title: Calcium control of waveform in isolated flagellar axonemes of Chlamydomonas.
abstract: The effect of Ca(++) on the waveform of reactivated, isolated axonemes of chlamydomonas flagella was investigated. Flagella were detached and isolated by the dibucaine procedure and demembranated by treatment with the detergent Nonidet; the resulting axomenes lack the flagellar membrane and basal bodies. In Ca(++)-buffered reactivation solutions containing 10(-6) M or less free Ca(++), the axonemes beat with a highly asymmetrical, predominantly planar waveform that closely resembled that of in situ flagella of forward swimming cells. In solutions containing 10(-4) M Ca(++), the axonemes beat with a symmetrical waveform that was very similar to that of in situ flagella during backward swimming. In 10(-5) M Ca(++), the axonemes were predominantly quiescent, a state that appears to be closely associated with changes in axomenal waveform or direction of beat in many organisms. Experiments in which the concentrations of free Ca(++), not CaATP(--) complex were independently varied suggested that free Ca(++), not CaATP(--), was responsible for the observed changes. Analysis of the flagellar ATPases associated with the isolated axonemes and the nonidet- soluble membrane-matrix fraction obtained during preparation of the axonemes showed that the axonemes lacked the 3.0S Ca(++)-activated ATPase, almost all of which was recovered in the membrane-matrix fraction. These results indicate that free Ca(++) binds directly to an axonemal component to alter flagellar waveform, and that neither the 3.0S CaATPase nor the basal bodies are directly involved in this change.
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology*; D002462:Cell Membrane / Q000502:physiology; D002474:Cell-Free System; D002696:Chlamydomonas / Q000502:physiology / Q000648:ultrastructure*; D004398:Dyneins / Q000378:metabolism; D005407:Flagella / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D008870:Microtubules / Q000502:physiology*; D009068:Movement
chemical_list: D000251:Adenosine Triphosphatases; D004398:Dyneins; D002118:Calcium