Photolysis of caged calcium in cilia induces ciliary reversal in Paramecium caudatum

Microtubule sliding was induced in axonemes obtained from isolated cilia of Paramecium caudatum when they were exposed to a reactivating solution containing ATP after mild treatment with trypsin. Over a very wide range of concentrations (1 nM-4 mM), Ca2+ in the reactivating solution had no effect on the proportion of axonemes that disintegrated as the result of microtubule sliding. Also, the velocity of sliding, determined by cinematography, and the polarity of the direction of sliding-force generation, determined by electron microscopy with regards to the base-to-tip axis of the cilium, were not affected by Ca2+. The results indicate that the Ca sensitivity, which is responsible for the ciliary reversal response, was removed from the axoneme, possibly as the result of trypsin treatment. It is thus unlikely that Ca sensitivity is attributable to the basic sliding machinery that powers ciliary movement.

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Binding of Ca Ions by Paramecium caudatum

The Journal of General Physiology ◽

10.1085/jgp.50.5.1303 ◽

1967 ◽

Vol 50 (5) ◽

pp. 1303-1310 ◽

Cited By ~ 25

Author(s):

Yutaka Naitoh ◽

Ikuo Yasumasu

Keyword(s):

Binding Sites ◽

Calcium Uptake ◽

Mass Action ◽

Paramecium Caudatum ◽

Law Of Mass Action ◽

Exchange System ◽

External Application ◽

Ciliary Reversal ◽

Ca Ions ◽

Competing Ions

Binding of 45Ca by live Paramecium caudatum was determined under various external ionic conditions. It was found that calcium uptake was separable into at least two components, a rapid and a slow one. The rapid component was influenced by the presence of certain other ions in a manner which agrees with the law of mass action. It appears that an ion exchange system may be involved in a binding equilibrium established between Paramecium, Ca++, and certain other ions. K+, Rb+, and Ba++ in the equilibrium medium are among those ions which inhibit calcium uptake. It is proposed that liberation of Ca++ from binding sites on Paramecium by an exchange reaction with competing ions is the first step in the mechanism of ciliary reversal in the response to external application of these ions.

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Ionic Control of the Reversal Response of Cilia in Paramecium caudatum

The Journal of General Physiology ◽

10.1085/jgp.51.1.85 ◽

1968 ◽

Vol 51 (1) ◽

pp. 85-103 ◽

Cited By ~ 85

Author(s):

Yutaka Naitoh

Keyword(s):

Cation Exchange ◽

Calcium Ions ◽

Time Course ◽

Calcium Release ◽

Published Data ◽

Paramecium Caudatum ◽

Exchange System ◽

Contractile System ◽

Ciliary Reversal ◽

Final Amount

The duration of ciliary reversal of Paramecium caudatum in response to changes in external ionic factors was determined with various ionic compositions of both equilibration and stimulation media. The reversal response was found to occur when calcium ions bound by an inferred cellular cation exchange system were liberated in exchange for externally applied cations other than calcium. Factors which affect the duration of the response were (a) initial amount of calcium bound by the cation exchange system, (b) final amount of calcium bound by the system after equilibration with the stimulation medium, and (c) concentration of calcium ions in the stimulation medium. An empirical equation is presented which relates the duration of the response to these three factors. On the basis of these and previously published data, the following hypothesis is proposed for the mechanism underlying ciliary reversal in response to cationic stimulation: Ca++ liberated from the cellular cation exchange system activates a contractile system which is energized by ATP. Contraction of this component results in the reversal of effective beat direction of cilia by a mechanism not yet understood. The duration of reversal in live paramecia is related to the time course of bound calcium release.

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Control of the Orientation of Cilia by Adenosinetriphosphate, Calcium, and Zinc in Glycerol-Extracted Paramecium caudatum

The Journal of General Physiology ◽

10.1085/jgp.53.5.517 ◽

1969 ◽

Vol 53 (5) ◽

pp. 517-529 ◽

Cited By ~ 26

Author(s):

Yutaka Naitoh

Keyword(s):

Calcium Ions ◽

Cation Exchanger ◽

Maximum Response ◽

Paramecium Caudatum ◽

Ciliary Reversal ◽

Predominant Orientation

The predominant orientation of cilia in glycerol-extracted Paramecium is toward the posterior of the specimen in a KCl solution. The cilia became reoriented toward the anterior shortly after transfer of the extracted cell to a mixture of ATP, calcium, and zinc. The degree of response was graded as a function of the concentration of each of the three essential factors. Minimum concentrations for the maximum response were 0.2 mM in ATP, 0.8 mM in calcium, and 0.0002 mM in zinc. The observations support the hypothesis that cation-induced ciliary reversal in live specimens is initiated by calcium ions which become displaced from an inferred cellular cation exchanger system.

