Scanning electron microscopy of cells from hydroxyurea-arrested blastulae ofXenopus laevis

Summary Cells fromXenopus embryos blocked at the blastula stage by treatment with hydroxyurea have been isolated and cultured in vitro. The morphology of these cells has been compared with that of cells from normal embryos using scanning electron microscopy. Cells from such hydroxyurea-blocked embryos do not show the features, or changes in features, in culture shown by cells from normal embryos.Acknowledgments. We wish to thank Mr C. Veltkamp for his help with the electron microscopy, and Mrs J. Clumpus for technical assistance.