Search results

1

The origin of syncytial muscle fibres in the myotomes of Xenopus laevis ? a revision

100%

Kielbowna L., Daczewska M.

|

issue 1-2

39-44

EN

During the early stages of myogenesis in X. laevis, the primary myoblasts (of mesodermal origin) differentiate simultaneously, in each myotome, into mononucleate myotubes. At later stages mesenchymal cells appear in intermyotomal fissures and then in the myotomes between myotubes and contribute to the formation of syncytial muscle fibres. The pathway of mesenchymals cell during myogenesis was described in X. laevis by monitoring the incorporation of 3H-thymidine. 3H-thymidine was incorporated in the nuclei of mesenchymal cells in intermyotomal fissures of younger myotomes and then in those of older myotomes between the myotubes revealing the proliferation of mesenchymal cells. As expected, nuclei of differentiating mononucleate myotubes did not incorporate 3H-thymidine. At later stages of myogenesis the myotubes were found to contain two classes of nuclei: large nuclei of the primary myoblasts (of myotomal origin) and smaller nuclei originating from secondary myoblasts of mesenchymal origin. TEM and autoradiographic analyses confirm that mulinucleate myotubes in X. laevis arise through fusion of secondary myoblasts with mononucleate myotubes.

2

Myotomal myogenesis in Triturus vulgaris L. (Urodela) with special reference to the role of mesenchymal cells

100%

Daczewska M., Kielbowna L.

Folia Biologica

|

2000

|

vol. 48

|

issue 1-2

37-42

EN

Two stages can be distinguished in the differentiation of myotomal muscle fibres in Triturus vulgaris. In the first stage only synchronously differentiating myotomal cells are engaged; in the second stage mesenchymal cells also take part in the process. Myotomal cells (primary myoblasts) fuse to form 2-3 nucleate myotubes. Only in the caudal part of the embryo mononucleate myotubes persist. The mononucleate myotubes, like polynucleate ones, occupy the whole length of the myotome. The differentiation of myotubes is accompanied by vitellolysis. At further development stages mesenchymal cells enter the intermyotomal fissure, after which they migrate to the myotomes, between the myotubes. The cells that remain in the intermyotomal fissures retain their fibroblastic potential (they synthesise collagen). Their daughter cells adjoining the myotubes acquire myogenic abilities. Their myoblastic potential is evidenced by their ability to fuse with the myotube. Fusion of secondary myoblasts (of mesenchymal origin) with the myotube results in further growth of the myotubes. In T. vulgaris myotomal myotubes and muscle fibres developing from them are of myotomal-mesenchymal origin.

3

Myotomal myogenesis of axial muscle in the sturgeon Acipenser baeri (Chondrostei, Acipenseriformes)

100%

Daczewska M., Saczko J.

|

issue 1-2

29-38

EN

Compared to teleost fishes, a unique character of the myogenesis of the plesiomorphic A. baeri is the fusion of myoblasts derived from the somite, leading to the formation of multinucleate muscle lamellae. Then, the lamellae are converted into cylindrical muscle fibres. The mechanism of transformation of lamellae into fibres is still debatable. Early embryonic muscle growth is mainly due to the hypertrophy of somite-cell derived stock. After hatching, hypertrophic growth occurs parallel to hyperplastic growth. Proliferatively active mesenchymal cells, which migrate from the intermyotomal space into the myotomes, participate in both processes.

Refine search results

3 Folia Biologica

2 2005

1 2000

3 Daczewska M.

2 Kielbowna L.

1 Saczko J.

The origin of syncytial muscle fibres in the myotomes of Xenopus laevis ? a revision

Myotomal myogenesis in Triturus vulgaris L. (Urodela) with special reference to the role of mesenchymal cells

Myotomal myogenesis of axial muscle in the sturgeon Acipenser baeri (Chondrostei, Acipenseriformes)