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Updated: Aug 8, 2026
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Phosphopeptide Analysis of Rodent Epididymal Spermatozoa
Published on: December 30, 2014
Peptide-induced hyperactivation-like vigorous flagellar movement in starfish sperm
Kogiku Shiba1, Tomoko Tagata, Junko Ohmuro
1Department of Advanced Biosciences, Graduate School of Humanities and Sciences, Ochanomizu University, 2-1-1 Otsuka, Tokyo 112-8610, Japan.
Zygote (Cambridge, England)
|May 17, 2006
Summary
Asterosap, a sperm-activating peptide, alters starfish sperm motility. It enhances flagellar bending and beat frequency in attached sperm, potentially aiding the acrosome reaction.
Area of Science:
- Marine Biology
- Reproductive Biology
- Biochemistry
Background:
- Asterosap is a sperm-activating peptide (SAP) from starfish egg jelly.
- It influences cGMP signaling in starfish sperm, similar to sea urchin resact.
- Asterosap is involved in inducing the acrosome reaction.
Purpose of the Study:
- To evaluate how asterosap modulates sperm motility before the acrosome reaction.
- To analyze the effect of asterosap isoform P15 on starfish sperm flagellar movement.
Main Methods:
- Starfish sperm (Aphelasterias japonica) were analyzed in artificial seawater (ASW).
- Sperm were exposed to ASW containing 1 micromol/L of asterosap isoform P15.
- Flagellar movement was analyzed, comparing free-swimming sperm and sperm attached to a surface.
Main Results:
- In P15, free-swimming sperm exhibited straighter and more symmetrical flagellar movement than in ASW, with no significant change in beat frequency or velocity.
- Attached sperm in P15 showed dramatically different flagellar movement: greater bending, higher curvature, increased shear angle, and higher beat frequency compared to ASW.
- This vigorous movement in P15 under high-load conditions may enhance propulsive forces.
Conclusions:
- Asterosap (P15) significantly alters starfish sperm flagellar mechanics, particularly under load.
- The enhanced flagellar activity may facilitate sperm penetration through the egg jelly layer.
- This modulation of motility is crucial for efficient acrosome reaction induction.
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