Ciliary reorientation is evoked by a rise in calcium level over the entire cilium.

Abstract

Internal Ca2+ levels control the pattern of ciliary and flagellar beating in eukaryotes. In ciliates, ciliary reversal is induced by a rise in intra-ciliary Ca2+, but the mechanism by which Ca2+ induces reversal is not known. We injected the fluorescent Ca2+ indicator Calcium Green into a ciliate Didinium nasutum and observed the intra-ciliary Ca2+ level during the initial reversed stroke preceding spontaneous cyclic reversed beating. In D. nasutum, Ca2+ rose throughout the length of the cilia undergoing initial reversed stroke. Electron microscopy with a combined oxalate-pyroantimonate method showed Ca2+ deposits distributed throughout the reversed cilia. We injected caged Ca2+ into D. nasutum and irradiated the base or mid region of the cilia with UV to locally increase Ca2+ concentration. Uncaging Ca2+ in the middle of the cilia produced reversal distally, but not proximally to the site of Ca2+ release. These results strongly suggest that not only Ca2+ influx sites, but also Ca2+ binding sites and vectoral bending machineries for ciliary reversal, are distributed throughout the cilium.

• Authors: Yoshiaki Iwadate, Toshinobu Suzaki
• Journal: Cell motility and the cytoskeleton (Cell Motil Cytoskeleton) Vol. 57 Issue 4 Pg. 197-206 (Apr 2004) ISSN: 0886-1544 [Print] United States
• PMID: 14752804 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright 2004 Wiley-Liss, Inc.

Chemical References

• Dextrans
• Fluorescent Dyes
• Organic Chemicals
• Oxalates
• fluorescein isothiocyanate dextran
• calcium green
• potassium antimonate
• 2-nitrophenyl-EGTA
• Egtazic Acid
• Antimony
• Fluorescein-5-isothiocyanate
• Calcium

Topics

• Animals
• Antimony (chemistry)
• Calcium (analysis, chemistry, metabolism)
• Cell Movement (drug effects, physiology)
• Cilia (drug effects, physiology, ultrastructure)
• Ciliophora (metabolism, physiology, ultrastructure)
• Dextrans (chemistry)
• Egtazic Acid (analogs & derivatives, pharmacology)
• Fluorescein-5-isothiocyanate (analogs & derivatives, chemistry)
• Fluorescent Dyes (chemistry)
• Image Processing, Computer-Assisted
• Micromanipulation (methods)
• Microscopy, Electron, Transmission
• Microscopy, Fluorescence
• Organic Chemicals
• Oxalates (chemistry)