ETHER LIPIDS AND PLATELET-ACTIVATING-FACTOR - EVOLUTION AND CELLULAR FUNCTION

This review considers the relation between the evolution of ether lipi ds and platelet-activating factor (PAF) in living organisms for the fi rst time. Ether lipids are shown to be the main structural lipid compo nents in the cells of the most primitive organisms on the Earth; durin g evolution they were gradually substituted for lipids with ester and vinyl bonds. Synthesis of PAF has been found in some bacteria, protozo ans, yeasts, plants, marine invertebrates, lower vertebrates, and mamm als. The regulatory role of PAF is suggested to already appear in prot ozoans and later be maintained during the subsequent evolution of livi ng organisms. During evolution, functions of PAF in the cell have been changing and enlarging, while ether lipids have been gradually losing their role as the main structural lipid component of the cells of liv ing organism.