acids and siloxane layers (or other protein fragments) may contribute to the adsorption process.…”

Section: Introductionmentioning

confidence: 99%

“…27 Therefore, mechanisms other than electrostatic interactions have to be considered and hydrogen bonding and/or hydrophobic interactions between protein apolar amino acids and siloxane layers (or other protein fragments) may contribute to the adsorption process. 23,28 Another important feature related to the adsorption of proteins on solid surfaces in general and montmorillonite in particular, concerns the structural modications of both the organic and the inorganic polymers, and various results dealing with these aspects are also reported in the literature. Fourier Transform Infra-Red spectroscopy (FTIR) and enzymatic studies for instance, have emphasized pH-dependent modication and/ or orientation of adsorbed enzymes, characterized by protein structural unfolding due to electrostatic interactions.…”

Section: Introductionmentioning

confidence: 99%

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