Sugar detection with fluorescein isothiocyanate-labeled lectins in hemolymph proteins of the silkworm, Bombyx mori (Lepidoptera : Bombycidae)

Sugar moieties of glycoproteins in silkworm hemolymph were examined with fl uorescein isothiocyanate (FITC)-labeled lectins. The glycoproteins were sep arated by polyacrylamide gel electrophoresis (PAGE) and transferred to a hy drophobic polyvinylidene difluoride membrane. The membranes were treated wi th several kinds of FITC-labeled lectins. A glycoprotein of 130 kDa molecul ar weight was the principal glycoprotein on the electrophoretogram and was found to react well with lectins from Canavalia ensiformis, Lens culinaris and Pisam sativum. The silkworm hemolymph proteins including the 130k-glyco protein did not react with lectins from Triticum vulgaris, Limulus polyphem us and Vicia villosa, while the control substances, sheep blood proteins an d fetuin, a plasma glycoprotein from calf serum, reacted with the lectin fr om T vulgaris. These findings indicate that the main terminal residue of th e sugar side chains of the 130k-glycoprotein in the silkworm hemolymph is n ot N-acetyl neuraminic acid (NANA) or N-acetyl glucosamine but mannose or g lucose or N-acetyl galactosamine.