title: Mechanical strength of sarcomere structures of skeletal myofibrils studied by submicromanipulation.
abstract: The mechanical strength of sarcomere structures of skeletal muscle was studied by rupturing single myofibrils of rabbit psoas muscle by submicromanipulation techniques. Microbeads coated with alpha-actinin were attached to the surface of myofibrils immobilized to coverslip. By use of either optical tweezers or atomic force microscope, the attached beads were captured and detached from the myofibrils. During the detachment of the beads, the actin filaments bound specifically to the beads were peeled off from the bulk structures of myofibrils, thus rupturing the peripheral components of the myofibrils bound to the actin filaments. By analyzing the ruptures thus produced in various myofibril preparations, it was found that the sarcomere structure of myofibrils is maintained by numerous molecular components having the mechanical strength sufficient to sustain the contractile force produced by the actomyosin system. The present techniques could be applied to study the mechanical strength of cellular organelles containing actin filaments as their component.
authors.affiliation: Department of Physics (Biophysics Section), Faculty of Science, Tokyo University of Science, Shinjuku-ku, Tokyo 162-8601, Japan.
authors.forename: Taisuke
authors.initials: T
authors.lastname: Kayamori
authors.forename: Norihito
authors.initials: N
authors.lastname: Miyake
authors.forename: Nao
authors.initials: N
authors.lastname: Akiyama
authors.forename: Momoko
authors.initials: M
authors.lastname: Aimi
authors.forename: Jun'ichi
authors.initials: J
authors.lastname: Wakayama
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kunioka
authors.forename: Takenori
authors.initials: T
authors.lastname: Yamada
mesh_terms: D008841:Actin Cytoskeleton / Q000502:physiology / Q000648:ultrastructure; D000185:Actinin; D000818:Animals; D001696:Biomechanical Phenomena; D004591:Electrophoresis, Polyacrylamide Gel; D008846:Micromanipulation / Q000379:methods*; D018625:Microscopy, Atomic Force; D008863:Microspheres; D009119:Muscle Contraction / Q000502:physiology; D009210:Myofibrils / Q000502:physiology* / Q000648:ultrastructure; D016658:Psoas Muscles / Q000502:physiology / Q000648:ultrastructure; D011817:Rabbits; D012518:Sarcomeres / Q000502:physiology* / Q000648:ultrastructure
chemical_list: D000185:Actinin