Analysis of Sliding Actin Filaments Utilizing a Novel Method of Spatiotemporal Color Patterns

Satoshi Hasegawa^1,2 and Koshin Mihashi²

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

(Received December 24, 1999; Accepted April 19, 2000)

Keywords: Image Processing, Computer Visualization, Pattern, Actin Filament, Motility Assay

Abstract. The study of sliding movements of actin filaments on a surface-fixed myosin in an in vitro motility assay presents a useful method employed to understand the mechanisms of muscle contraction. In order to gain insight into this study, we here propose a novel method to create "spatiotemporal color patterns" of a moving thin filament. First, we verified the method by using artificial patterns generated by computer simulations. Then we gleaned coordinate data of actin filaments from video images by applying digital processing, and expressed the results with the patterns. With this method, the existence of fluctuations in the sliding velocity and/or locus were clearly visualized. As a result, we could also develop a new effective method to accurately determine the sliding velocity of the transforming filaments. In addition, we will discuss the complementarity between the velocity and the length of the filament as they can not be determined simultaneously.