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Edward L.
Jarroll
Professor of Parasitology
Associate Dean, College of A & S
Ph.D., West Virginia University
Research
Areas:
Parasite Biochemistry and Metabolism
Email: e.jarroll@neu.edu
Phone:
617.373.2260
Fax: 617.373.3724
Location:
102 Meserve Hall
Mail: NU/Biology
134 Mugar Life Sciences
360 Huntington Avenue
Boston, MA 02115
USA
Research Description
My interests lie in the study of protozoan biochemistry and metabolism especially as it applies to cytodifferentiation, energetics and chemotherapy. I am using Giardia intestinalis, the causative agent for giardiasis and a primary cause of waterborne intestinal disease in humans, as the model for these studies since we can now culture, excyst and encyst this parasite in vitro. The current focus of my research is the regulation and control of the pathway of N-acetylgalactosamine synthesis and subsequent cyst wall assembly which occurs during encystment. G. intestinalis trophozoites encyst when induced by perhaps, because of cholesterol deprivation. Within 6 hr, OU, normally stimulated by Glc and inhibited by MTZ, doubles. By 12 hr, OU decreases and becomes refractory to stimulation by glucose or inhibition by MTZ. Also, trophozoites begin making cyst walls with membranous and filamentous portions. UDP-GalNAc is synthesized from endogenous Glc by enzymes, the activities of which are induced: GlcNH2 6-P isomerase (Gpi) reversibly converts fructose 6-P (F6P) to GlcNH26P which is reversibly acetylated by GlcNH26P N-acetylase(Gna) to GlcNAc6P and converted to GlcNAc1P by phosphoacetylglucosamine mutase (Pgm). Gpi's product, glucosamine 6-phosphate (GlcNH26P), activates UDP-N-acetylglucosamine pyrophosphorylase (Gpp) anabolically. GlcNAc1P and UTP are reversibly converted to UDP-GlcNAc by UDP-GlcNAc pyrophosphorylase (Gpp) and UDP-GlcNAc is epimerized to UDP-GalNAc by UDP-GlcNAc 4'-epimerase (G4e). The UDP-GalNAc is polymerized by "cyst wall synthase" into a polysaccharide, which, in conjunction with polypeptides, forms the filamentous outer cyst wall of Girardia (Fig. 1).
Selected
Publications
Karr, C. and Jarroll, E. 2004. Cyst Wall Synthase:
N-acetylgalactosaminyltransferase activity is induced to form the novel
GalNAc polysaccharide in the Giardia cyst wall. Microbiology. 150:1237-1243
Sener,K., Shen,Z., Newburg, D. and Jarroll, E. 2004.
Amino sugar phosphate levels change during formation of the Giardia
cyst wall. Microbiology. 150: 1225-1230.
Gerwig, G., van Kuik, J.A., Leeflang, B., Kamerling, J., Vliegenthart,
J., Karr, C. and Jarroll, E. 2002. Conformational studies
of the (1-3) -N-acetyl-D-galactosamine polymer of the Giardia lamblia
filamentous cyst wall. Glycobiology. 12(6):1-7.
Bulik, D., van Ophem, P., Manning, J., Shen, Z., Newburg, D.
and Jarroll, E. 2000. UDP-N-Acetylglucosamine Pyrophosphorylase:
A Key Enzyme in Encysting Giardia is Allosterically Regulated.
Journal of Biological Chemistry. 275:14722-14728.
Paget, T.A., Macechko, P.T., and Jarroll, E. 1998.
Giardia intestinalis: Metabolic changes during cytodifferentiation.
Journal of Parasitology 84: 222-226.
Steimle, P., Lindmark, D., and Jarroll, E. 1997.
Purification and characterization of glucosamine 6-phosphate isomerase
from encysting Giardia. Molcular and Biochemical Parasitology
84: 149-153.
Erlandsen, S., Macechko, P.T., van Keulen, H., and Jarroll,
E.L. 1996. Formation of the Giardia cyst wall:
Studies on extracellular assembly using immunogold labeling and high
resolution field emission SEM. Journal of Eukaryotic Microbiology 43:
416-429.
Ellis, J., M. Wyder, E. Jarroll, and E. Kaneshiro. 1996. Changes in lipid composition during in vitro encystation and fatty acid desaturase activity of Giardia lamblia. Molecular and Biochemical Parasitology 81: 13-25
Bulik, D., Lindmard, D., and Jarroll, E. 1998. Purification and characterization of UDP-N-acetylglucosamine pyrophosphorylase from encysting Giardia. Molcular and Biochemical Parasitology (accepted).
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