Fig. 1From: Successful transplantation of spermatogonial stem cells into the seminiferous tubules of busulfan-treated miceExpansion of different testicular cell types on the feeder layer. Bright field photo of the two cell type colonies. Two distinct types of differentiated and undifferentiated cells are obviously shown. Undifferentiated SSCs grow in more compact assemblies in comparison to more loosely connected differentiated SSCsBack to article page