- 著者
- Junichi Wakayama Yoshihiro Yoshikawa Toshihiro Yasuike Takenori Yamada
- 出版者
- 日本細胞生物学会
- 雑誌
- Cell Structure and Function (ISSN:03867196)
- 巻号頁・発行日
- vol.25, no.6, pp.361-365, 2000 (Released:2001-03-28)
- 参考文献数
- 9
- 被引用文献数
- 6 8
Atomic force microscopic images of single skeletal myofibrils showed periodical broad filamentous bands interspaced with narrow rigid bands corresponding to the sarcomere structures of skeletal muscle (Yoshikawa, Y., Yasuike, T., Yagi, A., and Yamada, T. 1999. Biochem. Biophys. Res. Comm., 256: 13-19). In order to identify the narrow rigid bands, comparative studies were made for intact single myofibrils and those treated with calcium-activated neutral protease by use of atomic force microscopy. It was found that (a) the periodical narrow rigid bands present in intact myofibrils were completely absent in myofibrils treated with calcium-activated neutral protease, and that (b) myofibrils treated with calcium-activated neutral protease were very fragile compared with intact myofibrils. As calcium-activated neutral protease selectively removes Z-bands of myofibrils (Reddy, M. K., Etlinger, J. D., Rabinowitz, M., Fischman, D. A., and Zak, R. 1975. J. Biol. Chem., 250: 4278-4284), these results clearly indicate that (a) the narrow rigid bands are the Z-bands, and that (b) the Z-bands are the essential disc supporting the sarcomere structure of skeletal muscle.
- 著者
- Nao Akiyama Yoshiki Ohnuki Yuki Kunioka Yasutake Saeki Takenori Yamada
- 出版者
- 日本生理学会
- 雑誌
- The Journal of Physiological Sciences (ISSN:18806546)
- 巻号頁・発行日
- vol.56, no.2, pp.145-151, 2006 (Released:2006-07-30)
- 参考文献数
- 28
- 被引用文献数
- 20 35
The transverse stiffness of single myofibrils of skeletal and cardiac muscles was examined by atomic force microscopy. The microscopic images of both skeletal and cardiac myofibrils in a rigor state showed periodical striation patterns separated by Z-bands, which is characteristic of striated muscle fibers. However, sarcomere patterns were hardly distinguishable in the stiffness distributions of the relaxed myofibrils of skeletal and cardiac muscles. Myofibrils in a rigor state were significantly stiff compared with those in a relaxed state, and in each state, cardiac myofibrils were significantly stiffer compared with skeletal myofibrils. By proteolytic digestions of sarcomere components of myofibrils, it was suggested that cardiac myofibrils are laterally stiffer than skeletal myofibrils because Z-bands, connectin (titin) filament networks, and other components of sarcomere structures for the former myofibrils are stronger than those for the latter.