Étude séismique par réflexion au sud de l'île du Planier (Marseille) (Résumé and Summ.) : Muraour P. et E. Groubert, 1963. Rapp. Proc. Verb. Réunions, Comm. Int., Exp. Sci., Mer. Méd., Monaco, 17 (3): 987

Abstract

Total phospholipids, choline phosphoglycerides, ethanolamine phosphoglycerides, phosphatidyl-serine + phosphatidylinositol, and sphingomyelin were isolated in winter and summer from whole bodies of the intertidal barnacles, Balanus balanoides (L.) and Elminius modestus Darwin. The fatty acid compositions were determined for these fractions for two years. Parallel determinations of cold tolerance indicated that the tolerance of Balanus balanoides to low temperatures increased from summer to winter while that of Elminius modestus remained unchanged. Fractions from both species showed seasonal changes in fatty acid composition but those which were consistent between years and which differed between species were confined to sphingomyelin. In E. modestus these changes involved a winter to summer increase in monounsaturated fatty acid levels met by a decrease in the level of saturated fatty acids. The trend for Balanusbalanoides was similar but less marked. Sphingomyelin was also characteristic in having a low level of polyunsaturated fatty acids, in contrast with other phospholipid fractions examined. It is suggested that seasonal changes in the fatty acid composition of sphingomyelin, a phospholipid which is located primarily in the plasma membrane, may play some as yet undetermined rôle in the avoidance of freezing injury resulting from damage to this membrane.