The onset of collagen synthesis in sea urchin embryos.

In Arbacia punctulata and Strongylocentrotus purpuratus, two species of sea urchins, collagen synthesis begins during gastrulation and increases many-fold before reaching a plateau in the late pluteus stage. A collagen extraction method involving treatment with 0.1 M NaOH and hot 10% trichloroacetic acid provided the basis for a sensitive assay of collagen synthesis.