Figure 1From: Primary culture of avian embryonic heart forming region cells to study the regulation of vertebrate early heart morphogenesis by vitamin ADevelopment of chicken embryo HFR explant in culture. (A, left) Chicken embryo at 4 ss; (A, right); dissected heart forming region explant from 4–5 ss embryo; (B) 4–5 ss heart forming region explant after one day of cultivation in Endo-Grow medium. Red lines mark the borders of contractile tissue developed within a day in culture (see Additional file 1). Contractile tissues were observed by microscopy and documented using video camera. hfr, heart forming region; ss, somite stage. Scale bars, 1 mm.Back to article page