title: Differentiation and growth of myotomal muscles in a non-model tropical fish Pterophyllum scalare (Teleostei: Cichlidae).
abstract: Somite differentiation, muscle fibres formation and growth were analysed in a non-model tropical fish Pterophyllum scalare. In this study, it was found that during somite differentiation, a primary myotome appears. The primary myotome is filled with multinucleated myotubes that constitute the major part of the somite. Subsequently, Pax-3 (paired-box protein)-positive cells, located externally to the myotomes, appear. In post-hatching stages, mononucleated proliferating cell nuclear antigen-positive cells are observed in the inter-myotomal spaces and within the myotomes. The mononucleated cells, situated in the myotomes, first express desmin in their cytoplasm and then Pax-7 (paired-box protein) in their nuclei. Expression of desmin indicates that they will enter myogenic pathway, whereas expression of Pax-7 suggests their role of satellite cells. We assume that mononucleated intramyotomal cells are myogenic precursors involved in muscle growth. In advanced (post-hatching) stages of myogenesis, myotomes contain both primary and new muscle fibres. Morphometric analyses show that in Pterophyllum scalare, growth of muscle fibres is mainly a result of hypertrophy.
authors.affiliation: Department of Animal Developmental Biology, Zoological Institute, University of Wroclaw, Poland.
authors.forename: A
authors.initials: A
authors.lastname: Kacperczyk
authors.forename: I
authors.initials: I
authors.lastname: Jędrzejowska
authors.forename: M
authors.initials: M
authors.lastname: Daczewska
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000502:physiology; D023681:Cichlids / Q000033:anatomy & histology / Q000196:embryology*; D003893:Desmin / Q000096:biosynthesis; D024510:Muscle Development / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000502:physiology; D009132:Muscles / Q000196:embryology*; D051761:Paired Box Transcription Factors / Q000096:biosynthesis; D019170:Somites / Q000196:embryology
chemical_list: D003893:Desmin; D051761:Paired Box Transcription Factors