Abstract
Observations of fixed parenchyma cells using electron microscopy were carried out in an attempt to understand the morphogenetic process of blastema formation in regenerating planarians. Fixed parenchyma cells could be found throughout one-day blastemata. In the mid-blastema region where migrating regenerative cells build up a compact cell aggregate, long and slender cytoplasmic processes of the fixed parenchyma cells were seen occupying spaces among regenerative cells. A characteristic feature of such processes was orderly arranged microtubules. Ruthenium red staining revealed thickened portions of cell coats on these processes and occasional formation of gap junctions between the cytoplasmic process of the fixed parenchyma cell and the regenerative cell undergoing migration. Colchicine treatment (M/1,000) caused detachment of the cytoplasmic processes from the regenerative cells. Microtubules within such processes became depolymerized. As a result, directional migration of regenerative cells was inhibited by colchicine treatment. To determine the extracellular site of fibronectin, immunoelectron microscopy was performed in one-day blastema. Immunogold labeling was detected at the surface area of fixed parenchyma cells and regenerative cells. In particular the reactivity was conspicuous at the cytoplasmic process of the fixed parenchyma cells. These observations suggest that the cytoplasmic processes of fixed parenchyma cell are related to directional movement of regenerative cells by providing a contact guidance system. The biological implications of this system are discussed in relation to the extracellular matrix components.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
More From: The International Journal of Developmental Biology
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.