Binding of Bacillus thuringiensis Cry1 toxins to the midgut brush border membrane vesicles of Chilo suppressalis (Lepidoptera : Pyralidae) : evidence of shared binding sites

Fiuza Lidia Mariana, Nielsen Leroux Christina, Gozé Eric, Frutos Roger, Charles Jean François. 1996. Binding of Bacillus thuringiensis Cry1 toxins to the midgut brush border membrane vesicles of Chilo suppressalis (Lepidoptera : Pyralidae) : evidence of shared binding sites. Applied and Environmental Microbiology, 62 (5) : 1544-1549.

https://doi.org/10.1128/AEM.62.5.1544-1549.1996

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Autre titre : Fixation des toxines Cry1 de Bacillus thuringiensis aux vésicules membranaires de la bordure en brosse de l'intestin moyen de Chilo suppressalis (Lepidoptera : Pyralidae) : mise évidence des portions de sites de fixation

Résumé : Binding and competition among Cry1Aa, Cry1Ac, and Cry1Ba toxins were analyzed quantitatively #in vitro# by using 125 I-labeled activated toxins and brush border membrane vesicles isolated from #Chilo suppressalis# larval midguts. The three toxins bound specifically to the midgut brush border vesicles. Direct binding experiments showed that Cry1Aa and Cry1Ba recognized a single class of binding sites with different affinities, whereas Cry1Aa recognized two classes of binding sites, one with a high affinity and low concentration and the other with a lower affinity but higher concentration. Competition experiments showed that toxins Cry1Ac and Cry1Ba shared a binding site in the #C. suppressalis# midgut membranes and that this site was also the low-affinity binding site for Cry1Aa.

Mots-clés Agrovoc : Bacillus thuringiensis, Chilo suppressalis, toxine bactérienne, réaction biochimique, réaction de fixation du complément

Classification Agris : H10 - Ravageurs des plantes

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