Ca2+-induced tension development in the stalks of glycerinated Vorticella convallaria

Yasushige Moriyama, Kenji Yasuda, Shin'ichi Ishiwata, Hiroshi Asai

    Research output: Contribution to journalArticle

    15 Citations (Scopus)

    Abstract

    We have developed a method of measuring the isometric tension in glycerinated stalks of Vorticella convallaria. Using this method, we measured tension vs. pCa relations in glycerinated V. convallaria stalks. The maximum isometric tension was 4 x 10-8 N on average. The Hill's parameter, n, which is the number of calcium ions bound simultaneously and cooperatively to a contractile element (a force generating element), is approximately 3.2 when the Ca2+ concentration is increased and 2.5 when it is decreased. In order to estimate the efficiency of the energy conversion of Ca2+ binding to mechanical work, we measured the Ca2+-induced Carnot cycle in the Vorticella stalk. The energy efficiency was tentatively estimated to be about 7%. With this method, we have also succeeded in measuring the isometric tension of isolated spasmoneme, the rubber-like contractile fibrous organelle in the stalk. The maximum tension of spasmoneme was approximately one tenth that of the glycerinated stalk. We speculate that the isolated spasmoneme was only partially functional due to damage sustained when it was pulled out of the stalk.

    Original languageEnglish
    Pages (from-to)271-278
    Number of pages8
    JournalCell Motility and the Cytoskeleton
    Volume34
    Issue number4
    DOIs
    Publication statusPublished - 1996

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    Convallaria
    Rubber
    Organelles
    Ions
    Calcium

    Keywords

    • calcium ion
    • energy efficiency
    • Hill's parameter
    • spasmoneme

    ASJC Scopus subject areas

    • Cell Biology

    Cite this

    Ca2+-induced tension development in the stalks of glycerinated Vorticella convallaria. / Moriyama, Yasushige; Yasuda, Kenji; Ishiwata, Shin'ichi; Asai, Hiroshi.

    In: Cell Motility and the Cytoskeleton, Vol. 34, No. 4, 1996, p. 271-278.

    Research output: Contribution to journalArticle

    Moriyama, Yasushige ; Yasuda, Kenji ; Ishiwata, Shin'ichi ; Asai, Hiroshi. / Ca2+-induced tension development in the stalks of glycerinated Vorticella convallaria. In: Cell Motility and the Cytoskeleton. 1996 ; Vol. 34, No. 4. pp. 271-278.
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