Kinetics of hemangioblast formation in EB culture and characterization of blast cells. A) Kinetics of blast colony (BCs) formation from cells derived from EBs on consecutive days of development. EBs were dispersed to a single-cell suspension and specific number of live cells was seeded in a semisolid medium. Colonies were counted on day 6 of BC culture. Experiment was performed in quadruplicates, and bars represent standard deviation (SD) from the mean. B) Dynamics of hemangioblast-related gene expression in EB differentiation system. Semi-quantitative RT-PCR was performed from RNA samples isolated from EBs picked on consecutive days of development. Input of RNA was normalized according to β-actin gene expression and minimal number of cycles was performed to achieve linearity of reaction. C) Blast colony on day 6 of culture (phase contrast, 100×). D) Blast cells on day 6 of blast culture (Wright-Giemsa stain, 200× light microscopy). E) FACS analysis of day 6 blast cells.