Speract, a sperm-activating peptide (SAP) from sea urchin eggs, induces various sperm responses including a transient increase in the intracellular Ca2 concentration. However, it has not been clarified how speract modulates sperm motility and whether it functions as a chemoattractant. To confirm the effect of speract on sperm motility, we observed the flagellar bending response to speract in sperm of Hemicentrotus pulcherrimus, in experiments using caged speract and a lighting system for a microscope newly developed with a power LED. We found that speract induces increases in curvature of swimming paths and changes flagellar bending shape to asymmetric. These facts show that speract directly regulates flagellar motility, and suggest that speract-induced increases in intracellular Ca2 concentration play an actual role in regulation of the flagellar movement.
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1 March 2005
Sperm-Activating Peptide Induces Asymmetric Flagellar Bending in Sea Urchin Sperm
Kogiku Shiba,
Junko Ohmuro,
Yoshihiro Mogami,
Takuya Nishigaki,
Christopher D. Wood,
Alberto Darszon,
Yoshiro Tatsu,
Noboru Yumoto,
Shoji A. Baba
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caged peptide
flagella
Hemicentrotus pulcherrimus
sea urchin sperm
speract