Localization of Atpase in Rotifer Cilia

Considerable da ta have been accumulated on the fine s t ructure of cilia, sperm tails, and flagella (4, 5) bu t the contract i le mechanism in these structures has yet to be elucidated. T he split t ing of phospha te from A T P (8) and the recognit ion of ATPase activity in myosin (2) have been associated wi th muscular contractili ty. A na tura l sequel to these observations was an a t t empt to establish a comparab le association in vibrat i le systems (7, 1, 2). We have found recently (6) tha t at least in the rotifer there is a peculiar or ienta t ion of the per ipheral filaments when viewed in true cross-section. W h e n per ipheral filaments 9 to 4 are sharply out l ined in normal sections, filaments 5 to 8 are disoriented, or the converse may occur. This suggests the possibility tha t while half of the per ipheral filaments is in extension the other hal f is in contract ion. In this study we have a t tempted to de termine whe the r or not ATPase shows a dist r ibut ion consistent with the s t ructural bilateral asymmetry of rotifer cilia.