title: Analysis of three-dimensional ciliary beating by means of high-speed stereomicroscopy.
abstract: Results are presented on the analysis of three-dimensional motion of compound cilia or cirri in voltage-clamped specimens of the protozoan Stylonychia mytilus. Time series of three-dimensional data were obtained by using the anaxial illumination method for simultaneous recording of stereoscopic video images. Data processing involved the following steps: determination of a reference coordinate system based solely on features present in each stereo-pair; tracing of cirral axes in digitized images, conversion to parameter curves by means of least-squares polynomial approximation, conversion of pairs of two-dimensional data to a series of three-dimensional data; correction for distortion due to projective shortening and conversion to a series of polynomial triplets, and analysis of the periodical components of the motion pattern in the frequency domain. Reconstructed beating cycles show typical differences between hyperpolarization-induced ciliary activity and depolarization-induced ciliary activity. Reconstructions of the motion of the basal segment of a cirrus are in agreement with existing data. Analysis of the curvature and torsion of a cirral axis during beating does not reveal any simple pattern of propagated activity within the axoneme. The return stroke may be subdivided into two phases. First, a curvature peak develops proximally. Secondly, a region with increased torsion arises more distally and spreads out in proximal direction. Both curvature and torsion return to minimal values by the beginning of the power stroke.
authors.affiliation: Arbeitsgruppe Zelluläre Erregungsphysiologie, Ruhr-Universität Bochum, Germany.
authors.forename: P F
authors.initials: PF
authors.lastname: Teunis
authors.forename: H
authors.initials: H
authors.lastname: Machemer
mesh_terms: D000818:Animals; D002465:Cell Movement; D002923:Cilia / Q000502:physiology* / Q000648:ultrastructure; D056890:Eukaryota / Q000502:physiology*; D005583:Fourier Analysis; D007700:Kinetics; D008433:Mathematics; D018715:Microscopy, Video / Q000379:methods; D008954:Models, Biological; D013997:Time Factors