ACETATE INCORPORATION INTO THE LIPIDS OF THE ANEMONE ANTHOPLEURA-ELEGANTISSIMA AND ITS ASSOCIATED ZOOXANTHELLAE

A. elegantissima containing zooxanthelle and isolated zooxanthellae, incubated with acetate-1-14C under both light and dark conditions readily incorporate radioactivity into their total lipid pools. In both cases, the specific activity was greatly increased in the light. Dark-incubated anemones and isolated zooxanthellae incorporate activity predominantly into polar lipid; the remainder being present principally in the triglyceride moiety. Light-incubated organisms show a dramatic redistribution of isotope towards greatly increased triglyceride and wax ester incorporation, with a concomitant drop in polar lipid. Under light conditions, 70-75% of the radioactivity found in the fatty acids of the total zooxanthellae lipid was present in hexadecanoic (16:0) and octadecenoic (18:1) fatty acids. These are the 2 major fatty acids by mass. Octadecanoic acid (18:0) is less than 5% by mass. Octadecenoic acids may arise by elongation of hexadecenoic acids and that this conversion is blocked in the dark. Fatty acids, primarily in the form of saturated or monoenoic fatty acids, may be translocated from algal to animal cells. No activity was found in either octadecadienoic (18:2) or octadecatrienoic (18:3) acids. The significance of these data is discussed.