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Effects of ionophore A23187 on ciliary activity of Paramecium caudatum

Canadian Journal of Microbiology ◽

10.1139/m88-032 ◽

1988 ◽

Vol 34 (2) ◽

pp. 169-179 ◽

Cited By ~ 1

Author(s):

Michael J. Doughty

Keyword(s):

Extracellular Calcium ◽

Ion Concentration ◽

Ciliary Activity ◽

Ionophore A23187 ◽

Dependent Manner ◽

Paramecium Caudatum ◽

Alkaline Ph ◽

Ph Values ◽

Swimming Motion ◽

Ciliary Reversal

The ciliated protozoan Paramecium caudatum (suspended in buffered solutions of pH 4.5–9.5) was treated with the ionophore A23187. With calcium and sodium as the only added extracellular cations, A23187 stopped ciliary motion and immobilized the cells. The rate of immobilization increased as a function of A23187 concentration (0.5–16 μg/mL) and extracellular calcium concentration (0.016–4 mM), but decreased as a function of increasing extracellular pH. The rate of immobilization was markedly sensitive to the extracellular calcium ion concentration at alkaline pH, but showed only slight calcium sensitivity at acid pH values. Continuous ciliary reversal (and thus backward swimming motion of the cells) was not observed under these conditions. However, extracellular magnesium ions (in a concentration-dependent manner) attenuated and even prevented the immobilization induced by calcium–A23187 treatment. In addition, in the presence of 1 mM Mg2+, a periodic ciliary reversal response was induced by calcium–A23187 treatment. At neutral pH values, the duration of this response increased as a function of extracellular calcium, but not magnesium, ion concentration. At neutral to alkaline pH values, a sustained slow backward swimming or circling motion (partial ciliary reversal) occurred after the period of periodic ciliary reversal.

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Role of the Cilia Membrane in Control of Microtubule Sliding

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600002683 ◽

1980 ◽

Vol 38 ◽

pp. 612-615

Author(s):

Edna S. Kaneshiro

Keyword(s):

Control Mechanism ◽

Beat Frequency ◽

Surface Membrane ◽

Ciliary Membrane ◽

Ciliary Beating ◽

Ciliary Reversal ◽

Voltage Dependent ◽

Reversal Mechanism ◽

And Function

It is currently believed that ciliary beating results from microtubule sliding which is restricted in regions to cause bending. Cilia beat can be modified to bring about changes in beat frequency, cessation of beat and reversal in beat direction. In ciliated protozoans these modifications which determine swimming behavior have been shown to be related to intracellular (intraciliary) Ca2+ concentrations. The Ca2+ levels are in turn governed by the surface ciliary membrane which exhibits increased Ca2+ conductance (permeability) in response to depolarization. Mutants with altered behaviors have been isolated. Pawn mutants fail to exhibit reversal of the effective stroke of ciliary beat and therefore cannot swim backward. They lack the increased inward Ca2+ current in response to depolarizing stimuli. Both normal and pawn Paramecium made leaky to Ca2+ by Triton extrac¬tion of the surface membrane exhibit backward swimming only in reactivating solutions containing greater than IO-6 M Ca2+ Thus in pawns the ciliary reversal mechanism itself is left operational and only the control mechanism at the membrane is affected. The topographic location of voltage-dependent Ca2+ channels has been identified as a component of the ciliary mem¬brane since the inward Ca2+ conductance response is eliminated by deciliation and the return of the response occurs during cilia regeneration. Since the ciliary membrane has been impli¬cated in the control of Ca2+ levels in the cilium and therefore is the site of at least one kind of control of microtubule sliding, we have focused our attention on understanding the structure and function of the membrane.

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