[From the ameba to the pulsating heart: evolution and fine structure of the intracellular movement apparatus (author's transl)].

Different kinds of cell motility are reviewed in this paper with special regard to development and ultrastructure. The variety of animal cell motility types can be reduced to three principles : ciliary and ameboid movements and muscle contraction. The ultrastructure of all kinds of cilia is very similar from single cell organisms to highly specialized cells of the human body e.g., ciliary respiratory epithelium. As a rule, ciliary movement is caused by minimal sliding of the nine double tubules consisting of tubulin, a protein differing from myosin and actin. Ameboid movement and muscle cell contraction are based on the sliding filament mechanism of actin and myosin. Although the principles of this mechanism have not changed during evolution some differences in the structure and arrangement of actin and myosin filaments occurred. Obviously, the high degree of order of the myofibrils of vertebrate heart and skeletal muscle cells has developed from loose and rapid changing arrangement of contractile filaments in ameboid cells. There are some changes of residues in the actin and myosin molecules during the development of the intracellular contractile system. Finally, some peculiarities of the myocardium, its special arrangement of muscle cells and some disturbances of the contractile filaments under pathologic conditions are discussed.