title: Linking chemical and microbial diversity in marine sponges: possible role for poribacteria as producers of methyl-branched fatty acids.
abstract: Many marine sponges contain massive numbers of largely uncultivated, phylogenetically diverse bacteria that seem to be important contributors to the chemistry of these animals. Insights into the diversity, origin, distribution, and function of their metabolic gene communities are crucial to dissect the chemical ecology and biotechnological potential of sponge symbionts. This study reveals a sharp dichotomy between high and low microbial abundance sponges with respect to polyketide synthase (PKS) gene content, the presence of methyl-branched fatty acids, and the presence of members of the symbiotic candidate phylum "Poribacteria". For the symbiont-rich sponge Cacospongia mycofijiensis, a source of the tubulin-inhibiting fijianolides (=laulimalides), near-exhaustive large-scale sequencing of PKS gene-derived PCR amplicons was conducted. Although these amplicons exhibit high diversity at the sequence level, almost all of them belong to a single, architecturally unique group of PKSs present in "Poribacteria" and are proposed to synthesize methyl-branched fatty acids. Three components of this PKS were studied in vitro, providing initial insight into its biochemistry.
authors.affiliation: Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121 Bonn, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hochmuth
authors.forename: Holger
authors.initials: H
authors.lastname: Niederkrüger
authors.forename: Christine
authors.initials: C
authors.lastname: Gernert
authors.forename: Alexander
authors.initials: A
authors.lastname: Siegl
authors.forename: Stefan
authors.initials: S
authors.lastname: Taudien
authors.forename: Matthias
authors.initials: M
authors.lastname: Platzer
authors.forename: Phillip
authors.initials: P
authors.lastname: Crews
authors.forename: Ute
authors.initials: U
authors.lastname: Hentschel
authors.forename: Jörn
authors.initials: J
authors.lastname: Piel
mesh_terms: D000818:Animals; D001419:Bacteria / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000737:chemistry / Q000378:metabolism*; D005796:Genes; D048630:Polyketide Synthases / Q000235:genetics*; D011161:Porifera / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013559:Symbiosis
chemical_list: D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S; D048630:Polyketide Synthases