title: Purification of a fraction of Giardia lamblia trophozoite extract associated with disaccharidase deficiencies in immune Mongolian gerbils (Meriones unguiculatus).
abstract: The effects on disaccharidase activities of challenging gerbils previously exposed to Giardia lamblia with fradions of the crude trophozoite extract were examined. Gel filtration of the soluble extract on a Sephacryl S-200 HR column resulted in 3 fradions: F1, F2 and F3. Only a challenge with fraction F1 (0.1 mg total dose) was found to induce disaccharidase deficiencies. Boiling F1 prior to challenge did not change this effect on the enzyme activities. However, the decreases were not obtained when the total F1 dose was reduced to 0.05 mg. Column chromatography of fraction F1 under dissociating and reducing conditions resulted in 2 further fractions: F1a and F1b. Challenging immune gerbils with F1b led to impairments of disaccharidose activity similar to those obtained with F1. Protein analysis of the crude extract, as well as the fractions of the extract, revealed several high and low molecular weight bonds. These findings indicate that a constituent(s) of fraction F1b is the portion of the parasite which induces disaccharidase deficiencies in immune gerbils. This fraction consists of proteins ranging in molecular weight from 32 to 200 kDa. In addition the G. lamblia fraction involved in the decreases in enzyme activity is heat-stable.
authors.affiliation: Institute of Parasitology of McGill University, Québec, Canada.
authors.forename: S R
authors.initials: SR
authors.lastname: Mohammed
authors.forename: G M
authors.initials: GM
authors.lastname: Faubert
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry / Q000302:isolation & purification; D002850:Chromatography, Gel; D004186:Disaccharidases / Q000172:deficiency*; D004591:Electrophoresis, Polyacrylamide Gel; D005849:Gerbillinae; D016829:Giardia lamblia / Q000737:chemistry* / Q000276:immunology; D005873:Giardiasis / Q000201:enzymology* / Q000276:immunology / Q000469:parasitology; D007421:Intestine, Small / Q000201:enzymology; D008297:Male; D008970:Molecular Weight; D015800:Protozoan Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*
chemical_list: D000953:Antigens, Protozoan; D015800:Protozoan Proteins; D004186:Disaccharidases