Analysis of the vegetalizing action of tyrosine on the sea urchin embryo

Abstract

Vegetalization was produced in sea urchin embryos by treatment with D-and L-p-tyrosine, *tyrosine, and m-tyrosine, for 2 to 6 hours during cleavage. Glycine was without effect on development; phenylalanine produced general effects represented by reduction of both animal and vegetal structures. The vegetalizing action of tyrosine was synergistic with that of lithium or dinihophenol. However, unlike the latter compounds, tyrosine had no effect on respiratory rate of the embryos.The uptake and the incorporation of algal hydrolysate-C-14 and leucine-C-14, added to the sea water medium, were lower in sea urchin embryos in the presence of tyrosine or phenylalanine than in untreated control embryos. Inhibition of incorporation caused by phenylalanine was about twice that by tyrosine, and it was postulated that the different effects of these substances on development are related to the degree of inhibition. Neither glycine nor lithium inhibited amino acid uptake.When embryos were treated with tyrosine in the presence of a full complement of those free amino acids normally found in the egg, the vegetalizing effect of tyrosine was annulled. Since the sea urchin depends upon endogenous amino acids for protein synthesis during cleavage, it is suggested that in some way tyrosine limits the endogenous supply of amino acids available for synthesis of the proteins associated with animal structures by inhibiting their release from storage protein.

Gene Dependency of Vegetalization in Sea Urchin Embryos Treated With Lithium

“…When lithium substitutes for potassium the amino acid incorporation is very low. Mastrangelo (1965) found, however, no effect on the amino acid incorporation in whole embryos subjected to vegetalizing concentrations of lithium.…”

“…This obvious approach to normal development demonstrates that gene activation and transfer of genetical information is a necessary link in the vegetalizing action of lithium. A weak effect of lithium reveals itself as a defective differentiation of the oral lobe (Runnstrom, 1928;Mastrangelo, 1965). This indicates that lithium affects primarily the animal anabolic pathways.…”

Developmental Modifications in Arbacia Punctulata by Various Metabolic Substances

“…Since the cobalt effect is produced with equal facility by cobalt chloride and cobalt glycine, the effectiveness of the cobalt ion, rather than the glycine moiety, is clear. According to Mastrangelo (1966) glycine does not have any effect on the development of various echinoids. Rulon (1956) had noted that there was a lack of cohesiveness in the cobalttreated Dendraster embryos.…”

Cell Contact Reformation of Dissociated Cells From Embryonic Cells of Strongylocentrotus Purpuratus

“…Earlier work [4,5,131 indicated that cell migration played a role during the segregation of cells during the reformation of quasinormal embryos from disaggregated cells, as predicted by the differential adhesion hypothesis [ 151. Since the differential adhesion hypothesis not only involves cell migration but also cell adhesion, the study of sea urchin embryonic selfreassembly would be incomplete without an investigation of cell contact formation during cell migration.…”