Home About us MoEF Contact us Sitemap Tamil Website  
About Envis
Whats New
Research on Microbes
Microbiology Experts
Online Submission
Access Statistics

Site Visitors

blog tracking

Journal of Invertebrate Pathology
Vol. xx, No.
xx, 2012; Pages: xxx - xxx

Bacillus thuringiensis Cry1A toxin-binding glycoconjugates present on the brush border membrane and in the peritrophic membrane of the Douglas-fir tussock moth are peritrophins

Algimantas P. Valaitis, John D. Podgwaite

USDA Forest Service, Northern Research Station, 359 Main Road, Delaware, Ohio 43015.


Bacillus thuringiensis (Bt) Cry1A toxin-binding sites in the Douglas fir tussock moth (DFTM) larval gut were localized using immunofluorescence microscopy. Cry1Aa, Cry1Ab and Cry1Ac all bound strongly to the DFTM peritrophic membrane (PM); weaker binding of the Cry1A toxins was observed along the apical brush border of the midgut epithelium. Comparative analysis of the Cry1A toxin-binding molecules in the PM and brush border membrane vesicles (BBMV) showed that a similar toxin-binding complex was present in both. The Cry1A toxin-binding substance, a broad band with an apparent size of 180 kDa, consisted of a closely spaced doublet. The doublet was present in peritrophins, proteins tightly bound to the PM. Lectin binding studies of the PM and BBMV toxin-binding components revealed that they are glyconjugates with terminal α-GalNAc residues comprised exclusively of O-linked oligosaccharides in their glycan structures. Mild periodate oxidation, release of O-linked glycans by β-elimination, and enzymatic removal of terminal α-linked GalNAc residues with N-acetyl-α-D-galactosaminidase digestion abolished Cry1A toxin-binding to the PM and BBMV components. These data provide strong evidence that O-linked glycans are the target structures on the toxin-binding glycoconjugates for the Cry1A class of insecticidal proteins in DFTM larvae.

Keywords: Bacillus thuringiensis; Douglas-fir tussock moth;  Cry1A toxin-binding glycoconjugates; peritrophins



Copyright © 2005 ENVIS Centre ! All rights reserved
This site is optimized for 1024 x 768 screen resolution