Isolation and partial characterization of the tegumental outer membrane of schistosomula of Schistosoma mansoni

Francesca Levi-Schaffer*, Rebeca Tarrab-Hazdai, Michelle D. Schryer, Ruth Arnon, Moshe Smolarsky

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

40 Scopus citations

Abstract

Separation of the external membranes from freshly converted mechanical schistosomula of Schistosoma mansoni was achieved by osmotic shock under hypertonic conditions, followed by mechanical shearing and ultracentrifugation. Prior to treatment, the schistosomula were surface labeled by introduction of N-DNP-ε-aminocaproylphosphatidylethanolamine molecules into their lipid bilayer followed by anti-DNP antibodies and stained with either 125I-protein-A or ferritin labeled secondary anti-DNP antibodies. This label provided a membrane marker by which the purity of the preparation could be assessed at each stage. Fluorescence staining with FITC-conjugated secondary antibodies prior to treatment revealed that the homogeneously stained membrane of the intact schistosomula became swollen and ruptured after the osmotic shock. The isolated membrane pellet was intensely fluorescent. Electron microscopical examination revealed mostly vesicles, some of them with organized multilayer assembly. The vesicles were ferritin labeled, indicating that they originated from the outer surface membrane of the schistosomula. A 100 fold enrichment in the alkaline phosphatase activity and about 300 fold enrichment in acetylcholinesterase activity in the membrane preparations, as compared to the intact schistosomula, was found. The isolated tegument was analyzed by SDS-polyacrylamide gel electrophoresis. The pattern obtained showed three major bands, of molecular weights 69 000, 45 000 and 12 000 alongside with a large number of minor bands. Immunoprecipitation of the isolated 125I-labeled membrane antigens with antisera from chronically infected mice revealed these three major bands together with three other bands of molecular weight 38 000, 23 000 and 16 000.

Original languageAmerican English
Pages (from-to)283-300
Number of pages18
JournalMolecular and Biochemical Parasitology
Volume13
Issue number3
DOIs
StatePublished - Nov 1984
Externally publishedYes

Bibliographical note

Funding Information:
We are grateful to Mr. Y. Chalaf for the maintenance of the parasite life cycle, to Q.F.B. Gonzales for her excellent technical assistance and to Mrs. B. Romano and Mr. S. Hammelhoch for help in electron microscopy studies. This work was supported in part by grant No. RF 79062 from the Rockefeller Foundation and grant No. 281-0017 by the Edna McConnell Clark Foundation.

Keywords

  • Membrane isolation
  • Schistosoma mansoni
  • Schistosomula

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