Studies using Mongolian gerbils found that during a primary infection with Giardia lamblia trophozoites, disaccharidase activities were decreased from day 10 post-infection (p.i.) until well past elimination of the parasite. However, during a challenge infection, enzyme deficiencies were short-lived. A challenge with a soluble extract of G. lamblia trophozoites also resulted in reductions in disaccharidase activity. The degree of these reductions in enzyme activity was dependent on the extract dose. Gel filtration of the trophozoite crude extract resulted in fractions F1, F2, and F3. However, only a challenge with F1 led to disaccharidase deficiencies. Further separation of F1 resulted in fractions F1a and F1b. Impairments of enzyme activity were obtained only in gerbils challenged with F1b. Protein analysis of F1b revealed several high and low molecular weight bands. When gerbils previously exposed to G. lamblia were challenged with an extract of Entamoeba histolytica trophozoites, disaccharidase activities remained comparable to controls. Moreover, enzyme levels in gerbils challenged with excretory/secretory G. lumblia products were affected in a manner which was inconsistent with the live parasitic challenge. Results suggest that the disaccharidase deficiencies in giardiasis are parasite-specific and are induced by a heat-stable constituent(s) of fraction F1b, possibly through an immune response to an antigenic component of this parasite fraction.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.55514 |
| Date | January 1994 |
| Creators | Mohammed, Shawn Rasheed |
| Contributors | Faubert, Gaetan M. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Master of Science (Institute of Parasitology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001443072, proquestno: AAIMM00041, Theses scanned by UMI/ProQuest. |
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