title: Enhanced reappearance of fast fibers in regenerating crayfish claw closer muscles.
abstract: In the pristine claws of adult crayfish the muscle fibers of the closer are all of slow type as judged by sarcomere lengths of greater than 6 micron, and a uniform degree of myofibrillar ATPase activity. In regenerating claws of mature and immature crayfish, the muscle has a central band of fast type fibers as characterized by shorter sarcomeres (less than 6 micron) and a higher degree of ATPase activity than the surrounding slow fibers. During primary development, the closer muscle has a fiber composition similar to that of the regenerating muscle except for a smaller proportion of fast fibers. Thus the reappearance of fast fibers during regeneration recapitulates ontogeny while their enhanced proportions may reflect epigenetic influences such as restriction of nerve-mediated muscle activity in the limb bud.
authors.forename: C K
authors.initials: CK
authors.lastname: Govind
authors.forename: J
authors.initials: J
authors.lastname: Pearce
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D003400:Astacoidea / Q000033:anatomy & histology / Q000502:physiology*; D005121:Extremities / Q000502:physiology; D009132:Muscles / Q000166:cytology / Q000502:physiology*; D012038:Regeneration
chemical_list: D000251:Adenosine Triphosphatases