Nutritional Relationships in Schistosomiasis.
Abstract
Amino acids, sugars, purines, and pyrimidines enter the tegument of adult Schistosoma mansoni by both diffusion and mediated processes. In all examples, the mediated processes are specific, and demonstrate saturation kinetics as well as inhibition by closely related molecular species. The concentration of amino acids in mouse hepatic portal serum approximated the respective transport constants (K sub t) determined in vitro. Purines and pyrimidines also enter the adult parasite by both mediated and diffusion processes. Five distinct though complex transport loci were identified. Nucleotides are primarily dephosphorylated at the tegumental surface prior to permeation. The phosphodydrolase is not involved in the hydrolosis of sugar phosphates, nor is it (they) sensitive to Na+ for cysteine. Like the above organic solute, the sugars enter the parasite by a mixed mode--both diffusion and mediated systems being utilized. The mediated system is apparently Na+ dependent and sensitive to presence of ouabain, phlorizin, phloretin. Hexose mediated accumulation is Na+ coupled. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1978
- Accession Number
- ADA086363
Entities
People
- Clark P. Read
- Frank M. Fisher Jr.
Organizations
- Rice University