Related Experiment Videos
Schistosoma mansoni: eggshell formation is regulated by pH and calcium.
1Department of Molecular Biology, University of Wyoming, Laramie 82071.
Experimental Parasitology
|October 1, 1991
Summary
Schistosome eggshell formation is triggered by alkalinization, which causes precursor aggregation within secretory vesicles. This process, observed via autofluorescence and electron microscopy, stabilizes the eggshell in trematodes.
Area of Science:
- Parasitology
- Biochemistry
- Cell Biology
Background:
- Schistosome eggshell precursors are synthesized and stored in secretory vesicles within vitelline cells.
- These vesicles contain an emulsion of eggshell precursor material, stabilized by acidity.
Purpose of the Study:
- To investigate the mechanism of schistosome eggshell formation.
- To elucidate the role of vesicle acidity and alkalinization in eggshell precursor aggregation and cross-linking.
Main Methods:
- Induction of eggshell formation using alkalinizing treatments.
- Analysis of autofluorescence and electron microscopy to observe precursor aggregation.
- Isolation and biochemical characterization of aggregated eggshell precursors.
- Induction of exocytosis using calcium ionophore A23187.
Main Results:
- Alkalinization triggers eggshell formation within secretory vesicles, characterized by autofluorescence and precursor aggregation into microspined particles.
- Isolated aggregates exhibit protease resistance and amino acid composition similar to authentic eggshell.
- Calcium ionophore A23187 induces exocytosis of eggshell material.
Conclusions:
- A model for schistosome eggshell formation is proposed, involving stabilization of precursor emulsions by vesicle acidity.
- Alkalinization initiates eggshell assembly within secretory vesicles.
- The proposed model may be applicable to eggshell formation in other trematodes.