AUTHOR=Sandargo Birthe , Jeske Olga , Boedeker Christian , Wiegand Sandra , Wennrich Jan-Peer , Kallscheuer Nicolai , Jogler Mareike , Rohde Manfred , Jogler Christian , Surup Frank 

TITLE=Stieleriacines, N-Acyl Dehydrotyrosines From the Marine Planctomycete Stieleria neptunia sp. nov.

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.01408

DOI=10.3389/fmicb.2020.01408

ISSN=1664-302X

ABSTRACT=<p>Bacteria of the phylum <italic>Planctomycetes</italic> occur ubiquitously in marine environments and play important roles in the marine nitrogen- and carbon cycle, for example as scavengers after phototrophic blooms. Here, we describe the isolation and characterization of the planctomycetal strain Enr13<sup>T</sup> isolated from a <italic>Posidonia</italic> sp. biofilm obtained from seawater sediment close to Panarea Island, Italy. Phylogenetic tree reconstruction based on 16S rRNA gene sequences and multi-locus sequence analysis supports the delineation of strain Enr13<sup>T</sup> from characterized species part of the phylum of <italic>Planctomycetes</italic>. HPLC-MS analysis of culture broth obtained from strain Enr13<sup>T</sup> revealed the presence of lipophilic metabolites, of which the major compound was isolated by preparative reversed-phase HPLC. The structure of this compound, named stieleriacine D (<bold>1</bold>), was elucidated utilizing HRESIMS, 1D- and 2D-NMR data as a new <italic>N</italic>-acylated dehydrotyrosine derivative. Its biosynthesis was proposed based on an <italic>in silico</italic> gene cluster analysis. Through analysis of the MS/MS spectrum of <bold>1</bold> and its minor derivative, stieleriacine E (<bold>2</bold>), it was possible to assign the structure of <bold>2</bold> without isolation. <bold>1</bold> showed antibacterial activity, however, the wide distribution of structurally related compounds indicates a potential role as a signaling molecule.</p>