Giardia lamblia is a significant cause of diarrheal disease worldwide which is perpetuated by the infective cyst form of the parasite. The mechanisms underlying the process of differentiation from trophozoite to cyst are poorly understood. The overall purpose of this project is to decipher the biochemical and molecular events involved in this process, focusing on structure and function of carbohydrate moieties in both trophozoite and cyst.
The specific aims of this proposal are directed at a) elucidating structural and biosynthetic aspects of N-acetyl-glucosamine containing carbohydrate moieties which have been identified as chitin in cyst walls as well as linked to glycoproteins in trophozoites and cysts and b) relating these aspects to the biological role of these moieties in differentiation of the parasite.
The first aim i s to determine the structure and linkage of the GIcNAc residues in trophozoite and cyst glycoproteins with the long term objective of studying their biosynthesis and ascertaining whether they serve as precursor moieties for chitin synthesis which is a key event in differentiation.
The second aim i s to characterize, purify and produce antibodies to chitin synthase which is a developmentally regulated enzyme involved in the biosynthesis of chitin. These studies will facilitate the long term objective of delineating genetic control of differentiation at the molecular level by identifying cyst and trophozoite specific genes encoding developmentally regulated proteins.
The third aim i s to determine the subcellular localization of chitin and chitin precursors as well as the N-acetyl-glucosamine containing glycoproteins at the ultrastructural level. The last aim is to relate the findings obtained at the structural and biochemical level to growth and differentiation of the parasite in vitro as well as in vivo in animal models of giardiasis. The ultimate goal is to design strategies to arrest differentiation, interrupt the life cycle of the parasite and control spread of the disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29AI027218-05
Application #
2063760
Study Section
Tropical Medicine and Parasitology Study Section (TMP)
Project Start
1990-08-01
Project End
1995-05-31
Budget Start
1994-06-01
Budget End
1995-05-31
Support Year
5
Fiscal Year
1994
Total Cost
Indirect Cost
Name
Tufts University
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02111