Synthesis of unsaturated fatty acids in the slime mold Physarum polycephalum and the zooflagellates Leishmania tarentolae, Trypanosoma lewisi, and Crithidia sp.: a comparative study

Abstract

On the basis of the unsaturated fatty acids which they synthesize, protists can be grouped in a meaningful way. Thus, the unsaturated fatty acids of the true slime mold are identical with the unsaturated fatty acids of the soil amoebae Acanthamoeba and Hartmannella but have no resemblance to those of the cellular slime mold Dictyostelium. Among the zooflagellates, Leishmania enriettii and Leishmania tarentolae synthesize unsaturated fatty acids that are very similar to those of the phytoflagellates Euglena, Ochromonas, and Chlamydomonas, while Trypanosoma lewisi and especially Crithidia have a different pattern of unsaturated fatty acids which more closely resembles that of the ciliated protazoa.The unsaturated fatty acids of the true slime mold Physarum polycephalum include oleate, linoleate, 11-eicosenoate, 11,14-eicosadienoate, 8,11,14-eicosatrienoate, and arachidonate. L. tarentolae synthesizes 6,9,12-octadecatrienoate and 9,12,15-octadecatrienoate as well as polyunsaturated 20- and 22-carbon fatty acids derived from both of these 18-carbon acids. T. lewisi synthesizes 6,9,12-octadecatrienoate. Crithidia synthesizes 6,9,12-octadecatrienoate, 8,11,14-eicosatrienoate, and 4,7,10,13,16-docosapentaenoate but not 9,12,15-octadecatrienoate or any acids derived from it. Leishmania and Trypanosoma have been shown to convert stearate directly to oleate.

Keywords

• protozoal fatty acids
• unsaturated fatty acids
• fatty acid biosynthesis
• Crithidia sp
• Leishmania tarentolae
• Physarum polycephalum