Myofiber death plays a role in determining fiber type composition in the claw closer muscles of the snapping shrimp, Alpheus heterochelis

Abstract

AbstractMarine shrimp of the genus Alpheus exhibit a remarkable reversal of asymmetry in their great claws. This unique phenomenon includes transition of the closer muscle in one claw from a muscle of mixed fiber type into a homogenous slow muscle. We have developed monoclonal antibodies that specifically recognize fast and slow myosin heavy chain (MHC), and have used these as immunohistochemical markers to follow the fate of different myofiber types during this transformation. This analysis reveals a strikingly specific necrosis of the fast fibers. The onset of fiber degeneration appears linked to the molt cycle and occurs rapidly once started. This represents the first example of programmed myofiber death as a mechanism used in crustacean muscle development.