Mechanical oscillations at the cellular scale

Active phenomena which involve force generation and motion play a key role in a number of phenomena in living cells such as cell motility, muscle cont raction and the active transport of material and organelles. Here we discus s mechanical oscillations generated by active systems in cells. Examples ar e oscillatory regimes in muscles, the periodic beating of axonemal cilia an d flagella and spontaneous oscillations of auditory hair cells which play a role in active amplification of weak sounds in hearing. As a prototype sys tem for oscillation generation by proteins, we discuss a general mechanism by which many coupled active elements such as motor molecules can generate oscillations. (C) 2001 Academie des sciences/Editions scientifiques et medi cales Elsevier SAS.