Intercellular bridges in the embryo of the Atlantic squid, Loligo pealei. II: Formation of the bridge

Incomplete cytokinesis followed by the disappearance of the midbody and spindle remnant results in intercellular bridges between the cells of the blastoderm of the squid embryo. An electron microscope study of the morphology of the stages of development of the intercellular bridge is presented. Cyto...

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Published inCell motility (New York, N.Y.) Vol. 1; no. 4; p. 455
Main Authors Cartwright, Jr, J, Arnold, J M
Format Journal Article
LanguageEnglish
Published United States 1981
Subjects
Animals
Cell Communication
Cell Division
Decapodiformes - embryology
Decapodiformes - ultrastructure
Intercellular Junctions - ultrastructure
Intracellular Membranes - ultrastructure
Microtubules - ultrastructure
Mitosis
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Summary:Incomplete cytokinesis followed by the disappearance of the midbody and spindle remnant results in intercellular bridges between the cells of the blastoderm of the squid embryo. An electron microscope study of the morphology of the stages of development of the intercellular bridge is presented. Cytokinesis ceased as the furrow base reached a diameter slightly larger than the midbody. As furrowing stopped, a dense material accumulated to form a cylindrical sheath 50 nm thick, lining the inner surface of the furrow base. Proteolytic enzymes showed this material to have a significant protein component. As the midbody broke down, vesicles lined the inner surface of the bridge sheath. In this configuration, there was cytoplasmic continuity between the cells, and organelles appeared to pass through the bridge. The intercellular bridge could become temporarily closed. Vesicles entered the channel and fused with the vesicles lining the inner surface of the sheath. The vesicles enlarged until the channel became occluded with a series of transverse cisternae, the edges of which were embedded in the material of the sheath. When the bridge reopened, the transverse cisterna appeared to dissociate from the sheath, move out of the channel, and break down. Occasionally bridges were seen in which the bridge wall appeared distorted into lobes. It is suggested that such bridges might be in the process of breaking down, resulting in the final separation of the cells.
ISSN:0271-6585
DOI:10.1002/cm.970010406