Isolation and identification of a specific and reversible inhibitor of starfish development

An inhibitor of development of the starfish Asterina pectinifera was purified to homogeneity from a culture of the bacterium Bacillus subtilis, and was identified as adenosine. Adenosine at 6 μg/ml was shown to halt embryonic development specifically at the 256-cell stage when all the embryonic cells differentiate into epithelial cells. By returning treated embryos to normal seawater, they developed normally to the bipinnaria stage.