This review paper revisits selected Japanese papers on the stalk contraction and relaxation of Vorticellidae. Vorticella, Carchesium and Zoothamnium have stalks that contract very fast powered by binding of calcium ions, and their stalks have the contractile organelle (spasmoneme) that includes nanoscale filaments and spasmin (the major calcium binding protein) in common. The stalk contraction of these Vorticellidae has been studied long for their ultrafast contraction, unique energy source, and potential for bioinspired actuators. In particular, a significant amount of research has been conducted by Japanese researchers for about a century. Although many of those studies were published in English and can be accessed by researchers around the world, some papers received very limited attention despite their valuable findings and insights because they were written in Japanese. To make the key findings of such Japanese papers readily available, they are revisited and reviewed in this review paper. Papers on the stalk contraction and relaxation of Vorticella, Carchesium and Zoothamnium were found via J-STAGE, CiNii and Google Scholar, and six papers published between 1931 and 2006 were chosen, translated, and reviewed for their findings and insights on the biomechanical aspects of stalk contraction and relaxation. Also, chosen figures from the papers were re-worked for better readability, and selected data were analyzed further. Revisiting these Japanese papers is meaningful to research communities on biomechanical engineering, bioinspired engineering, and biophysics.
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