Active Movement of the Tunic in Halocynthia roretzi

Journal of Biomechanical Science and Engineering

Yoko KATO¹ 

[1] Faculty of Engineering, Tohoku Gakuin University

关键词: Nervous System;    Myocyte;    α-Smooth Muscle Actin;    Elastic Fiber;    Tunic;   

DOI  :  10.1299/jbse.5.163

来源: Japan Society of Mechanical Engineers

【 摘 要 】

References(29)Halocynthia roretzi, a solitary ascidian, can swell and deflate its solid, leather-like tunic largely, but it is not clear whether the tunic deforms actively. Cellulose Iβ, which is predominant in higher plants, is also present in the tunic as a highly crystalline form. The elastic modulus of its whisker crystalline is considerably high. Substantial amounts of chitin sulfate-like, water-soluble polysaccharide were also present. These polysaccharides alone would barely cause tunic deformation. If the tunic's flexible deformation is self-controlled, it would have another element in addition to the polysaccharide, and it would be an ideal model for designing a novel material. The hypothesis of this study was that the H. roretzi tunic has a nervous system, myocytes, and elastic fibers controlling its flexible deformation. Using acetylcholine and touch as stimuli, the tunic samples were found to deform at acetylcholine concentrations ≥20 µM, indicating the existence of a nervous system, and to have mechanosensitivity. The Bodian, Klüver-Barrera, acetylcholinesterase, immunohistochemical (α-smooth muscle actin), and Elastica-Masson staining methods indicated the presence of a nervous system, myocytes, a region rich in α-smooth muscle actin, and elastic fibers, validating the hypothesis. The self-controlled system in the tunic is useful to understand the properties of the tunic and to design a novel actively deforming material.

【 授权许可】

Unknown