title: Changes in the composition of acid extracts of purified Echinus nuclei during cleavage stages and from early embryos.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000818:Animals; D002454:Cell Differentiation; D002467:Cell Nucleus / Q000032:analysis*; D003545:Cysteine / Q000032:analysis
chemical_list: D000596:Amino Acids; D003545:Cysteine