THE DISTRIBUTION OF PHOSPHOARGININE AND PHOSPHOCREATINE IN MARINE INVERTEBRATES

¹ Marine Biological Laboratory, Woods Hole, Massachusetts and the University of Miami School of Medicine, Miami, Florida 33152

1. The arginine, creatine, and related phosphagen content was determined in muscle-containing tissues of nine species of echinoderms, from four subphyla, and in one species of hemichordate. Similar determinations were made on the unfertilized ova of the starfish, Asterias forbesi, and of the two urchins, Arbacia punctata and Lytechinus variegatus.

2. Both phosphoarginine and phosphocreatine occur in moderate to large amounts in the longitudinal muscles of Thyone briareus and of Ludwigthuria floridana. Both phosphagens occur in light to moderate amounts in the rays of the starfish, Asterias forbesi, Asterias vulgaris and Echinaster sentus, with light amounts of phosphoarginine and large amounts of creatine phosphate in the rays of the starfish, Echinaster spinulosa, and of the brittle star, Ophioderma brevispina.

3. Light amounts of phosphoarginine and large amounts of phosphocreatine were also found in the lantern protractors of Arbacia punctata.

4. Light amounts of both phosphagens were found in total body homogenates of the hemichordate, Saccoglossus kowalevskii.

5. While both phosphoarginine and phosphocreatine are lacking in the unfertilized ova of A. forbesi, light amounts of both phosphagens are present in the ova of L. variegatus and trace amounts of both in the ova of A. punctata.

6. The data obtained fail to confirm (1) the early concept that invertebrates are "acreatinate" and (2) that differential distribution of the phosphagens, as such, can be employed as a criterion for confirming the possible phylogenetic relationship between the echinoderms and primitive chordates.