Acta Biologica Hungarica

, Volume 52, Issue 4, pp 473–484 | Cite as

The Immunoprotein Scolexin and Its Synthesizing Sites — The Midgut Epithelium and the Epidermis

  • Kinga MolnárEmail author
  • Noemi H. Borhegyi
  • Gy. Csikós
  • M. Sass


Scolexin is one of the bacterial induced hemolymph proteins of tobacco hornworm (Manduca sexta) larvae, that has hemocyte coagulation-provoking activity. The 72 kDa scolexin complex is composed of two 36 kDa subunits. To examine the protein secretory pathways in insect epithelia a polyclonal antibody was raised against the 36 kDa hemolymph protein. This MsH36 antibody recognised a 36 and a 72 kDa protein in tissue homogenates. On the basis of the characteristic labelling pattern observed on immunoblots and immunocytochemical sections we concluded that the 36 kDa protein in the hemolymph, in the midgut and in the epidermis was identical with the scolexin subunit. In present paper we report a labelling shift in the midgut epithelium between goblet and columnar cells that may be controlled by the hormonal system. A 72 kDa protein showed similar epitops and molecular weight to the scolexin complex and was detected in epidermis and in cuticle under both reducing and non-reducing conditions. Tissue localization of 36 kDa and 72 kDa MsH36 antibody labelling proteins indicated the possibility that the epidermal cells produce two kinds of scolexin-like proteins. The complex composed of 36 kDa subunits are transported basolaterally into the circulation and display hemocyte coagulation inducing activity while the 72 kDa form contains two subunits linked covalently secreted apically into the cuticle.


