ENZYMOLOGY OF EGGSHELL FORMATION IN SCHISTOSOMA MANSONI

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The long term objective of this lab is to study development in Schistosoma mansoni, especially factors affecting the development of female worms. A central need of these studies is a marker to assess the developmental status of female worms. The enzymes involved in eggshell protein activation and cross linking are only expressed in adult, sexually active female worms. Enzymatic assays and molecular probes will be developed to monitor the expression of these enzymes. These enzymes will therefore serve as markers for female worm development. A parallel objective of this lab is to apply the knowledge gained in fundamental investigations of worm biochemistry and molecular biology to the generation of novel methods of schistosomiasis control. Schistosome eggs are of central importance in the pathology and transmission of schistosomiasis. A better understanding of the biochemical and molecular events involved in the production of eggs in the female schistosome may also lead to the development of novel chemotherapies or a schistosome vaccine. The specific research proposed in this application is to identify the enzymes involved in eggshell formation in female S. mansoni. Our working hypothesis is that eggshell formation is schistosomes uses enzymatic pathways similar to those used for eggshell formation and cuticle hardening by arthropods and mollusks; the enzymes of quinone tanning and Beta-sclerotization. The role that tyrosine hydrolase, phenol oxidase, and peroxidase play in schistosome eggshell production will be investigated. The goals of this project are 1) to determine role of peroxidase in eggshell formation; 2) to determine the role of tyrosine hydroxylase in the hydroxylation of schistosome eggshell proteins; 3) to determine the relationship of schistosome phenol oxidase to the phenol oxidases of other organisms by cloning its gene; 4) to understand the role of phenol oxidase in the hydroxylation and oxidation of schistosome eggshell proteins; and 5) to determine the stage and tissue specific expression phenol oxidase in schistosomes.