Skip to main content
PMC home page
Infection and Immunity logoLink to Infection and Immunity
. 1985 Sep;49(3):629–634. doi: 10.1128/iai.49.3.629-634.1985

Identification of chitin as a structural component of Giardia cysts.

H D Ward, J Alroy, B I Lev, G T Keusch, M E Pereira
PMCID: PMC261227  PMID: 4030095

Abstract

The intestinal parasite Giardia lamblia is a significant cause of diarrheal disease, which is perpetuated by the infective cyst form of the parasite. Although a rational approach to the control of giardiasis would be to inhibit cyst formation, nothing is known of the chemical composition of the cyst wall or of its biosynthesis. In these studies, we have shown that chitin is a major structural component of G. lamblia and G. muris cyst walls. This conclusion is based on the finding that chitinase specifically destroys the cyst wall, as revealed by electron microscopy. The presence of chitin was also shown directly by lectin binding studies. Of 12 lectins with diverse carbohydrate recognition specificity, only the N-acetylglucosamine-specific lectins wheat germ agglutinin, succinylated wheat germ agglutinin, and tomato lectin bound to cyst walls, as shown by fluorescence microscopy and cytochemistry. Wheat germ agglutinin binding was completely abolished by treatment of the cysts with purified chitinase. This effect was specific since it could be prevented by incubating the enzyme with chitin before treatment of the cysts. Treatment of cysts with N-acetyl-beta-glucosaminidase partially inhibited wheat germ agglutinin binding, whereas other glycosidases and proteases had no effect. These findings indicate that chitin is a major structural component of Giardia cyst walls and raise the possibility that inhibitors of chitin synthesis may be of use in preventing encystation and thus controlling spread of the disease.

Full text

PDF
629

Images in this article

631Image
on p.631
631Image
on p.631
632Image
on p.632
632Image
on p.632
633Image
on p.633

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Allen A. K., Neuberger A., Sharon N. The purification, composition and specificity of wheat-germ agglutinin. Biochem J. 1973 Jan;131(1):155–162. doi: 10.1042/bj1310155. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Arroyo-Begovich A., Cárabez-Trejo A. Location on chitin in the cyst wall of Entamoeba invadens with colloidal gold tracers. J Parasitol. 1982 Apr;68(2):253–258. [PubMed] [Google Scholar]
  3. Arroyo-Begovich A., Cárabez-Trejo A., Ruíz-Herrera J. Identification of the structural component in the cyst wall of Entamoeba invadens. J Parasitol. 1980 Oct;66(5):735–741. [PubMed] [Google Scholar]
  4. Avron B., Deutsch R. M., Mirelman D. Chitin synthesis inhibitors prevent cyst formation by Entamoeba trophozoites. Biochem Biophys Res Commun. 1982 Sep 30;108(2):815–821. doi: 10.1016/0006-291x(82)90902-0. [DOI] [PubMed] [Google Scholar]
  5. Bhavanandan V. P., Katlic A. W. The interaction of wheat germ agglutinin with sialoglycoproteins. The role of sialic acid. J Biol Chem. 1979 May 25;254(10):4000–4008. [PubMed] [Google Scholar]
  6. Bingham A. K., Meyer E. A. Giardia excystation can be induced in vitro in acidic solutions. Nature. 1979 Jan 25;277(5694):301–302. doi: 10.1038/277301a0. [DOI] [PubMed] [Google Scholar]
  7. Hill D. R., Hewlett E. L., Pearson R. D. Lectin binding by Giardia lamblia. Infect Immun. 1981 Dec;34(3):733–738. doi: 10.1128/iai.34.3.733-738.1981. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Marx J. L. Chitin synthesis inhibitors: new class of insecticides. Science. 1977 Sep 16;197(4309):1170–1172. doi: 10.1126/science.197.4309.1170. [DOI] [PubMed] [Google Scholar]
  9. Meyer E. A., Radulescu S. Giardia and giardiasis. Adv Parasitol. 1979;17:1–47. doi: 10.1016/s0065-308x(08)60548-5. [DOI] [PubMed] [Google Scholar]
  10. Monsigny M., Roche A. C., Sene C., Maget-Dana R., Delmotte F. Sugar-lectin interactions: how does wheat-germ agglutinin bind sialoglycoconjugates? Eur J Biochem. 1980 Feb;104(1):147–153. doi: 10.1111/j.1432-1033.1980.tb04410.x. [DOI] [PubMed] [Google Scholar]
  11. Nachbar M. S., Oppenheim J. D., Thomas J. O. Lectins in the U.S. Diet. Isolation and characterization of a lectin from the tomato (Lycopersicon esculentum). J Biol Chem. 1980 Mar 10;255(5):2056–2061. [PubMed] [Google Scholar]
  12. Pereira M. E., Kabat E. A. Immunochemical studies on lectins and their application to the fractionation of blood group substances and cells. CRC Crit Rev Immunol. 1979 Nov;1(1):33–78. [PubMed] [Google Scholar]
  13. Roberts-Thomson I. C., Stevens D. P., Mahmoud A. A., Warren K. S. Giardiasis in the mouse: an animal model. Gastroenterology. 1976 Jul;71(1):57–61. [PubMed] [Google Scholar]
  14. Sheffield H. G., Bjorvat B. Ultrastructure of the cyst of Giardia lamblia. Am J Trop Med Hyg. 1977 Jan;26(1):23–30. doi: 10.4269/ajtmh.1977.26.23. [DOI] [PubMed] [Google Scholar]
  15. de Miranda Santos I. K., Pereira M. E. Lectins discriminate between pathogenic and nonpathogenic South American trypanosomes. Am J Trop Med Hyg. 1984 Sep;33(5):839–844. doi: 10.4269/ajtmh.1984.33.839. [DOI] [PubMed] [Google Scholar]

Articles from Infection and Immunity are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES