title: GC-MS structural characterization of fatty acids from marine aerobic anoxygenic phototrophic bacteria.
abstract: The FA composition of 12 strains of marine aerobic anoxygenic phototrophic bacteria belonging to the genera Erythrobacter, Roseobacter, and Citromicrobium was investigated. GC-MS analyses of different types of derivatives were performed to determine the structures of the main FA present in these organisms. All the analyzed strains contained the relatively rare 11-methyloctadec-12-enoic acid, and three contained 12-methyl-octadec-11-enoic acid, which has apparently never been reported before. High amounts of the very unusual octadeca-5,11-dienoic acid were present in 9 of the 12 strains analyzed. A FA containing a furan ring was detected in three strains. Analytical data indicated that this FA was 10,13-epoxy-11-methyloctadeca-10,12-dienoic acid. A very interesting enzymatic peroxidation of the allylic carbon 10 of cis-vaccenic acid was observed in three strains. Deuterium labeling and GC-MS analyses enabled us to demonstrate that this enzymatic process involves the initial dioxygenase-mediated formation of 10-hydroperoxyoctadec-11(cis)-enoic acid, which is then isomerized to 10-hydroperoxyoctadec-11(trans)-enoic acid and converted to the corresponding hydroxyacids and oxoacids. Different biosynthetic pathways were proposed for these different compounds.
authors.affiliation: Laboratoire de Microbiologie de Géochimie et d'Ecologie Marines (UMR 6117), 13288 Marseille, France. rontani@com.univ-mrs.fr
authors.forename: J F
authors.initials: JF
authors.lastname: Rontani
authors.forename: S
authors.initials: S
authors.lastname: Christodoulou
authors.forename: M
authors.initials: M
authors.lastname: Koblizek
mesh_terms: D001420:Bacteria, Aerobic / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry; D008041:Linoleic Acids; D008386:Marine Biology; D015394:Molecular Structure; D009829:Oleic Acids; D020560:Proteobacteria / Q000737:chemistry*
chemical_list: D005227:Fatty Acids; D008041:Linoleic Acids; D009829:Oleic Acids; C064523:11-methyloctadeca-12-enoic acid; C096139:10,13-epoxy-11-methyloctadeca-10,12-dienoic acid; C050413:11-octadecenoic acid