ISSN:
1432-041X
Keywords:
Yolk sac
;
Ultrastructure
;
Embryogenesis
;
Drosophila
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Changes at the ultrastructural level during germ band extension in the embryo ofDrosophila melanogaster are described. Cytoplasmic connections between cells and the yolk sac are present during initial cellular movements. At this time, a continuous system of microfilaments is present adjacent to the membranes in the connections and at the periphery of the yolk sac. As germ band extension progresses, this system becomes discontinuous, and microfilaments are apparent only in the immediate vicinity of the connections. Cytoplasmic connections are disassembled at approximately the midpoint of extension; at the same time, extensive membrane associations develop between germ band cells and between these cells and adjacent yolk sac membranes. Positioning and orientation of cytoplasmic connections suggest that the yolk sac, via these connections, is actively involved in the cellular movements of early germ band extension.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00849045
