Myogenesis in primary cell cultures from larvae of the abalone, Haliotis rufescens.

Myogenesis culminating in the differentiation of contracting myocytes occurs in primary cell cultures derived from premyogenic trochophore and early veliger larvae of Haliotis rufescens (red abalone, gastropod mollusc). No detectable muscle cells were present at the start of the primary cultures. Onset and organization of myofibrillogenesis in culture (revealed by histochemical and immunohistochemical detection of filamentous actin, myosin, and desmin) generally paralleled those of smooth muscle development in vivo, although development of cells with striated sarcomeres was occasionally observed in culture, but not in the intact larvae. Most of the muscle cells that developed in culture were mononucleate, although some multinucleate syncytia were observed. Dissociated larval cells remained viable up to 12 weeks, exhibiting an average of one to two divisions in the first six days, and attachment of approximately 6 to 8% of the original population. Cell culture and in vitro myogenesis of Haliotis myoblasts and myocytes will facilitate studies of the molecular mechanisms controlling early muscle development, and should provide a useful model system for biotechnological improvement of the abalone.