Evidence for ~e~b~ne-sedated Control of Differe~~tion during Embry~enesis of Vol Vox Carteri

In the preceding paper [l] a model was proposed which offers an explanation to many aspects of embryogenesis in volvox. In particular, the model explains pattern formation during embryogenesis, i.e., it correctly predicts the very regular positioning of the reproductive cells (gonidia) within the Volvox spheroids. The assumption was made that membrane proteins mediating cell-cell contacts are involved in this control. In order to support this assumption experimentally, we treated synchronously developing gonidia with several substances known to modify cell surfaces. It is demonstrated here that these substances strongly disturb the developmental program if applied during the early stages of embryogenesis. Treatment at other times does not affect the developmental program.