Scolexin secretory pathway midgut epidermis cuticle 


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  1. 1.
    Aronson, A. I., Geng, C., Wu, L. (1999) Aggregation of bacillus thuringiensis Cry1A toxins upon binding to target insect larval midgut vesicles. Appl. Environ. Microbiol. 65, 2503–2507.PubMedCentralGoogle Scholar
  2. 2.
    Borhegyi, H. N., Molnár, K., Csikös, Gy., Sass, M. (1999) Isolation and characterisation of an apically sorted 41 kDa protein from the midgut of tobacco hornworm (Manduca sexta). Cell Tissue Res. 297, 513–525.CrossRefGoogle Scholar
  3. 3.
    Cioffi, M. (1979) The morphology and fine structure of the larval mindgut of a moth (Manduca sexta) in relation to active ion transport. Tissue Cell 11, 467–479.CrossRefGoogle Scholar
  4. 4.
    Csikós, Gy, Molnár, K., Borhegyi, H. N., Talián, Cs. G., Sass, M. (1999) Insect cuticle, an in vivo model of protein trafficking. J. Cell Sci. 112, 2113–2124.PubMedGoogle Scholar
  5. 5.
    Finnerty, C. M., Granados, R. R. (1997) The plasma protein scolexin from Manduca sexta is induced by baculovirus infection and other immune challenges. Insect Biochem. Mol. Biol. 27, 1–7.CrossRefGoogle Scholar
  6. 6.
    Finnerty, C. M., Granados, R. R., Hughes, P. R., Belotti, A. C. (1994) Bioassay of several baculoviruses for virus induced mortality in Manduca sexta larvae and induction of infection-specific protein. J. Invert. Path. 63, 140–144.CrossRefGoogle Scholar
  7. 7.
    Finnerty, C. M., Karplus, P. A., Granados, R. R. (1999) The insect immune protein scolexin is a novel serine proteinase homolog. Protein Science 8, 242–248.CrossRefGoogle Scholar
  8. 8.
    Hua, G., Tsukamoto, K., Rasilo, M. L., Ikezawa, H. (1999) Molecular cloning of a GPI-anchored aminopeptidase N from Bombyx mori midgut: a putative receptor for Bacillus thuringiensis CryIA toxin. Gene 214, 177–185.CrossRefGoogle Scholar
  9. 9.
    Hughes, J. A., Hurlbert, R. E., Rupp, R. A., Spence, K. D. (1983) Bacteria-induced haemolymph proteins of Manduca sexta pupae and larvae. J. Insect. Physiol. 29, 625–632.CrossRefGoogle Scholar
  10. 10.
    Hurlbert, R. E., Karlinsey, J. E., Spence, K. D. (1985) Differential synthesis of bacteria-induced proteins of Manduca sexta larvae and pupae. J. Insect. Physiol. 31, 205–215.CrossRefGoogle Scholar
  11. 11.
    Kyriakides, T. R., McKillip, J. L., Spence, K. D. (1995) Biochemical characterization, developmental expression, and induction of the immune protein scolexin from Manduca sexta. Arch. Insect Biochem. Physiol. 29, 269–280.CrossRefGoogle Scholar
  12. 12.
    Laemmli, U. K. (1970) Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227, 680–685.CrossRefGoogle Scholar
  13. 13.
    Locke, M., Kiss, A., Sass, M. (1994) The cuticular localization of integument peptides from particular routing categories. Tissue Cell 26, 707–734.CrossRefGoogle Scholar
  14. 14.
    Marcu, O., Locke, M. (1999) The origin, transport and cleavage of the moult-associated cuticular protein CECP22 from Calpodes ethlius (Lepidoptera, Hesperidae). J. Insect Physiol. 45, 861–870.CrossRefGoogle Scholar
  15. 15.
    Minnick, M. F., Rupp, R. A., Spence, K. D. (1986) A bacterial-induced lectin which triggers hemocyte coagulation in Manduca sexta. Biochem. Biophys. Res. Comm. 137, 729–735.CrossRefGoogle Scholar
  16. 16.
    Minnick, M. F., Spence, K. D. (1988) Tissue site and modification of a bacteria induced coagulation protein in Manduca sexta. Insect Biochem. 18, 637–644.CrossRefGoogle Scholar
  17. 17.
    Palli, S. R., Locke, M. (1987) The synthesis of hemolymph proteins by the larval midgut of an insect Calpodes ethlius (Lepidoptera: Hesperidae). Insect Biochem. 17, 561–572.CrossRefGoogle Scholar
  18. 18.
    Russell, V. W., Dunn, P. E. (1991) Lysosyme in the midgut of Manduca sexta during metamorphosis. Arch. Insect Biochem. Physiol. 17, 67–80CrossRefGoogle Scholar
  19. 19.
    Samuels, R. I., Reynolds, S. E. (1993) Moulting fluid enzymes of the tobacco hornworm, Manduca sexta: timing of proteolytic and chinolytic activity in relation to pre-ecdysial development. Arch. Insect Biochem. Physiol. 24, 33–44.CrossRefGoogle Scholar
  20. 20.
    Sass, M., Kiss, A., Locke, M. (1993) Classes of integument peptides. Insect Biochem. Mol. Biol. 23, 845–857.CrossRefGoogle Scholar
  21. 21.
    Towbin, H., Staehelin, T., Gordon, J. (1979) Electroforetic transfer of proteins from polyacrylamide gels to nitrocellulose sheets: procedure and some application. Nat. Acad. Sci. USA 76, 4350–4354.CrossRefGoogle Scholar
  22. 22.
    Willott, E., Trenczek, T., Thrower, L.W., Kanost, M. R. (1994) Immunochemical identification of insect hemocyte populations: monoclonal antibodies distinguish four major hemocyte types in Manduca sexta. Eur. J. Cell. Biol. 65, 417–423.PubMedGoogle Scholar

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© Akadémiai Kiadó, Budapest 2001

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (, which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  • Kinga Molnár
    • 1
    Email author
  • Noemi H. Borhegyi
    • 1
  • Gy. Csikós
    • 1
  • M. Sass
    • 1
  1. 1.Department of General ZoologyEötvös Loránd UniversityBudapestHungary

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