title: Odd-chain polyunsaturated fatty acids in thraustochytrids.
abstract: A series of unusual odd-chain fatty acids (OC-FA) were identified in two thraustochytrid strains, TC 01 and TC 04, isolated from waters off the south east coast of Tasmania, Australia. FA compositions were determined by capillary GC and GC-MS, with confirmation of polyunsaturated fatty acids (PUFA) structure performed by analysis of 4,4-dimethyloxazoline derivatives. PUFA constituted 68-74% of the total FA, with the essential PUFA; eicosapentaenoic acid (20:5ω3, EPA), arachidonic acid (20:4ω6, AA) and docosahexaenoic acid (22:6ω3, DHA), accounting for 42-44% of the total FA. High proportions of the saturated OC-FA 15:0 (7.1% in TC 01) and 17:0 (6.2% in TC 04) were detected. The OC-FA 17:1ω8 was present at 2.8% in TC 01. Of particular interest, the C₂₁ PUFA 21:5ω5 and 21:4ω7 were detected at 3.5% and 4.1%, respectively, in TC 04. A proposed biosynthesis pathway for these OC-PUFA is presented. It is possible that the unsaturated OC-PUFA found previously in a number of marine animals were derived from dietary thraustochytrids and they could be useful biomarkers in environmental and food web studies.
authors.affiliation: Energy Transformed National Research Flagship, CSIRO Marine and Atmospheric Research, GPO Box 1538, Hobart TAS 7001, Australia. kim.leechang@csiro.au
authors.forename: Kim Jye Lee
authors.initials: KJ
authors.lastname: Chang
authors.forename: Maged P
authors.initials: MP
authors.lastname: Mansour
authors.forename: Graeme A
authors.initials: GA
authors.lastname: Dunstan
authors.forename: Susan I
authors.initials: SI
authors.lastname: Blackburn
authors.forename: Anthony
authors.initials: A
authors.lastname: Koutoulis
authors.forename: Peter D
authors.initials: PD
authors.lastname: Nichols
mesh_terms: D016718:Arachidonic Acid / Q000737:chemistry; D015118:Eicosapentaenoic Acid / Q000737:chemistry; D005231:Fatty Acids, Unsaturated / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D008401:Gas Chromatography-Mass Spectrometry; D015394:Molecular Structure; D010080:Oxazoles / Q000737:chemistry; D012623:Seawater; D058009:Stramenopiles / Q000737:chemistry*; D013648:Tasmania
chemical_list: D005231:Fatty Acids, Unsaturated; D010080:Oxazoles; D016718:Arachidonic Acid; C057549:4,4-dimethyloxazoline; D015118:Eicosapentaenoic Acid; C026219:docosapentaenoic acid