Uptake of dissolved amino acids by embryos and larvae of Dendraster excentricus (Eschscholtz) (Echinodermata: Echinoidea)

Abstract

The uptake of 14C- and 3H-labelled mixed amino acids by embryos and larvae of Dendraster excentricus (Eschscholtz) was investigated using liquid scintillation counting and autoradiography. Peaks in transport were observed immediately after fertilization, at the mesenchyme blastula stage, and at the early gastrula stage. The subsequent linear increase in amino acid transport correlated with increase in surface area of the growing pluteus. Autoradiographs showed that in all stages epidermis accumulated 3H label more than internal tissues. It was concluded that uptake rate of dissolved amino acids is dependent upon the size and development state of the embryo and independent of the requirement of the larva to feed.