CALCIUM-ION REGULATION OF CHIRALITY OF BEATING FLAGELLUM OF REACTIVATED SEA-URCHIN SPERMATOZOA

Near an interface, sea urchin spermatozoa swim almost in circles. The direction is usually clockwise at the lower surface of a coverslip and counterclockwise at the upper surface of a glass slide, when viewed f rom above. Examination of demembranated spermatozoa has shown that Ca2 + regulates the direction of the circular motion of spermatozoa reacti vated with adenosine triphosphate (ATP). This finding suggests that Ca 2+ changes the chirality of the three-dimensional bending waves of spe rm flagella.