Oocyte and parthenote development in vitro. A) The oocyte (o) development in OSC culture is accompanied by satellite (black arrow) and neuronal (white arrow) cells. Black arrowheads indicate organelles mowing from the satelite cell into the oocyte and white arrowhead indicates neuronal extension. Note ZP staining of fibro-epithelial cells (f) but no expression of ZP proteins at the oocyte surface (red arrowhead). Sperm associate (arrowheads) with fibroepithelial cells (B) but not with the oocytes (C). D and E) The parthenote shows a trophectoderm (te), blastocoele (bc), and inner cell mass (icm). (A) shows staining for ZP proteins, (B, C and D) are live cultures in phase contrast (PhC), (E) is a DAPI staining of the fixed culture. Adapted from , © Cambridge University Press, and unpublished observations.