Energetics of ciliary movement in Sabellaria and Mytilus.

Abstract

ABSTRACT High-speed cinephotography has been used to study the movements performed by compound cilia from the segmental gills of Sabellaria and from the abfrontal face of the gill filaments of Mytilus. The two types of cilium have distinctly different beat patterns. Equations are derived which allow the calculation of the energy necessary to overcome viscous resistance during the effective and recovery strokes of a cilium in terms of its dimensions and angular frequency. In Sabellaria cilia the energy needed to overcome viscous forces is greater for the effective stroke than for the recovery stroke, but the reverse is true for Mytilus abfrontal cilia. Estimates of the work done to overcome elastic forces are probably too high, but it appears that the elastic work done in the recovery stroke is greater than that in the effective stroke for cilia of both types if the stiffness remains constant throughout the beat. The energy released if each fibrillar arm causes the breakdown of one ATP molecule per beat cycle is greater than that required to overcome viscous resistance to ciliary motion.