Exogut Formation by the Treatment of Sea Urchin Embryos with Ascorbate and alpha-Ketoglutarate. (collagen synthesis/sea urchin embryo/protocollagen hydroxylation/exogut formation)

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Abstract
In sea urchin embryos at the stages from hatch out to the pluteus stage, [14C]proline incorporation into hot trichloroacetic acid (TCA)-extractable proteins occurred during an exposure to [14C]proline for 3 h at 20.degree. C. The rate of [14C]proline incorporation into hot TCA-extractable proteins was higher in gastrulae and plutei than in blastulae. Percentage of [14C]hydroxyproline residue to whole radioactivity of the hot TCA-extractable proteins was quite low at the blastula stage and increased exponentially during further development. Production of [14C]hydroxyproline residue at the blastula stage and at the later stages, was stimulated by ascorbate and .alpha.-ketoglutarate, activators of protocollagen proline hydroxylase and inhibited by .alpha.,.alpha.''-dipyridyl, an inhibitor of this enzyme. Also the enzyme in the embryos probably is not fully activated because of low amounts of activating substances. These suggest that blastulae also have a potency of protocollagen hydroxylation. Blastula kept in sea water containing ascorbateand .alpha.-ketoglutarate became undeveloped embryo with large exogut. Gastrula developed normally to pluteus even in the presence of these compounds. The embryos, kept in sea water containing these compounds from fertilization to hatch out also developed normally. Exogut formation in the embryos treated by these compounds and normal archenteron formation, were inhibited by .alpha.,.alpha.''-dipyridyl.