Cytochemical and physiological studies of the energetic metabolism and osmotrophy in Sagitta friderici (chaetognath)

Abstract

Different glucidic labelled compounds were used for carbohydrate metabolism exploration, tissular glycogen storage localization and amino acid uptake response to osmotic variation in the adult of Sagitta friderici.After [1-14C] glucose or [6-14C] glucose (osmotrophic) assimilation, the relative activity of the different metabolic pathways (glycolysis–citric acid cycle and pentose cycle) have been estimated by means of a micro-radiorespirometric method. The kinetics of expired 14CO2 showed that adult Sagitta mainly used the glycolytic–Krebs cycle rather than the pentose cycle in glucose catabolism.After 2-deoxy-D-[1-14C] glucose (osmotrophic) assimilation, tissular glycogen storages were localized. It was shown that glycogen deposits are abundant in several tissues except the locomotor muscles, which probably represent the main glucose consumers in these very active animals. The problem of glucose transport from the storage localizations to the sites of utilization has been discussed.The L-3H-leucine uptake variations into the Sagitta body after an osmotic shock have been estimated.