Ref ID : 3899
Edna S. Kaneshiro, Linda S. Beischel, Steven J. Merkel, and Dennis E. Rhoads; The Fatty Acid Composition of Paramecium aurelia Cells and Cilia: Changes with Culture Age. J.Protozool. 26(1):147-158, 1979
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The fatty acids of whole cells and cilia from Paramecium tetraurelia strains 51s and (d4)95 and from Paramecium octaurelia strain 299s were identified. Ciliates were grown axenically in 3 types of culture media. More than 30 fatty acid species were identified and these structures determined by gas chromatography, mass spectrometry, argentation chromatography, hydrogenation, and fragmentation technics. The major fatty acids were hexadecanoic, octadecanoic, 9-octadecenoic, 9,12-octadecadienoic, 6,9,12-octadecatrienoic, and 5,8,11,14-eicosatetraenoic acids. Minor variations in fatty acid composition were observed in cells grown in the different culture media as well as among the 3 strains. Major changes in fatty acid compositions occurred with culture age and cell density. The cells accumulated exogenous lipids in cytoplasmic vesicles. These lipids were utilized as culture age progressed. Both cellular volume and lipid content were greater in young than in older cultures. Fatty acid compositions of both whole cells and cilia changed with age and had a relative decrease in saturated, short-chained and odd-numbered carbon acids. Cilia lipids were enriched in long-chained, polyunsaturated acids as compared to lipids in whole cell extracts. Eicosatetraenoic acid (arachidonic acid) increased to the greatest extent with age in both cellular and ciliary lipids, accounting for 20-60% of the total fatty acids in cilia. The age-related change in fatty acid composition in Paramecium is among the largest observed in eukaryotic organisms. It was concluded that some minor fatty acids found in Paramecium lipids were incorporated directly from certain culture media and that Paramecium had w3, 6, and 9 pathways for polyunsaturated fatty acid biosynthesis.