Cleavage and blastoderm formation in normal and experimentally deformed naked eggs of a dipteran insect

From egg to pole cells: Ultrastructural aspects of early cleavage and germ cell determination in insects

“…In the latter, no cytaster has been found so far, but during periods of interphase, microtubules are very numerous throughout the cleaving egg (Junquera, 1985). Such tests revealed that colchicine and vinblastine blocked cleaving eggs in metaphase stage, while cytochalasin B did not affect the process of cleavage.…”

“…Several drugs known to interact with cytoskeletal elements have been used in Drosophila (Foe and Alberts, 1983;Kellogg et al, 1988;Zalokar and Erk, 19761, in the nonpaedogenetic gall midge Wachtliella (Wolf, 19781, and in the paedogenetically reproducing gall midge Heteropeza (Kaiser and Went, 1987). In the latter, no cytaster has been found so far, but during periods of interphase, microtubules are very numerous throughout the cleaving egg (Junquera, 1985). Such tests revealed that colchicine and vinblastine blocked cleaving eggs in metaphase stage, while cytochalasin B did not affect the process of cleavage.…”

“…In Heteropeza, however, elements of Golgi-apparatus and ER frequently appear in close association with the cleavage furrow and nuclear envelopes; moreover, their number increases during cleavage stages. Therefore Junquera (1985) suggests that they play a dominant role in membrane production. Beyond that, in the cytoplasm of preblastoderm stages of Heteropeza, staror rosette-shaped configurations (section entitled Egg Cell) are observed (Junquera, 1985), as are known to exist for newly laid eggs as well as blastoderm and pole cells in Smittia (Figs.…”

“…Therefore Junquera (1985) suggests that they play a dominant role in membrane production. Beyond that, in the cytoplasm of preblastoderm stages of Heteropeza, staror rosette-shaped configurations (section entitled Egg Cell) are observed (Junquera, 1985), as are known to exist for newly laid eggs as well as blastoderm and pole cells in Smittia (Figs. 22 and 23) and Nasonia (Zissler and Sander, 1982).…”

“…Moreover, these studies have been frequently restricted to certain selected egg regions (for review see Zissler and Sander, 1982). Attempts at analyzing the entire cytoarchitecture of the newly laid egg and the early developmental stages (i.e., cleavage to early blastoderm) by TEM have been made so far in certain species of the fruitfly, Drosophila (Engstrom et al, 1982;Fullilove and Jacobson, 1971;Fullilove et al, 1978;Hay et al, 1988a;Kobayashi and Okada, 1989;Mahowald, 1962Mahowald, , 1963aMahowald, ,b, 1968Mahowald, , 1971aMahowald et al, 1976Mahowald et al, , 1979aMahowald et al, ,b, 1981Mahowald et al, , 1983Okada, 1986;Okada and Kobayashi, 1987;Okada and Waddington, 1959;Sanders, 1975;Swanson and Poodry, 1980;Ueda and Okada, 19821, in the cecidomyiide gall midge, Heteropeza pygmaea (Fux, 1975;Junquera, 1983Junquera, , 1985Kaiser and Went, 1987;Meats and Tucker, 1976), in the chironomid midge, Smittia spec. (Zissler, 1987;Zissler and Sander, 1973, 1977 and in the domesticated silkmoth, Bombyx mori (Miya, 1978(Miya, , 1984(Miya, , 1985Takesue, 1985;Takesue and Keino, 1982;Takesue et al, 1985).…”