FORMATION OF PHOSPHOLIPID NITROGENOUS BASES IN EURYHALINE FISH AND CRUSTACEANS - I - EFFECTS OF SALINITY AND TEMPERATURE ON SYNTHESIS OF PHOSPHATIDYLSERINE AND ITS DECARBOXYLATION

Contribution of base-exchange of serine with other phospholipids for t he synthesis of phosphatidylserine (PS), followed by PS decarboxylatio n to phosphatidylethanolamine (PE) and N-methylation of PE was studied , in vivo and in vitro, in euryhaline fish and crustaceans. Incorporat ion of [H-3]serine and [H-3]ethanolamine into PS, PE and PC was determ ined to assess metabolic dependence of these three phospholipids in di fferent conditions of salinity and temperature. Salinity has the stron ger effect on the PS decarboxylation and later on the methylation of P E species provided by this pathway in tissues of euryhaline fish and c rustacea. The specific changes observed in the metabolism of the molec ular species synthesized through these pathways might be one mechanism allowing the rapid adaptation of euryhaline fish and crustaceans to d ifferent salinity and/or temperature. (C) 1998 Elsevier Science Inc. A ll rights reserved.