Directional Change and Transformation of Sliding F-actin Analyzed by a Semi-Automatic Image Tracking System

Satoshi Hasegawa^1,2, Rieko Shimo¹ and Koshin Mihashi¹

¹Graduate School of Mathematics, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
²School of Information Culture, Nagoya Bunri University, Inazawa, Aichi 492-8520, Japan

(Received March 1, 2001; Accepted July 25, 2001)

Keywords: Image Analysis, Pattern Matching, Actin Filament, in vitro Motility Assay, Living Motion

Abstract. We have developed a semi-automatic image tracking system to analyze the longitudinal sliding and transformation of a string-like object. By using this system, we made a moving image analysis on actin filament (F-actin) in an in vitro motility assay. In this assay, F-actin was sliding on the surface under a fluorescent microscope. The tracking system pursues the fluorescent image of F-actin by matching a polygon line model with the video images. In this study, the directional change and the curvatures of the sliding F-actin were statistically analyzed using the data obtained by the tracking system. The simplified sliding motion of the polygon line model was simulated on a computer. By comparing the result of the analysis with that of the simulation, we found that the sliding F-actin has a flexible and compliant nature.