Histochemical analysis of Bacillus thuringiensis CrylA toxin binding to midgut epithelial cells of Bombyx mori

Delwar M. Hossain, Tohru Hayakawa, Yasuyuki Shitomi, Kimiko Itoh, Toshiaki Mitsui, Ryoichi Sato, Hidetaka Hori

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


We analyzed the binding of the Bacillus thuringiensis insecticidal toxins, CrylAa, CrylAb and CrylAc, to midgut tissue of the silkworm, Bombyx mori with ligand blot analysis and histochemical observations. CrylAa, CrylAb and CrylAc bound to unique sets of proteins in various subcellular fractions prepared by centrifugation. CrylAa bound to various proteins in all subcellular fractions, whereas CrylAb bound to a single protein of ∼180 kDa in all fractions as shown by Western blot analysis. Cry1Ac bound to proteins which were primarily ∼100-120 kDa in all fractions. CrylA toxins were labeled with fluorescent dye and Cy3-labeled CrylAa, CrylAb and CrylAc were shown to localize primarily to the apical membrane region. However, they also localized to basement or basolateral membranes. The distribution of a 252-kDa membrane protein (P252) of the B. mori midgut, which was recently identified as a plausible candidate for receptor of CrylA toxins were also examined with histochemical methods. Substantial signals of FITC-labeled antibody against P252, even though not all, were evident in the apical cells, and these were coincident with Cy3-CrylAa and Cy3-CrylAc signals.

Original languageEnglish
Pages (from-to)30-38
Number of pages9
JournalPesticide Biochemistry and Physiology
Issue number1
Publication statusPublished - Jan 2007
Externally publishedYes


  • Bacillus thuringiensis
  • Bombyx mori midgut
  • Cy3-labeled CrylA
  • Fluorescent microscope
  • Histochemistry
  • Insecticidal proteins

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Health, Toxicology and Mutagenesis


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