Oogenesis of Diadegma semiclausum (Hymenoptera: Ichneumonidae) and its associated polydnavirus.
We present a detailed ultrastructural analysis of ovary and calyx cell differentiation of Diadegma semiclausum. Numerous gametangia in various developmental stages were examined with electron microscopy to characterize the ultrastructure features of oogenesis, the most important of which is the development of nurse cells. In the germarium, the undifferentiated germ cells diversify, and one of the central cells of the cluster differentiates into an oocyte while the remaining become nurse cells. Germ cells continue developing in the vitellarium until mature and then enter into the calyx region. The calyx epithelium contains typical ichneumonid polydnaviruses with the following characteristics: (1) the virus particles assemble in the nuclei of calyx cells where they acquire an initial (inner) membrane, then migrate through the cytoplasm and budd out into the lumen of the ovary, at which time they acquire a second envelope (outer membrane); (2) the particle has a genome comprising several DNA segments. However, this new polydnavirus (Diadegma semiclausum polydnavirus) in the genus ichnovirus was not attached to the surface of the egg chorion.
Huang
Fang
F
Institute of Insect Sciences, Zhejiang University, Hangzhou 310029, China.
Shi
Min
M
Chen
Ya-Feng
YF
Cao
Ting-Ting
TT
Chen
Xue-Xin
XX
D000818:Animals; D002454:Cell Differentiation; D005260:Female; D006927:Hymenoptera / Q000821:virology; D008854:Microscopy, Electron / Q000379:methods*; D009866:Oogenesis / Q000502:physiology*; D010053:Ovary / Q000166:cytology / Q000254:growth & development / Q000648:ultrastructure / Q000821:virology*; D018071:Polydnaviridae / Q000235:genetics / Q000502:physiology*; D014771:Virion / Q000378:metabolism / Q000502:physiology*