Free amino acids in the shrimp crangon crangon and their osmoregulatory significance

Abstract

Measurements of the concentrations of ninhydrin positive substance () and of the individual free amino acids in muscle and haemolymph of Crangon crangon, adapted to various salinities at different temperatures, are recorded, and their significance as osmotic effectors is evaluated.

The pattern of regulation in muscle under various environmental conditions being strictly analogous with that of the haemolymph osmotic regulation, illustrates its importance to the osmotic adjustment of the cells in response to changes in environmental conditions. The salinity-induced variation in in turn reflects the total concentrations of the 3 most abundant amino acids: glycine, proline and alanine.

Parallel measurements of muscle and haemolymph during the course of adaptation to hyper- and hypo-osmotic salinities evidence an ecologically-significant rapid response of the isosmotic intracellular regulation, and indicate an exchange of nitrogenous material across the cell membranes.

The results are discussed comparatively and with regard to the theories on the regulation of the nitrogenous contents and osmotic concentrations in the cells.