title: Anaerobic biosynthesis of unsaturated fatty acids in the cyanobacterium, Oscillatoria limnetica.
abstract: The mechanism for synthesis of monounsaturated fatty acids under aerobic and anaerobic conditions was studied in the facultative anaerobic cyanobacterium, Oscillatoria limnetica.  The hexadecenoic acid (C16:1) of aerobically grown O. limnetica was shown to contain both the delta 7 (79%) and delta 9 (21%) isomers, while the octadecenoic (C18:1) acid was entirely the delta 9 acid.  Incorporation of [2-14C] acetate into the fatty acids under aerobic conditions resulted in synthesis of the delta 7 and delta 9 C16:1 and the delta 9 C18:1.  Synthesis of unsaturated fatty acids in the presence of DCMU required sulfide.  Anaerobic incubations in the presence of DCMU and sulfide (less than 0.003% atmospheric oxygen) resulted in a two-fold increase in monounsaturated fatty acids of both delta 7 and delta 9 C16:1 and delta 9 and delta 11 C18:1.  The synthesis of these is characteristic of a bacterial-type, anaerobic pathway.
authors.affiliation: Planetary Biology Branch, NASA, Ames Research Center, Moffett Field, CA 94035, USA.
authors.forename: L L
authors.initials: LL
authors.lastname: Jahnke
authors.forename: B
authors.initials: B
authors.lastname: Lee
authors.forename: M J
authors.initials: MJ
authors.lastname: Sweeney
authors.forename: H P
authors.initials: HP
authors.lastname: Klein
mesh_terms: D000085:Acetates / Q000378:metabolism; D000693:Anaerobiosis; D005075:Biological Evolution; D003470:Culture Media; D000458:Cyanobacteria / Q000187:drug effects / Q000378:metabolism*; D004237:Diuron / Q000494:pharmacology*; D005229:Fatty Acids, Monounsaturated / Q000378:metabolism*; D006540:Herbicides / Q000494:pharmacology*; D007536:Isomerism; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D013440:Sulfides / Q000494:pharmacology*
chemical_list: D000085:Acetates; D003470:Culture Media; D005229:Fatty Acids, Monounsaturated; D006540:Herbicides; D013440:Sulfides; D004237:Diuron; D010100:Oxygen